TEACHER’S GUIDE for Middle Level Science Classrooms
National Science Teachers Association Dear Science Teacher,
What captures the interest of students? Food! A proven motivator, interest in food can be used to engage students in inquiry-based science. Never before has food science received the public attention it’s receiving now — from scientists and public health officials to lawmakers and the media.
Taking advantage of this broad public interest, coupled with the richness of recent advances in food science, the U.S. Food and Drug Administration (FDA) and the National Science Teachers Association (NSTA) formed a partnership to develop teaching and learning materials. FDA is an agency of the U.S. government authorized by Congress to inspect, test, and set safety standards for all food, except meat, poultry, and processed eggs. NSTA is the world’s largest professional organization dedicated to the teaching of science. Its mission is to promote excellence and innovation in science teaching and learning for all. Leading FDA food scientists from across the country provided their expertise in designing challenging laboratory experiments and activities for this program in collaboration with an expert panel of science teachers coordinated by NSTA.
We are pleased to present you with a copy of Science and Our Food Supply. This innovative, supplemental curriculum introduces students to the fundamentals of microbiology, while at the same time imparting important public health information. Custom designed for use by middle level science teachers, the emphasis is on an inquiry approach, which is in alignment with the National Science Education Standards.
Science and Our Food Supply suggests many useful teaching ideas and strategies. FDA and NSTA have also partnered in the development and offering of a “Professional Development Program in Food Science” designed to better prepare science teachers in the use of the curriculum materials to maximize the learning opportunities for their students. If you are interested in this program or other workshops and support opportunities, please contact the NSTA Professional Programs Division (www.nsta.org).
We are confident that you and your students will find Science and Our Food Supply to be a useful guide to an engaging and relevant learning experience.
National Science Teachers Association www.cfsan.fda.gov www.nsta.org TABLE OF CONTENTS Welcome to Up Front A Message from the Food and Drug Administration and the National Science Teachers Association...... 2 Food Safety Matters! ...... 4 Program at a Glance ...... 5 You and your students are about to experience a Highlights of Your Teacher’s Guide ...... 6 unique program that makes food safety an integral Activities and Experiments User–Friendly Format . . . . . 7 part of your science curriculum. Safety First in the Laboratory ...... 8 Food Safety = Science! Laboratory Procedures...... 9 When it comes to making science relevant for National Science Education Standards Chart . . . . 10-11 your students, what better way than to apply it to something that’s part of their everyday lives? Food Activities and Experiments gives you an ideal springboard for bringing a host Module 1: Understanding Bacteria of science concepts to life in your classroom! Science Content in the Video/DVD ...... 12-14 The Big Picture (activity) ...... 15-17 Science and Our Food Supply includes timely food safety science that you won’t find anywhere Bacteria Everywhere (lab)...... 18-24 else. It takes the methods of real-life scientists The 12 Most Unwanted Bacteria (activity) . . . . . 25-28 who are working every day to keep our food supply safe — and turns their strategies and goals into Module 2: Farm hands-on experiences for your own students. Science Content in the Video/DVD ...... 29-30 Chain of Food (activity) ...... 31-33 You’ll find in-depth activities and experiments covering a broad range of topics, including: Module 3: Processing and Transportation Science Content in the Video/DVD ...... 34-35 • Bacteria, including Foodborne Pathogens Blue’s the Clue (lab)...... 36-41 • Pasteurization Technology Mystery Juice (lab)...... 42-44 • The Science of Cooking a Hamburger Ultra High Pressure Treatment (activity) ...... 45-47 • DNA Fingerprinting • Outbreak Analysis Module 4: Retail and Home Science Content in the Video/DVD ...... 48-49 Supermarket Smarts (activity) ...... 50-53 The Science of Cooking a Hamburger: Cooking Right (lab) ...... 54-59 A Chilling Investigation (lab) ...... 60-62 Crossed Up! (lab) ...... 63-66 Science and Hands off, Bacteria! (activity) ...... 67-70 Our Food Supply is classroom-tested. Module 5: Outbreak and Future Technology It was developed in Science Content in the Video/DVD ...... 71-72 conjunction with an Outbreak Alert — Shigella (activity) ...... 73-77 experienced team of Beef Blasters (activity) ...... 78-81 middle level science teachers. Evaluation Activity Lose a Million Bacteria Game...... 82-85
Resources ...... 86
Visit www.foodsafety.gov/~fsg/teach.html for a multitude of Web resources.
Permission is hereby granted in advance for the reproduction of these print materials in their entirety. FOOD SAFETY MATTERS! . . .
To Everyone In 1999, the Centers for Disease Control and Prevention (CDC) presented the following statistics on reported cases of foodborne illnesses in the United States: • 76 million gastrointestinal illnesses • 325,000 hospitalizations • 5,000 deaths To Students An awareness of food safety risks are especially critical if your students: • prepare their own food at home • prepare food for younger siblings or grandparents Fast-food • prepare food for children in their care restaurants • work in restaurants, supermarkets, and other places that sell, handle, employ more high and serve food school students than any other Learning about food safety will help students better understand industry. decisions and practices that can truly impact their personal health. For Some, the Risks Are Even Greater People in the following at-risk categories are more likely than others to get sick from harmful bacteria that can be found in food. And once they’re sick, they face the risk of serious health problems, even death: • the elderly • young children • pregnant women • people with weakened immune systems
Nearly 25% of the Plus, underlying illnesses, such as diabetes, some cancer treatments, and U.S. population is kidney disease may increase a person’s risk of foodborne illness. at risk for serious symptoms from It’s a Matter of Changing Times foodborne illness. There are many issues that make food safety more of an issue now than ever before. For instance:
• Meals Prepared Away from Home — Today, nearly 50% of the money we spend on food goes toward buying food that others prepare — like “take out” and restaurant meals. Plus, a growing number of Americans eat meals prepared and served in hospitals, nursing homes, and day-care and senior centers.
• Food from Around the Globe — Food in your local grocery store comes from all over the world, which may bring us new microorganisms. This presents a whole new set of modern food safety challenges.
• Resistant Bacteria — In 1950, scientists knew of 5 foodborne pathogens. In 2000, there were at least 25 foodborne pathogens, including 20 newly discovered ones.
The Science and Our Food Supply program is your innovative classroom link between food . . . science . . . and health.
So let’s get started!
4 FOOD SAFETY PROGRAM AT A GLANCE . . . Now you can teach important science concepts using the timely topic of food safety with Science and Our Food Supply. It’s a feast of food safety information and hands-on, minds-on lessons!
Inside you’ll find a wide selection of inquiry-based lessons that provide you with several weeks of instruction. Guided by the National Science Education Standards, this program serves as a supplemental curriculum that can be easily incorporated into your Biology, Life Science, or other science classes. Your students will get the inside scoop on microbes — how they live, grow, and s-p-r-e-a-d. They’ll go behind the scenes and be introduced to the latest food safety technologies that affect the foods they eat, and meet real-life scientists in a wide variety of science disciplines.
MODULAR FORMAT The program is divided into the following 5 modules with activities and experiments related to each module: Module 1 — Understanding Bacteria Module 2 — Farm Module 3 — Processing and Transportation Module 4 — Retail and Home Module 5 — Outbreak and Future Technology COMPONENT CONNECTIONS The following 3 components are designed to provide a variety of learning opportunities.
Science and Our Food Supply Teacher’s Guide • Includes 15 hands-on, minds-on activities and experiments • Features fun, creative ways for presenting the lessons • Introduces fascinating facts about food safety • Guided by the National Science Education Standards
Dr. X and the Quest for Food Safety Video/DVD • Features a savvy food scientist (Dr. X) and student (Tracy) to introduce and reinforce the science concepts in the activities and experiments • Explores behind-the-scenes research in laboratories • Profiles scientists in food safety careers • Provides little-known, pop-up facts
BONUS! Check out the careers section following Module 5. It features more in-depth information about the scientists in the video/DVD.
Food Safety A to Z Reference Guide • Offers the most accurate, up-to-date information on food safety • Features an easy-to-use alphabetical format • Includes more than 100 terms • Presents practical, in-depth information on the 4 Cs of Food Safety (Clean, Cook, Chill, and Combat Cross-Contamination) • Introduces healthy practices for handling, preparing, cooking, and serving a variety of foods • Includes a vivid Farm-to-Table Continuum illustration • Showcases interviews with real-life scientists • Includes tips, fun facts, visuals, and answers to your most frequently asked food safety questions
FOOD SAFETY 5 HIGHLIGHTS OF YOUR TEACHER’S GUIDE
What’s Inside . . .
Safety First offers tips and techniques for staying safe in the lab.
Lab Procedures highlights basic laboratory procedures for conducting the experiments.
National Science Education Standards Chart is an at-a-glance overview of all the activities/experiments and the National Science Education Standards that they cover.
Science Content begins each module with a review of the science content presented in the video/DVD. Fascinating facts are also featured. Read this section before watching the video/ DVD module or conducting the activities and experiments.
Activities and Experiments • Activities explore food science concepts and encourage student creativity. • Experiments are based on scientific inquiry that explores real-life food science while teaching good scientific The National Science Teachers methods and laboratory practices. Association (NSTA) has launched • SciLINKS® links Internet resources with the specific a bold new project that activity or experiment (see sidebar at left). blends resource materials and telecommunications into a dynamic • Student Sheets are reproducible and accompany new educational tool. This effort, several of the activities and experiments. A master lab called sciLINKS®, links specific report sheet that students can use for recording their supplemental resource locations observations, results, and other data is also included. with rich Internet resources. Resources lists videos, reference books, science supplies, NSTA has incorporated sciLINKS and more. In addition to this listing, check out into this supplemental curriculum. www.foodsafety.gov/~fsg/teach.html for a multitude You’ll find an icon in the Resources of Web resources. section of several of the activities and experiments with the sciLINKS Connections to the URL (www.scilinks.org) and a code. Go to the sciLINKS Web site, National Science Education Standards sign in, type the code from the During the production of this curriculum, developers and page you are reading, and you will educator reviewers recognized the need to connect this receive a list of URLs selected by program to the National Science Education Standards science educators. (NSES). The National Standards provide the guidance for Sites are chosen for accurate many state and local science education frameworks for what and age-appropriate content. The science content should be taught at particular levels and what underlying database changes students should be able to do and to understand. constantly, eliminating dead or revised sites or simply replacing You should carefully examine local and state frameworks and them with better selections. The ink curriculum guides to determine the best method of integrating may dry on the page, but the science Science and Our Food Supply into the science program of your it describes will always be fresh! school. The Program and System Standards provided in NSES will be helpful in this determination. Appropriate placement within the scope and sequence context of a school’s curriculum will optimize the interdisciplinary connections and enhance the ability of a student to learn key science concepts.
6 FOOD SAFETY /
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(It’s everyone’s responsibility.) FOOD SAFETY CONNECTION: Relates science to actual food safety applications. need to do before conducting the activity or ADVANCE PREPARATION: ADVANCE PREPARATION: experiment. MATERIALS: perform the activity or experiment. Time to review and summarize. Food Safety Food www.foodsafety.gov/~fsg/teach.html What does DNA tell us? tell DNA does What of the source the to determine fingerprint DNA pathogen’s the use epidemiologists bacteria.) Dr. X talked about Dr. his 4 food safety weapons for fighting harmful bacteria; what are they? (Clean, Cook, Chill, and Combat Cross-Contamination) the What’s significance of O157:H7? (E. coli O157:H7 is one kind of causes foodborne illness. X described “baddest the Dr. of the bad”; what was he referring to? (The 12 Most Unwanted Bacteria that cause foodborne illness) What does DNA have to do with bacteria? (DNA encodes the information that enables bacteria to grow, reproduce, and cause illness.) What does science have to do with food safety? (Food safety has everything to do methods to developing dedicated of scientists kinds all are with There controlling bacteria. safe.) supply food our to keep Continuum? Whose responsibility is it to keep our food supply safe along the Farm-to-Table What effect do each of the 4 Cs have on bacteria? (Cleaning removes bacteria from hands and surfaces. Cooking (heat) kills bacteria by breaking down their cell walls. Chilling slows down the bacteria’s metabolism, thus slowing their growth. Combating Cross-Contamination prevents the spread of bacteria from one thing to another.)
See real-life scientists in action! • • Food Safety A to Z Reference Guide
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Guide on page 54. class/grade/school/ your in people Survey have may them of many how out find to faculty illness. foodborne experienced E Check the Internet to learn more about when when about to learn more Internet the Check Initiative. a National became safety food why and Collect articles on food safety from your local paper and TV news reports, and write a report on local food safety issues. Post articles and reports on the class bulletin board. the out Check R A C • • SUMMARY It’s everyone’s responsibility to control the spread of bacteria — from the farmer, the food processor, the person who transports our food, people who work in supermarkets and restaurants, and consumers when they take the food home. EXTENSIONS • • • INSTANT REPLAY INSTANT
in America. If 76 million people become sick due to foodborne illness, ask the students to calculate the percent of the population affected. Discuss the students’ reactions to • There are approximately 274 million people Links Internet resources with the specific activity or experiment
• Suggests activities
video, Module 1 — Module video, for Food Food for Safety Bacteria Understanding YOUR ORDER? Module 1 There’s a lot There’s Food safety is everyone’s responsibility — everyone involved in growing, processing, transporting, and handling our food along all the points distribution in food our complex includes all of us responsibility This system. as we purchase, prepare, and eat our food. Students need to understand that food safety is a very serious issue that affects the well- being of every individual. Because everyone must eat, we’re all at risk of becoming ill if food becomes contaminated. FOOD SAFETY CONNECTION How many of you have for helping students learn more about the topic. EXTENSIONS: Summarizes
Video the video CAN I TAKE CAN I TAKE TIME TO TUNE IN . . . Control and Prevention Foodborne Illness in the U.S. (1999 estimates) 76 million illnesses 325,000 hospitalizations 5,000 deaths pages 52–53 of the of the 52–53 pages , Note: Tell the students that this is only an assumption, and not an actual survey. This information is simply to help the students relate to the statistics that you are about to give them.) thinks they’ve had foodborne illness. how many students in the entire school might have had foodborne illness. been affected by foodborne illness? Write that Write number on the board. Show or review • Ask students: • Now compute what percentage of the class • Using that percentage, ask them to estimate ( • Present this information on the board: prevalent foodborne illness is and to help students realize the seriousness of this issue and how it relates to them.
FOOD SAFETY PROCEDURE Use the 1. following exercise to emphasize how
of science behind keeping our food safe. of our behind keeping science food safe. this become food unit, you’ll Throughout and and experiments conduct scientists X, begin by Dr. meeting Let’s projects. research his dedicated a who’s food scientist crusading life and to bacteria harmful foodborne fighting a on working student her Tracy, and illness, who video science project, teams up with him on his I mission. to you challenge uncover links science as the you food-safety following watch the video: Introduce the Introduce video by explaining: THE BIG PICTURE
Hot plate and skillet and plate Hot Farm-to-Table Safety Food illustration Food Safety A to Z Reference Guide A to Z Reference Safety Food
Quest X the and Dr. BACTERIA UNDERSTANDING
• • • E L U D O M 16 1 SUMMARY: key science concepts learned in the activity or experiment.
to to THE BIG PICTURE One Time: 45-minute class period . Activity activity orange juice, and a and salad juice, orange or pictures Use Option: models. food ACTIVITY AT A GLANCE ACTIVITY AT This activity introduces students to food safety. It includes information about the number of people affected each the year, 4 Cs of Food Safety, the Farm-to-Table Continuum, who’s responsible for keeping our food safe, and the link between food safety and science. The topic is launched by letting the students relate food safety to the foods they like to eat, such as hamburgers, orange juice, and salad. At the end of the activity, Module 1 of the video is shown to set the stage for “Understanding Bacteria.” of glass A hamburger, INTRODUCTION ADVANCE PREPARATION ADVANCE Set up a hot plate and skillet to cook the hamburger as students enter the room. Have a glass of orange juice and a salad sitting on your desk. GETTING STARTED • MATERIALS MATERIALS As students walk in, be cooking a hamburger to entice their senses. Other options are to post a large picture of the food in a conspicuous place, use food models, or dress up as a waiter/ waitress. can You wear an apron and have a pad and a pen readily available for taking your students’ orders. As the students come in, let them comment on the food. Don’t give them an explanation. Let the atmosphere stimulate their curiosity. Indicates an boldface boldface /DVD
Introduces the Introduces
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Briefly Gives the step-by- the Gives LAB boldface
module that’s relevant relevant that’s module . (Answers to questions are are to questions . (Answers The approximate
/DVD experiment FIRST Lab Experiment Indicates a lab Some organisms could be dangerous pathogens. xx). experiments. SAFETY FIRST: important safety precautions when conducting the lab • safety gloves. Wear • Seal inoculated Petri dishes using Parafilm or masking • tape (see page xx). Remind students never to open a dish with organisms growing in it. • Disinfect all lab surfaces before and after working in the lab (see page periods. TIME: amount of time needed for performing the activity or experiment. Time is designated in 45-minute class • hands thoroughly Wash before and after the lab. PROCEDURE: listed in parentheses.) listed step process for the activity or activity the for process step teacher Suggested experiment. by is indicated dialogue italics The activities and experiments are written in this easy-to-understand format: User-Friendly User-Friendly Format ACTIVITY or AT A GLANCE: summarizes the activity or lab experiment. Watch for the following icons . . . TIME TO TUNE IN: video the activity or experiment. It or the offers activity experiment. look should for students challenges as they watch the video SAFETY italics. INTRODUCTION: Provides fun, innovative suggestions for introducing the activity or lab. Suggested teacher dialogue is indicated by ACTIVITIES ACTIVITIES AND EXPERIMENTS Safety First in the Laboratory Preparing for the Lab Experiment • Wash your hands with hot, soapy water. If soap and water are not available, you can use disposable wipes or a hand gel sanitizer. • Wear disposable safety (protective) gloves. Disinfecting Bleach • Tie back long hair. Solution: 20 ml of • Wear safety goggles or regular glasses for microbiology work. liquid household • If possible, wear a lab coat or apron. bleach (chlorine bleach) in 1 L of • NEVER EAT, DRINK, OR CHEW GUM IN THE LAB. Keep your hands, pencils, etc. tap water. out of your mouth. • Disinfect all surfaces with a disinfecting bleach solution before beginning an experiment (see box at right). INAPPROPRIATE BEHAVIOR WILL NOT BE TOLERATED AT ANY TIME IN THE LAB! Safety Gloves Proper Clean-Up • Wear safety gloves when inoculating Petri dishes and • Wear safety gloves and take appropriate defensive when working with raw meat. measures when cleaning up cultures and used Safety gloves are made using many types of equipment. materials, including vinyl, and polyethylene. • Wash all glassware and other instruments in hot, They can be purchased at a local pharmacy, soapy water. Then sterilize (see page 9). supermarket, or through science supply catalogues. • Properly dispose of used Petri dishes and other • When removing safety gloves, be careful not to used equipment. contaminate your hands, items, or surfaces with any • Thoroughly disinfect all surfaces, especially those residue that may be on the gloves. that come in contact with raw meat. • Throw away used gloves immediately after removing • Before leaving the lab, wash your hands with hot, them. Wrap one glove inside the other, then throw soapy water or use a hand gel sanitizer. both gloves away. • Wash your hands with hot, soapy water after removing Disposal of Used Materials and Equipment the gloves. • Check your school, local, or state safety regulations for specific information on how to properly dispose Hot Surfaces of potentially hazardous materials. If there are no • Use thermal gloves or hot-pad holders when working guidelines, follow these precautions: with hot plates, burners, autoclaves, or any other heat source. For Raw Meat Petri Dishes • Unless contaminated with a virulent pathogen in the lab, raw meat and other foods can usually be • Always tape Petri dishes closed after inoculating them. disposed in the regular solid waste. Place the meat • Never open a Petri dish with organisms growing in it. in a sturdy plastic bag, seal, and dispose. It could contain dangerous pathogens! For Used Swabs, Petri Dishes, Pipettes, and Other Pipettes Disposable Equipment • Never pipette by mouth. Always use a pipette bulb or • Use a sturdy plastic bag that won’t leak. pipette aid. • Place the bag in a metal container, such as an • Be careful when attaching a pipette bulb. Hold your empty coffee can. Use one bag/container for each hand close to the end of the pipette where the bulb will team of students conducting the experiments. be attached. Push the bulb on carefully and gently. If • Place used swabs, disposable Petri dishes, pipettes, you push too hard, the pipette could break and you etc. in the bag. could cut yourself. • At the end of the lab, add a disinfecting bleach solution and tightly close the bag. Food in the Lab • Dispose the closed bag in the trash. • NEVER EAT OR DRINK ANY FOOD OR LIQUID USED IN AN EXPERIMENT. Note: Equipment that will be reused should be before after • Thoroughly wash hands and handling and cleaned using hot water and soap and then placed cooking raw meat. in boiling water for 10 minutes or sterilized in an • Wear safety gloves, safety goggles, and lab aprons autoclave. when handling and cooking raw meat.
8 FOOD SAFETY LABORATORY PROCEDURES
Washing Hands Disinfecting Sterilizing Equipment (test tubes, pipettes, etc.)
• Use hot water. Disinfecting Bleach Solution: 20 ml of Options: liquid household bleach (chlorine bleach) • Wet hands and add soap. • Use an autoclave. in 1 L of tap water. • Scrub hands for 20 seconds away • Use dry heat — 160° F to from the running water. Thoroughly To Disinfect Countertops: 180° F (71° C to 82° C) for scrub wrists, under fingernails, • Put solution in spray bottle and label the 3 to 4 hours. around nail beds, and between bottle, “Disinfecting Solution.” • Use chemical agents, such fingers. • Wipe off counters to remove any visible as 5% bleach, ethyl or • Rinse hands under running water. soil. isopropyl alcohol, commercial disinfectants, or iodine • Dry hands thoroughly with clean • Spray the disinfecting solution on solutions. paper towels. counters and leave it on for 2 minutes. Note: If necessary, alcohol disposable Note: Use the solution within 24 hours wipes or hand gel sanitizers can be then dispose it down the drain. Solution substituted for soap and water. will lose its effectiveness in 24 hours.
Inoculating a Petri Dish
1. Label 3. Tape • Divide the Petri dish into sections • Place the cover on the Petri dish and seal it closed using (if applicable), and label the Parafilm or masking tape. bottom (agar side) of the dish using a permanent marker. For Parafilm • Cut a narrow strip • Label along the outer edges and stretch it around of the dish or the sections, so the outside edge of the the labels don’t interfere with covered dish. viewing the organisms.
2. Inoculate For Masking Tape • Use a sterile cotton swab* to wipe the surface or • Cut 2 small pieces of tape liquid being tested. Hold the cotton swab at one and attach them across tape end — do not touch the end that will be used to opposite sides of the dish. inoculate the agar. * If you use a control plate, new, untouched cotton Note: Position the tape so you will be able to see the swabs are good to use. Inoculate the control organisms without removing the tape. plate with a new swab to check for any microbial contamination. 4. Incubate • Place dishes upside down (label side up) in an incubator For a Dry Surface set at 35° C (95° F). • Wet the swab by dipping it in boiled or sterile water. Then, wring out the swab by wiping it against the inside of the container. (If the swab is too wet, the liquid will flow into other sections and the microbial colonies will run into each other.) • Swab the dry surface. Helpful Tips for Viewing Inoculated Petri Dishes
For a Liquid • Use a light box (ask a parent or shop class to make a • Dip the sterile cotton swab light box for your class from plywood and Plexiglas; or, in the liquid. Then, wring borrow a light box from the photography class). Line up out the swab by wiping it all the Petri dishes and compare the results. against the inside of the or container. • Use an overhead projector. Line up the Petri dishes on • Inoculate the nutrient agar the projector and project onto a screen, so the entire using a back-and-forth motion, class can view the results. This is very effective! covering the entire area of the • If neither a light box nor overhead projector is available, plate or section. Do not swab too close to the simply view the plates on a light-colored surface. dividing lines for the next section.
FOOD SAFETY 9 NATIONAL SCIENCE EDUCATION STANDARDS
KEY CODE Module 1 Module 2 3 = Covers the Standard in Depth 2 = Covers the Standard Understanding Bacteria Farm 1 = Touches on the Standard The Big Picture Bacteria 12 Most Unwanted Chain CONTENT STANDARDS Everywhere Bacteria of Food Unifying Concepts and Processes Systems, order, and organization 2 3 3 2 3 3 3 3 2 3 2 Evidence, models, and explanation 2 3 3 3 3 3 3 3 3 3 3 2 3 3 2 Change, constancy, and measurement 2 3 3 3 3 3 3 3 2 2 2 2 3 3 Evolution and equilibrium 1 1 Form and function 2 3 3 3 2 2 2 3 2 3 3 Science as Inquiry Abilities necessary to do scientific inquiry 1 2 1 3 3 3 3 3 3 3 3 3 3 2 2 Understandings about scientific inquiry 1 2 1 3 3 3 3 3 3 3 3 3 3 2 2 Physical Science Properties and changes of properties in matter 2 1 3 1 1 3 Motions and forces 3 3 Transfer of energy 3 3 Life Science Structure and function in living systems 2 Reproduction and heredity 1 3 Regulation and behavior 2 2 Populations and ecosystems 1 Diversity and adaptations of organisms 1 1 3 3 Science and Technology Abilities of technological design 2 2 1 3 3 2 3 3 3 3 3 2 3 3 Understandings about science and technology 2 2 1 3 3 3 3 3 3 3 3 2 3 3 Science in Personal and Social Perspectives Personal health 3 3 3 3 3 3 3 3 3 3 3 3 3 3 2 Populations, resources, and environments 1 1 2 3 1 3 1 3 2 2 Natural hazards 3 3 3 2 3 3 3 3 3 3 1 3 3 Risks and benefits 3 3 3 3 3 3 3 3 3 3 3 3 3 3 2 Science and technology in society 3 3 3 3 3 3 3 3 3 3 3 2 3 3 History and Nature of Science Science as a human endeavor 3 3 3 3 3 3 3 3 3 3 3 2 3 3 Nature of science 3 3 3 3 3 3 3 3 3 3 3 2 3 3 History of science 2 1 2 3 1
10 FOOD SAFETY This chart highlights the way Science and Our Food Supply may be used to address the Science Content Standards found in the National Science Education Standards (NSES). It’s designed as a chart instead of a checklist, since the degree to which a standard may be addressed by the activities is variable. Note the relative rankings suggested by the educators who tested these activities. It became clear through the classroom testing and review process that this curriculum provided some especially good connections to several National Standards that are often missing in other science education resources. In particular, there seemed to be good alignment between the goals and activities of this curriculum and the standards related to Personal Health and Social Perspectives.
Module 4 — Retail and Home Module 5 Module 3 Evaluation Processing and Transportation The Science of Outbreak and Cooking a Hamburger: Future Technology Activity
Lose a Million Blue’s Mystery Ultra High Supermarket Cooking A Chilling Crossed Hands Off, Outbreak Beef Bacteria the Clue Juice Pressure Treatment Smarts Right Investigation Up! Bacteria! Alert Blasters The Game
2 3 3 2 3 3 3 3 2 3 2 2 3 3 3 3 3 3 3 3 3 3 2 3 3 2 2 3 3 3 3 3 3 3 2 2 2 2 3 3 1 1 2 3 3 3 2 2 2 3 2 3 3
1 2 1 3 3 3 3 3 3 3 3 3 3 2 2 1 2 1 3 3 3 3 3 3 3 3 3 3 2 2
2 1 3 1 1 3 3 3 3 3
2 1 3 2 2 1 1 1 3 3
2 2 1 3 3 2 3 3 3 3 3 2 3 3 2 2 1 3 3 3 3 3 3 3 3 2 3 3
3 3 3 3 3 3 3 3 3 3 3 3 3 3 2 1 1 2 3 1 3 1 3 2 2 3 3 3 2 3 3 3 3 3 3 1 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 2 3 3 3 3 3 3 3 3 3 3 3 2 3 3
3 3 3 3 3 3 3 3 3 3 3 2 3 3 3 3 3 3 3 3 3 3 3 3 3 2 3 3 2 1 2 3 1
National Science Education Standards, National Academy Press, Washington, DC, 1996
FOOD SAFETY 11 1 UNDERSTANDING BACTERIA ABOUT THE MODULE Module 1 — Understanding Bacteria — introduces students to the
exciting world of bacteria and food safety. The Big Picture — explains that food safety is everyone’s responsibility. Bacteria Everywhere — shows that bacteria are everywhere and can spread from one surface to the next, potentially contaminating things that come into contact with food.
M O D U L E The 12 Most Unwanted Bacteria — introduces a research project for the most common bacteria that cause foodborne illness.
SCIENCE CONTENT
This section explains the specific science concepts presented in Module 1 of the video/DVD, including fascinating facts relative to the module. Read this section before watching the video module or conducting the activities and experiments.
Food Safety and the Battle with Bacteria The United States has one of the safest food supplies in world, but there’s always room for improvement. The battle to prevent foodborne illness is waged every day because bacteria are everywhere. Food safety has to do with controlling bacteria. And since everyone eats, we all share the responsibility for keeping our food free from harmful bacteria.
Electron Microscope Lan Hu, Ph.D., Dennis J. Kopecko, Ph.D., and Ben Tall, Ph.D. Magnified image of An electron microscope uses electrons instead of visible light Campylobacter jejuni to produce magnified images. It can magnify bacteria a million times their normal size.
Where Bacteria Come from and How They Grow Bacteria are found everywhere, and under the right conditions, they can multiply fast! Each bacterium contains all the genetic information needed to make copies of itself. Bacteria multiply through binary fission, a process in which the cell’s DNA doubles, the cell splits, and two independent cells are formed. Under the right conditions, a single bacterium will double with each division — 2 become 4, 4 become 8, etc. A single cell can turn into millions of cells in a few hours and billions of cells James A. Sullivan/ Cells Alive Bacteria multiplying within one day! This rapid growth is not usually a problem with good bacteria; however, when it occurs with bad bacteria (a.k.a. pathogens), it is “bad” news. As pathogens multiply, some give off harmful toxins or become infectious. If pathogens get into our food and multiply, people can get sick.
FASCINATING S T C A F
1 million bacteria can fit inside 1 square inch.
12 FOOD SAFETY SCIENCE CONTENT 1 E L U D BACTERIA UNDERSTANDING O M
The 12 Most UnWanted Bacteria Campylobacter jejuni Clostridium botulinum Clostridium perfringens Escherichia coli 0157:H7 Listeria monocytogenes
Dr. X, a crusading food Salmonella Enteritidis scientist, listing the 12 Most Salmonella Typhimurium Unwanted Bacteria. Shigella Staphylococcus aureus Vibrio cholerae Vibrio vulnificus Yersinia enterocolitica
Required Conditions for Bacterial Growth
Time/Temperature — Under the right conditions, some bacteria can double their numbers within minutes and form toxins that cause illness within hours. To minimize bacterial growth in foods, it’s important to keep food temperatures below 40° F (4° C) or above 140° F (60° C). The level in between this temperature range is known as the Danger Zone. Nutrients — Bacteria need many of the same nutrients as humans in order to thrive (glucose, amino acids, and some vitamins and minerals). For example, bacteria grow rapidly in high-protein foods like meat, poultry, eggs, dairy, and seafood. Danger Zone pH — Microorganisms thrive in a pH range above 4.6. That’s why acidic foods like vinegar and citrus juices are not favorable foods for pathogenic bacteria to grow; however, they may survive. Moisture — Most bacteria thrive in moist environments; they don’t grow on dry foods. That’s why dry foods like cereals can safely sit out at room temperature. Note: If dry foods like dry cereals or spices become contaminated from infected hands or equipment, bacteria can survive on the food and make people sick, but they can’t grow or multiply until the food is consumed. pH level
FASCINATING S T C A F • Bacteria can multiply quickly — in fact, one cell can double within 20 to 30 minutes. • It takes less than 10 E. coli bacteria to make you sick.
FOOD SAFETY 13 1 SCIENCE CONTENT
How the 4 Cs of Food Safety Control Bacteria If bacteria can grow so rapidly under the right conditions, then how do we control them? It’s simple: Cooking — kills bacteria by breaking down their cell walls and destroying enzymes, which they need to survive. Chilling — slows down the bacteria’s metabolism, thus M O D U L E slowing their growth. Not only can bacteria grow to large UNDERSTANDING BACTERIA The 4 Cs of Food Safety numbers and make people sick, but they can also spread everywhere. That’s where cleaning and combating cross- contamination come in. Cleaning — removes bacteria from hands and surfaces. Combating Cross-Contamination (separating foods) — prevents bacteria from spreading from one item to another.
Emerging Pathogens
Not only can bacteria multiply fast, but they can also mutate (adapt and evolve), a process that results in changes to their genetic code. These changes happen very slowly and can make the bacteria better able to survive. They can change harmless bacteria into harmful bacteria, which often possess a new genetic characteristic like antibiotic resistance.
Howard Hughes Medical Institute How Scientists Can Tell Good Bacteria from Harmful Bacteria Bacteria mutating DNA (deoxyribonucleic acid) is the “genetic blueprint” for all living things. A DNA molecule looks like a double helix that’s shaped like a long ladder twisted into a spiral. The ends are joined to form a continuous loop, like a rubber band. DNA contains the information that gives living things their traits or characteristics. In people, it determines things like physical features, behaviors, and even whether we’re right or left-handed. In bacteria, the DNA molecule encodes the information that enables bacteria to grow, reproduce, and cause illness.
James A. Sullivan/ Cells Alive Scientists use DNA “fingerprinting,” to identify similar groups DNA molecules of bacteria. DNA is treated so that it exhibits its own special pattern. When there is an outbreak of foodborne illness, epidemiologists (scientists who track down the causes of diseases and find ways to control them) try to determine the source of bacteria in foods by examining the pathogen’s DNA “fingerprint.” Then they see if it matches up to “fingerprints” (patterns) from other samples.
14 FOOD SAFETY 1
THE BIG PICTURE E L U D UNDERSTANDINGBACTERIA O M Time: One 45-minute class period
ACTIVITY AT A GLANCE FOOD SAFETY CONNECTION This activity introduces students to food safety. It Food safety is everyone’s responsibility includes information about the number of people — everyone involved in growing, processing, affected each year, the 4 Cs of Food Safety, the transporting, and handling our food along all Farm-to-Table Continuum, who’s responsible for the points in our complex food distribution keeping our food safe, and the link between food system. This responsibility includes all of us safety and science. The topic is launched by letting as we purchase, prepare, and eat our food. the students relate food safety to the foods they like Students need to understand that food safety to eat, such as hamburgers, orange juice, and salad. is a very serious issue that affects the well- At the end of the activity, Module 1 of the video is being of every individual. Because everyone shown to set the stage for “Understanding Bacteria.” must eat, we’re all at risk of becoming ill if food becomes contaminated. GETTING STARTED
MATERIALS • A hamburger, glass of • Hot plate and skillet • Dr. X and the Quest for Food orange juice, and a salad • Food Safety Farm-to-Table Safety video/DVD, Module 1 Option: Use pictures or illustration, pages 52–53 of the — Understanding Bacteria food models. Food Safety A to Z Reference Guide ADVANCE PREPARATION Set up a hot plate and skillet to cook the hamburger as students enter the room. Have a glass of orange juice and a salad sitting on your desk.
INTRODUCTION
As students walk in, be CAN I TAKE YOUR ORDER? cooking a hamburger to Walk up to one student and ask: Can I take your order, please? entice their senses. Other How do you like your hamburger? What would you like on options are to post a large your salad? picture of the food in a conspicuous place, use food Take 2 or 3 more orders and write them down. Then ask students models, or dress up as a (if they haven’t already asked you): What do you think the waiter/waitress. You can hamburger, orange juice, and salad have to do with science? wear an apron and have List their answers on the board, then ask: Which of the foods a pad and a pen readily would you most like to eat? What do you want on it? Is there available for taking your anything that might be on the hamburger, in the orange juice, students’ orders. As the or in the salad that you didn’t order? students come in, let them comment on the food. Don’t You may have to give them a few hints. Hopefully, someone will Aha! You have your first clue to the give them an explanation. mention bacteria. Then say: connection between these foods and science! Let the atmosphere stimulate their curiosity. Now ask: Have you or has anyone you know ever become ill from eating food? Encourage students to express, when? what? and where? How could you get sick from a hamburger, orange juice, or a salad? (You can get sick if harmful bacteria are present in the food.)
FOOD SAFETY 15 1 THE BIG PICTURE
PROCEDURE 1. Use the following exercise to emphasize how • There are approximately 274 million people prevalent foodborne illness is and to help in America. If 76 million people become sick students realize the seriousness of this issue due to foodborne illness, ask the students to and how it relates to them. calculate the percent of the population • Ask students: How many of you have affected. Discuss the students’ reactions to been affected by foodborne illness? this percentage and have them relate it to Write that number on the board. the percentage calculated for the class. Then reiterate the importance of studying food • Now compute what percentage of the class safety. M OUNDERSTANDING BACTERIA D U Lthinks E they’ve had foodborne illness. 2. Let the students form the following 3 teams — hamburger, orange juice, and salad. Then ask: • Using that percentage, ask them to estimate How do you think the hamburger, orange how many students in the entire school juice, or salad got to you? Let them might have had foodborne illness. brainstorm for about 10 minutes and list their (Note: Tell the students that this is only an ideas. This provides the segue to the Farm-to- assumption, and not an actual survey. This Table Continuum. information is simply to help the students 3. Show students the Food Safety Farm-to-Table relate to the statistics that you are about to illustration. Let them cross-check their lists give them.) with the Farm-to-Table Continuum. They may • Present this information on the board: include even more steps, and that’s good! 4. Now ask: Whose responsibility is it to keep this hamburger, orange juice, and Foodborne Illness in the U.S. (1999 estimates) salad safe from harmful bacteria? 76 million illnesses Hopefully, the students will come up with 325,000 hospitalizations it’s everyone’s responsibility, including their own once the food is in their possession. 5,000 deaths Discuss the reasons we all play a role in protecting our food supply. Centers for Disease Control and Prevention
TIME TO TUNE IN . . . Module 1 — Understanding Bacteria
Introduce the video by explaining: There’s a lot • What 4 weapons does Dr. X use to fight of science behind keeping our food safe. harmful bacteria? Throughout this unit, you’ll become food • What is the significance of the mysterious scientists and conduct experiments and O157:H7? research projects. Let’s begin by meeting • What is Dr. X referring to when he talks Dr. X, a crusading food scientist who’s about the “baddest of the bad”? dedicated his life to fighting harmful bacteria and foodborne illness, and Tracy, • What does DNA have to do with bacteria? a student working on her science video What does it tell us? project, who teams up with him on his Tell the students: You’ll be conducting mission. I challenge you to uncover the experiments and doing further research on following food-safety science links as you many of the things you’ll see in the video, watch the video: so pay close attention! Show video/DVD Module 1 — Understanding Bacteria (Time: 15 minutes).
16 FOOD SAFETY THE BIG PICTURE 1 E L U D BACTERIA UNDERSTANDING O M INSTANT REPLAY Time to review and summarize.
1. Dr. X talked about his 4 food safety weapons for fighting harmful bacteria; what are they? (Clean, Cook, Chill, and Combat Cross-Contamination) 2. What’s the significance of O157:H7? (E. coli O157:H7 is one kind of E. coli that causes foodborne illness. E. coli O157:H7 evolved from the harmless E. coli bacterium.) 3. Dr. X described the “baddest of the bad”; what was he referring to? (The 12 Most Unwanted Bacteria that cause foodborne illness) 4. What does DNA have to do with bacteria? (DNA encodes the information that enables bacteria to grow, reproduce, and cause illness.) 5. What does DNA tell us? (When there is an outbreak of foodborne illness, epidemiologists use the pathogen’s DNA fingerprint to determine the source of the bacteria.)
1. What does science have to do with food safety? (Food safety has everything to do with controlling bacteria. There are all kinds of scientists dedicated to developing methods to keep our food supply safe.) 2. Whose responsibility is it to keep our food supply safe along the Farm-to- Table Continuum? (It’s everyone’s responsibility.) 3. What effect do each of the 4 Cs have on bacteria? (Cleaning removes bacteria from hands and surfaces. Cooking (heat) kills bacteria by breaking down their cell walls. Chilling slows down the bacteria’s metabolism, thus slowing their growth. Combating Cross-Contamination prevents the spread of bacteria from one thing to another.)
SUMMARY RESOURCES It’s everyone’s responsibility to control the spread • Food Safety A to Z Reference Guide of bacteria — from the farmer, the food processor, (See the following terms — Bacteria, the person who transports our food, people who Centers for Disease Control and Prevention, work in supermarkets and restaurants, and Deoxyribonucleic Acid, Escherichia coli O157: consumers when they take the food home. H7, Farm-to-Table Continuum, Foodborne Illness, Four Steps to Food Safety, Pathogen, EXTENSIONS pH.) Also see the 4 Cs section beginning on page 54. • Check the Internet to learn more about when and why food safety became a National Initiative. • Dr. X and the Quest for Food Safety video/ DVD Module 1 — Understanding Bacteria • Collect articles on food safety from your local . • Web sites . . paper and TV news reports, and write a report XT on local food safety issues. Post articles and Cells Alive E N Bacteria are reports on the class bulletin board. www.cellsalive.net P everywhere — even in • Check out the Food Safety A to Z Reference Gateway to Government U this classroom! In the Guide, particularly the 4 Cs section beginning Food Safety Information next activity, you’ll on page 54. www.foodsafety.gov join Dr. X’s crusade • Survey people in your class/grade/school/ Introduction to Bacteria by finding where these faculty to find out how many of them may have www.ucmp.berkeley.edu/ organisms live experienced foodborne illness. bacteria/bacteria.html and thrive.
CONNECTION Keyword: Food Safety ER Go to: www.scilinks.org E R See real-life scientists in action! Code: FS300 A
C • www.foodsafety.gov/~fsg/teach.html • Food Safety A to Z Reference Guide
FOOD SAFETY 17 1
BACTERIA EVERYWHERE Time: Two 45-minute class periods
LAB AT A GLANCE FOOD SAFETY CONNECTION Students will be challenged to hypothesize about where most bacteria are found. They will develop an awareness that bacteria Bacteria can spread from hands to food, are everywhere and that various surfaces might have different from food to food, and from surfaces levels of organisms. Students will learn how to work safely with to food. Cross-contamination can be M O D U L E bacteria. In the extension activity, they’ll hypothesize about how controlled by thoroughly washing hands UNDERSTANDING BACTERIA to control the spread of bacteria. The skills learned in this lab and surfaces. will prepare the students for other experiments and activities in the food-safety curriculum. GETTING STARTED MATERIALS ADVANCE PREPARATION For the Class • Prepare or order 3 sterile Petri dishes • Dissecting microscope or hand lens to view microbial containing nutrient agar for each team colonies of 3 to 4 students. You may want to order extra plates for students who • Additional sterile Petri dishes with nutrient agar and want to test additional areas. Note: covers for expanded tests Petrifilm™ plates can be used instead • Disinfecting solution to disinfect lab surfaces (20 ml of of Petri dishes. See Resources on page liquid household bleach in 1 L of tap water, see page 9) 86. • Sterilize (boil) 2 cups of tap water for For Each Team of 3 to 4 Students each team. You can boil the water • 3 sterile Petri dishes with nutrient agar and covers in beakers and then cover with • 2 cups of sterile water aluminum foil until ready to use. • Sterile cotton swabs Students will use the water to wet • Parafilm or masking tape to seal the dishes swabs for testing dry surfaces. Lab Report Outline • Permanent marker • Photocopy the for each student. • Safety gloves • Photocopy the Bacteria Everywhere • Lab Report Outline for each student (page 23) Data Table for each team. • Bacteria Everywhere Data Table to record results (page 24) INTRODUCTION As students walk into the classroom, be peering Make a list of the responses. through a large magnifying glass in search of Some probable answers: bacteria in various sections of the classroom. • Soda machines, door knobs, desks, trash cans, Your students will wonder what you’re doing. door handles, water fountains, faucet handles, Explain to them: Like Dr. X, I’m on a mission bathroom stall doors, toilet seats, biofilm in — to find out where bacteria live and how sink drains, handle on paper-towel dispenser, they thrive. Now tell them: You’re going on lab tables and counters. Allow the students a microorganism safari, and during this to mention things at home, but tell them: For safari you’re going to become “science today, let’s investigate bacteria here at sleuths.” Your assignment is to find areas school. where bacteria are living and come up with a plan to determine which areas have the • If they haven’t mentioned their hands, under most and least bacteria. fingernails, etc., ask: What about you? Could bacteria be on you? Now ask: What do Get the students started by asking: bacteria look like? (Let them discuss this.) • Are there bacteria in this classroom? Can you see them? If you can’t see them, Where? how can you tell that bacteria really exist? • Where else might they be living around This leads us into today’s lab. We’re going the school? to design experiments that allow us to 18 FOOD SAFETY “see” bacteria. BACTERIA EVERYWHERE 1 PROCEDURE E L U D BACTERIA UNDERSTANDING O M
LAB 1 Find The Bacteria
1. Have students work in teams of 3 or 4. Ask 6. Review the important rules of lab safety, each team to select a name and choose at least especially the handling of bacteria in Petri 4 or 6 areas to examine. Have the students dishes (see page 8). try for as many different areas as possible, 7. Give each team 3 Petri dishes. Ask them: Is but make sure the important areas, such as there anything you should do with these hands and/or under the fingernails, are tested dishes before you start your experiment? by at least 2 teams. (If students are searching for bacteria on their hands or under their • Label the dishes on the bottom (agar side). fingernails, they should wash their hands after • Divide the control dish into thirds. Label the they swab those areas.) control plate: agar, wet swab, and dry swab. 2. Now, have each team hypothesize about which Then swab the control plate. areas will have the most bacteria. Which will • Divide and label the other 2 dishes with the have the least bacteria? Why? How fast areas they want to test. will the bacteria grow? Why? • Label the dishes with the date, their team 3. Have them design an experiment to test their name, class, and hour to avoid mix-ups. Label hypothesis. along the side, so you can see the bacterial growth in the center. 4. Let each team present their hypothesis and experimental design to the class. Encourage • For easy and fun identification, students students to discuss the merits of each suggested can swab the plates using their initials. test. This is also an important time for “guided 8. Give the students 10 to 15 minutes to gather inquiry.” For example, you can guide them by their samples and inoculate their dishes. asking a question such as: How can you be • Tape Petri dishes closed. sure that your agar isn’t contaminated? • Place dishes in an incubator at 35° C (95° F) (You should always have a control plate). After or let the dishes sit at room temperature for the group discussions, give teams time to revise the appropriate amount of time. their hypotheses and experimental designs. • Ask students to set up time parameters — 5. Show students how to swab a surface (on dry the number of hours or days they think it will surfaces use a moist swab) and inoculate a Petri take for the bacteria to grow. dish (see page 9). These procedures will be used throughout the unit.
SAFETY FIRST • Wash hands thoroughly before and after the lab. • Disinfect all lab surfaces before and after working in the lab (see page 9). • Wear safety gloves. • Seal inoculated Petri dishes using Parafilm or masking tape (see page 9). • Remind students never to open a dish with organisms growing in it. Some organisms could be dangerous pathogens. • After the experiment is completed, discard all disposable dishes using safe techniques (see page 9).
FOOD SAFETY 19 1 BACTERIA EVERYWHERE
LAB 2 Observe Bacteria and Record Results
1. Have students observe the bacterial growth 4. Ask students: Were there any differences in and record the results. Students can use the your results compared to the other teams? Bacteria Everywhere Data Table to record their How did your results support or reject results. Tip: Ask the students to draw their your hypothesis? Petri dishes on the back of the Data Table and
M O D U L E 5. Are the organisms good or harmful illustrate the organisms that are growing.
UNDERSTANDING BACTERIA UNDERSTANDING organisms? (With this experiment, students 2. Students can analyze the results based on their will not be able to identify good versus harmful observations. Ask them: organisms — they would need specific agars • What do you see? (Their first observation to grow and identify specific organisms. The may be the number of bacterial colonies. If purpose of the experiment is to demonstrate that so, use a 0–5 scale for rating the quantity. bacteria are everywhere and different surfaces Guide students in ranking the results.) have different levels of organisms. Also, stress that not all bacteria are harmful. In fact, most • What else do you notice about the bacteria are beneficial to us.) colonies? (Their next observation may be the 6. Be sure to properly dispose of the Petri dishes size and shape of the organisms.) (see page 8). • Why do they look different? (Different 7. Ask students to write a lab report (see the Lab microorganisms have different characteristics.) Report Outline). 3. Have each team report the following to the class: the areas they sampled, the number of organisms they observed, and the characteristics (size, shape, and color) of the This lesson involves the following 3 steps in organisms. gathering information: 1. Isolate the sample. 2. View the sealed plates under a dissecting microscope or a hand magnifier. 3. Consider the number of organisms and the diversity of the colonies.
20 FOOD SAFETY BACTERIA EVERYWHERE 1 E L U D UNDERSTANDINGBACTERIA O M INSTANT REPLAY Time to review and summarize.
(shown in The Big Picture activity) 1. How do bacteria multiply? (Bacteria multiply through a process called binary fission — where the cell’s DNA doubles. The cell splits and two independent cells are formed.) 2. How fast can bacteria multiply? (Bacteria can multiply really fast — from a single cell to millions in 10 to 12 hours!) 3. What’s the difference between an electron microscope and a light microscope? (Electron microscopes magnify way beyond what our light microscopes do. They magnify images up to a million times their actual size, and they use electrons instead of visible light to get magnified images.) 4. In the video, why was Dr. X so concerned about what happened at the Barkley house? (The cutting board that Mr. Barkley used to prepare the raw poultry was not properly cleaned before Alex used it to cut up raw vegetables for the salad. Dr. X was concerned that the raw juices from the poultry could have contaminated the raw vegetables.)
Lab Procedure:
1. How do you know the agar and swabs used to collect samples were free from microorganisms? (Make a control plate.) If the agar or swabs were not free from microorganisms, explain how this would affect your results. (Results could be misleading because of contamination.) 2. What do the data you've collected have to do with the food you eat? (Bacteria are everywhere and can be transferred from surfaces to food and from hands to food.) 3. Why do certain surfaces have more bacterial growth than others? (Bacteria thrive in certain environments depending on the moisture level, temperature, time, pH, etc.) 4. How would you know if the organisms you observed were harmful or not? (You would need specific agars to grow and identify specific organisms, so in this experiment you wouldn’t know.) 5. Are all bacteria bad? (No, most bacteria are beneficial to us.)
Application to Food Safety:
1. How can bacteria transfer from objects to foods, from people to foods, and from foods to other foods? (By contact with contaminated objects, hands, and food) 2. Which of the 4 Cs applies to the data you've collected? (Clean and Cross- Contamination) 3. Why is it important to thoroughly clean some surfaces more than others? (Bacteria thrive in some areas more than others because some areas may have more opportunities for contamination and for growth.) 4. What are your suggestions for cleaning surfaces during food preparation? (Allow student suggestions.) 5. Based on your findings, what advice would you give to people who prepare food (restaurant workers, cafeteria workers, etc.) to help prevent the spread of harmful bacteria? (Clean surfaces thoroughly, properly wash hands, and don’t cross- contaminate surfaces and foods.)
FOOD SAFETY 21 1 BACTERIA EVERYWHERE
SUMMARY RESOURCES Bacteria are everywhere and can spread from surface to surface, person to person, food to food, • Food Safety A to Z Reference Guide (See the and person to food. Harmful bacteria can be following terms — Bacteria, Cross-Contamination, controlled by practicing the 4 Cs of Food Safety. Foodborne Illness, Four Steps to Food Safety, To prevent the spread of harmful bacteria, proper Fungus, Handwashing, Microorganism, Mold, and cleaning of both hands and surfaces is especially Pathogen.) Also see the 4 Cs section beginning on important. The good thing is that not all bacteria page 54. are harmful; most bacteria are beneficial to us. • Dr. X and the Quest for Food Safety M O DWhen U L E designing experiments, you should always video/DVD Module 1 – Understanding Bacteria UNDERSTANDING BACTERIA UNDERSTANDING use safe techniques when working with bacteria. Also, it’s important to have a control plate. • Laboratory Exercises in Microbiology, 4th Edition. Harley, J., and L. Prescott. WCB McGraw- EXTENSIONS Hill: Boston, MA (1999). • Research the following questions: • Bergey’s Manual of Determinative — Is it possible to eradicate all bacteria Bacteriology, edited by John G. Holt, Ph.D., from the environment? Why or why not? 9th edition, Lippincott Williams & Wilkins, — Would this be a good idea? Why or why Philadelphia, PA (1993). Now only available in not? public or college libraries. — What essential functions do bacteria • Bergey’s Manual of Systematic Bacteriology, play in the environment? edited by David Boone, Richard Castenholz, and • Also try the following: George Garrity, 2nd edition, Volume 1, Springer Bacterial Reduction Activity Verlag, New York, NY (May 2001). Call 1-800- 1. Write a hypothesis and design an experiment Springer (777-4643). ISBN # 0-387-98771-1. to remove or reduce the amount of bacteria Springer Web site: www.springer-ny.com. on the areas where you saw bacterial growth. Test variables such as: • Web sites • Different techniques, e.g., rinsing hands The Microbe Zoo: Digital Learning Center with water versus washing with soap and for Microbial Ecology at Michigan State University/ water, versus not washing at all. Comm Tech Lab • Washing hands for different times: 10 www.comtechlab.msu.edu/sites/dlc-me/zoo/ seconds, 15 seconds, 20 seconds. What are Germs?/Kids Health • Other variables that you might suggest. www.kidshealth.org/kid/talk/qa/germs_prt.htm 2. Record your predictions on your Lab Report Why Do I Need to Wash My Hands?/Kids Health Outline. www.kidshealth.org/kid/talk/qa/ 3. Design the experiment with your team, wash_hands_prt.htm consult with your teacher for guidance, and carry out the test. Keyword: Bacteria 4. Conduct the experiment using a more Go to: www.scilinks.org Code: FS100 quantitative approach: • Swab the surface. • Transfer the swab to 10 ml of buffered saline and mix. . . . • Inoculate Petri dishes from the liquid. T EX N The worst. The baddest of P
U the bad! The 12 Most Unwanted Bacteria. CONNECTION Discover what ER E foodborne illnesses R See real-life scientists in action! they cause and A
C • www.foodsafety.gov/~fsg/teach.html how to control • Food Safety A to Z Reference Guide them.
22 FOOD SAFETY LAB REPORT OUTLINE
Name ______Date ______Class/Hour ______
(Write in complete sentences. Measure in metric.)
1. Problem (What question are you investigating?)
2. Hypothesis (What do you think will happen?)
3. Materials (List the supplies needed to conduct the experiment.)
4. Procedure (List the steps followed to complete the experiment.)
5. Data/Organization/ Interpretation (What did you see, hear, or smell? You should use a graph, chart, and/or illustration.)
6. Summary (Explain the results using science vocabulary.)
7. Further Questions (Good scientists always think of something else they’d like to try!)
FOOD SAFETY 23 BACTERIA EVERYWHERE DATA TABLE
Name ______Date ______Class/Hour ______
LAB 1 — Find the Bacteria LAB 2 — Observe and Record the Results
Choose the Hypothesize the Rank the Amount Describe the Size, Areas to Be Least/Most of Microorganisms Shape, and Colors Examined Abundant Areas 5 (most) of Organisms 0 (least)
24 FOOD SAFETY THE 12 MOST UNWANTED BACTERIA 1 Time: One 45-minute class period to set up the activity One 45-minute class period for team presentations E L U D UNDERSTANDINGBACTERIA O M
ACTIVITY AT A GLANCE FOOD SAFETY CONNECTION Students will divide into teams and select a Foodborne bacteria can have a major bacterium from The 12 Most Unwanted Bacteria impact on public health. Everyone is reproducible to research throughout the food safety susceptible to foodborne illness, especially unit. Each team will relate all subsequent activities the “at-risk” populations, including young and experiments in the unit to their bacterium and children, pregnant women, the elderly, and conduct an innovative presentation at the end of people with weakened immune systems. the unit. Each team will be able to recognize the There are four simple steps to preventing foodborne illness that their bacterium causes and foodborne illness: clean, cook, chill, and understand how to control that bacterium. combat cross-contamination. GETTING STARTED ADVANCE PREPARATION MATERIALS • Write the name of each bacterium from The 12 For the Class Most Unwanted Bacteria reproducible (page 28) • A bowl containing the names of the 12 Most on separate pieces of paper and place them in a Unwanted Bacteria bowl. Teams of students will randomly select a bacterium to study throughout the unit. • Foods, pictures, or models of foods that contain good bacteria, such as cheese and yogurt • Photocopy background material on each of the 12 Most Unwanted Bacteria from the For Each Team of Students Food Safety A to Z Reference Guide. • A food safety portfolio for recording research • Photocopy The 12 Most Unwanted Bacteria data (use a notebook or folder) reproducible for each student. • An assortment of items for final presentations • Collect actual foods, pictures, or models of • Photocopy of background information for their foods that contain good bacteria (e.g., cheese, chosen bacterium yogurt, etc.) • Photocopy of The 12 Most Unwanted Bacteria • Set a due date for the final team presentations. reproducible for each student
INTRODUCTION Ask students: What do you usually see on a • Have you ever eaten this? (Show a picture or “Most Wanted” list? Hopefully, students will a slice of cheese, and/or a container or picture respond with “bad guys” or “criminals.” Then of yogurt.) What do these foods have in hold up a copy of The 12 Most Unwanted Bacteria common? (They all contain beneficial bacteria.) reproducible and ask: Does anyone know why Can you think of some other foods that these are “unwanted”? (They’re pathogens that contain good bacteria? (Some examples: can be found in foods and can make us sick if we buttermilk, sauerkraut, pickles — even wine and eat them.) Distribute the reproducible. Continue the beer.) discussion with: • Are you surprised that these foods contain • Are any of these familiar to you? Which bacteria? Why? ones? What have you heard about them? • Where else might we find good bacteria? • Are all bacteria bad? (No, most bacteria are (Examples could include: In our small intestine beneficial to us in our everyday lives.) there’s generic E. coli, which helps us digest our • If I asked you to make a poster of “Wanted food; and in antibiotics like Streptomycin, which Bacteria,” what would you put on that helps treat patients with infections.) Explain to the poster? class: In this activity we’re going to focus on some harmful bacteria that can make us • Have you ever eaten foods that contain sick and explore why Dr. X considers these bacteria? bacteria the worst, “the baddest of the bad!”
FOOD SAFETY 25 1 THE 12 MOST UNWANTED BACTERIA
PROCEDURE
1. Divide students into 12 teams. Have a person Ideas for Final Presentations from each team select a pathogen from the bowl. Perform 2. Ask the students what they’d like to know about • Perform a skit using your pathogen as the main bacteria in order to become “super science character. sleuths.” Write their answers on the board. • Dress up as your pathogen and perform a moving 3. Give a food safety portfolio to each team. monologue. Challenge them to be constantly on the lookout M O D U L E • Create a poem, song, dance, or rap about your for information about their pathogen and to UNDERSTANDING BACTERIA UNDERSTANDING mighty microbe. record their findings in their portfolio. Remind them to include the date, URL for Web sites, • Produce “Jeopardy” or “Who Wants to Be a title, author, year, and page numbers of books Millionaire?” type game shows. or articles. • Put on a news broadcast about a real outbreak 4. Have each team divide the questions on The 12 involving your pathogen. Most Unwanted Bacteria reproducible equally • Put on a puppet show or create picture books to among members of their team, so that everyone share with primary school students. in the group has a task. The reproducible can Design be used as a checklist during their research. • Prepare posters or 3-D models of your pathogen 5. Give each team background material on their to hang around the classroom, using assorted selected pathogen from the Food Safety A to Z materials (coat hangers, newspapers, papier Reference Guide to get them started. mâché, balloons, cardboard, plastic bottles, poster 6. Explain that each group will work together to: board, fabric scraps, pipe cleaners, and beads). • Conduct in-depth research about their pathogen. • Design a food safety calendar with a theme for • Find out how their pathogen makes an impact on removing or eliminating your pathogen for each food safety along the Farm-to-Table Continuum. month of the year. • Discover what can be done to control the • Design and prepare Web pages that offer photos growth of their pathogen. and facts about your pathogen. • Present their research to the class to teach • Develop an animated slide show, using Power Point other students about their pathogen. Give slides and clay animation. students a date for their presentations. • Design a travel brochure with graphics and text tracing the journey of your pathogen. Planning the Final Presentation • Create an animated flip book about your microbe. 1. Explain to the class that at the end of the Write food safety unit, each team will present their • Interview your pathogen like Dr. X did in the video. research to the class in a fun, creative way. • Write humorous comic strips featuring your The presentation should be a maximum of pathogen. 5 minutes. Students can use the following suggestions or come up with their own ideas. • Create a recipe book filled with food safety tips for avoiding your pathogen. 2. Since one of the purposes of the presentation is to share what they learned about their bacterium • Write a moving story about a day in the life of your with the other students, each team should pathogen. prepare a simple fact sheet on their bacterium Create Video for the other teams to add to their portfolios. At • Create a video pertaining to your pathogen using the end of the presentations, each team will have one of the following styles – documentary, news- information on all the 12 Most Unwanted Bacteria. cast, drama, advertisement, or game show.
• After completing each activity and experiment in this food safety unit, remind the teams to add what they’ve learned about their bacterium to their food safety portfolio. Encourage them to also include information they’ve discovered from TIPS their own research. • Throughout the unit, periodically check the students’ food safety portfolios to evaluate their progress and give guidance on additional research.
26 FOOD SAFETY THE 12 MOST UNWANTED BACTERIA 1 E L U D UNDERSTANDINGBACTERIA O M SUMMARY RESOURCES A pathogen is any microorganism that is • Food Safety A to Z Reference Guide infectious and causes disease. There are bad (See the following terms — Bacteria, Farm- bacteria (pathogens), such as the 12 Most to-Table Continuum, Foodborne Illness, Four Unwanted Bacteria, that cause foodborne illness. Steps to Food Safety, and Pathogen — refer to However, not all bacteria are bad. Good bacteria, The 12 Most Unwanted Bacteria list.) such as those found in foods like yogurt and • Dr. X and the Quest for Food Safety video pickles, and those in antibiotics like Streptomycin, /DVD Module 1 — Understanding Bacteria are helpful to us. • Web sites: EXTENSIONS Cells Alive • Be on the lookout for reports about your www.cellsalive.net pathogen in local newspapers, on TV news CDC reports, and on the Internet. These newsworthy www.cdc.gov/foodsafety reports can be added to your food safety www.cdc.gov/ncidod/dbmd/diseaseinfo/ portfolios. The FDA Bad Bug Book http://www.cfsan.fda. • Take a virtual field trip to the American gov/~mow/intro.html Museum of Natural History’s “Epidemic! The Iowa State University Food Safety Project www. World of Infectious Disease” at www.amnh.org/ extension.iastate.edu/foodsafety exhibitions/epidemic/index.html Microbe World/American Society for
Microbiology www.microbeworld.org Partnership for Food Safety Education www.fightbac.org CONNECTION ER E R See real-life scientists in action! Keyword: Foodborne Illnesses A Go to: www.scilinks.org C • www.foodsafety.gov/~fsg/teach.html Code: FS301 • Food Safety A to Z Reference Guide
. . T . EX N Put on your boots! We’re going P
U to the farm with Dr. X to meet his scientist friends who will introduce us to the first step in the Farm-to-Table Continuum.
FOOD SAFETY 27 The 12 “MOST “MOST UNWANTED”UNWANTED” Bacteria
UNWANTED UNWANTED UNWANTED UNWANTED Audrey Wagner, Ph.D., Audrey Wagner, Medical University School of Texas Lan Hu, Ph.D., Dennis J. Kopecko, Ph.D., and Ph.D. Ben Tall, Campylobacter Clostridium Clostridium Escherichia coli O157:H7 jejuni botulinum perfringens (a.k.a. E. coli O157:H7)
UNWANTED UNWANTED UNWANTED UNWANTED
Listeria Salmonella Salmonella Shigella monocytogenes Enteritidis Typhimurium
UNWANTED UNWANTED UNWANTED UNWANTED
Staphylococcus Vibrio cholerae Vibrio vulnificus Yersinia aureus enterocolitica
BE ON THE LOOKOUT FOR ONE OF THESE CREEPY CRITTERS. Here are some questions that will help you develop a profile on your bad bug.
NAME OF BACTERIUM (Pathogen): —————————————————————————— ____ What does it need to thrive? ____ What are the foods/sources associated with it and possible contaminants? ____ What is the implicated illness? ____ What is the incubation period for the illness? ____ What are the symptoms associated with the illness? ____ What is the duration of the symptoms? ____ What are the steps for prevention? ____ Draw a picture or make a model of your bacterium. ____ What is your bacterium’s implication in the Farm-to-Table Continuum? (how your bacterium can spread and how it can be prevented at each step) _____ Farm _____ Processing _____ Transportation _____ Retail _____ Home (table) FARM 2 E L U D O M ABOUT THE MODULE Module 2 — Farm — Who’s responsible for food safety? It’s everyone’s responsibility, from the farmers who grow the food to the people who place the food on your table. Chain of Food — explores the path food takes along the Farm-to-Table Continuum.
SCIENCE CONTENT
This section explains the specific science concepts presented in Module 2 of the video/DVD, including fascinating facts relative to the module. Read this section before watching the video module or conducting the activities and experiments.
FARM There are many places on a farm that can be contaminated by harmful bacteria, so farmers have to make sure that the areas where food is handled are kept clean and at the right temperature. There are many innovations on the farm that help prevent the growth of bacteria — like special areas for washing vegetables, refrigerated storage areas for milk and eggs, and portable sanitation in fields.
Competitive Exclusion Salmonella is a foodborne pathogen sometimes found in the intestines of chickens. It can be passed on in the meat and also in the chicken’s eggs. The best way to reduce the risk of foodborne illness from eating contaminated chicken is to prevent the Salmonella from living in the animal in the first place. Dr. Theodore Elsasser explains competitive exclusion. Using a process called competitive exclusion, chickens ingest a blend of good bacteria, which ultimately shields them from pathogenic Salmonella microbes.
Young mammals are born with undeveloped gastrointestinal tracts. It’s fertile ground for both good and bad bacteria. Whichever organisms get introduced to their systems first will take over.
Scientists developed mixtures of beneficial bacteria to prevent bad bacteria, like Salmonella, from colonizing and infecting the chickens. To make it work, scientists use a blend of non- pathogenic bacteria naturally found in the gastrointestinal tract of mature chickens and spray it on day-old chicks. Through the Chickens being sprayed with natural interactions of the chickens grooming each other, the good bacteria. bacteria enter their intestinal tracks.
Competitive Exclusion results in naturally disease-resistant, mature, healthy birds — making it virtually impossible for Salmonella to multiply. It also reduces Salmonella in the environment because there are fewer infected birds to contaminate the farm.
FOOD SAFETY 29 2 SCIENCE CONTENT
Composting to Kill E. Coli: FARM Another way farmers keep down the spread of bacteria is through composting.
Compost is actually made up of the decomposed parts of all the residuals that come from the farm operation — the waste from the animals, leftover food the animals didn’t eat, hay/straw, etc. It all gets mixed together and heaped up so that the microbes can eat it
M O D U L E and create compost, which the farmers use to fertilize their crops.
The microbes are basically getting a workout from eating all of the Compost fields at the USDA organic materials. As the microbes work at digesting the wastes Agricultural Research Service in in the compost, the temperature of the compost rises. The heat Beltsville, MD plays an important role because E. coli O157:H7 can’t survive in temperatures above 131° F (55° C).
E. coli may be found in the manure that is used in the compost. So farmers have to be very careful about cross-contamination when the compost is used on any crops, but the risk may be greatest for low-growing crops, such as lettuce and strawberries.
Scientists are working to develop ways for farmers to assure that their compost reaches high enough temperatures to kill pathogens and make the compost safe for their crops. Note: This is still in Dr. Patricia Millner discusses the research stage. composting research.
FASCINATING S T C A F
Microbes eating the organic materials in the compost heat up so much that they actually cook themselves.
30 FOOD SAFETY 2
CHAIN OF FOOD E L U D FARM O M Time: One 45-minute class period
ACTIVITY AT A GLANCE FOOD SAFETY CONNECTION Students will explore the path food takes along the Everyone along the Farm-to-Table Continuum Farm –to–Table Continuum. They will begin on the plays a major role in keeping our food safe. If farm, and throughout the unit they will investigate a link in this continuum is broken, the safety food safety issues during processing, transportation, and integrity of our nation’s food supply can at restaurants and supermarkets, and finally, in be threatened. their own homes. Teams will identify how food can become contaminated along the continuum and develop and present strategies for preventing contamination at each step.
GETTING STARTED MATERIALS ADVANCED PREPARATION • Dr. X and the Quest for Food Safety video/DVD, Put the grated cheese and relish on top of the Module 2 — Farm cooked hot dog in the bun. Place the hot dog and • Food Safety A to Z Reference Guide (page 15 the banana on a paper plate and set the plate where [Farm-to-Table Continuum], page 16 [Farm-to- the students will see it when they enter the room. Table Initiative]), and Food Safety Farm-to-Table Illustration, pages 52–53 Use food specific to your region or to the • Cooked hot dog on a bun tastes of your students. Just make sure that a T I P • Grated cheese variety of food groups and types are represented — meat, dairy, fruits or • Relish vegetables, fresh, processed, cooked, local • Banana products, imported foods, etc. • Paper plate • Poster board STUDENTS SHOULD NOT EAT ANY FOOD USED • Markers IN AN ACTIVITY OR EXPERIMENT.
INTRODUCTION
Look surprised when someone mentions the • Tell the students: In the next few activities, hot dog or banana. Then go over, pick up the you’ll learn about people you never dreamed hot dog and banana and ask: Does anyone had a role in getting this food to you. know where these foods came from? Let • What does science have to do with the the students speculate for a few minutes. Then farm? Give the students time to make a few comment: I confess, I put them there, but suggestions. let’s look at who else played a part in • Then ask: What do you think could happen getting the hot dog, bun, cheese, relish, to food along the Farm-to-Table Continuum and banana to us. Allow the students to that could affect the safety of our food review the Farm-to-Table Continuum steps (farm, supply? List their answers on the board. processing, transportation, retail, and home) they learned in The Big Picture activity (Module 1). • Food doesn’t start at the supermarket or restaurant. Today, we’ll trace the path of food along the Farm-to-Table Continuum and discover some of the ways it can become contaminated. Then we’ll develop and present strategies for preventing contamination at each step.
FOOD SAFETY 31 2 CHAIN OF FOOD
TIME TO TUNE IN . . . Module 2 — Farm FARM Let’s tune in to the first step on the Farm-to-Table Continuum. While watching this module, keep these questions in mind: • Would you feed a baby chick bacteria? Why or why not? • What’s compost all about, and how is it relevant to food safety on the farm? Tune in, and take notes. Show video/DVD Module 2 — Farm (Time: 4 minutes). M O D U L E INSTANT REPLAY Time to review and summarize.
1. Why did Dr. Elsasser feed a baby chick bacteria? (Good bacteria are fed to baby chicks, so there is no room left for the bad bacteria to grow.) 2. What did you find interesting about Dr. Elsasser’s job? 3. We also met Dr. Patricia Millner, another scientist who conducts research for keeping our food safe on the farm. What did she say about compost, and how is it relevant to food safety on the farm? (It’s heat again. If enough heat can be generated from the compost, it will kill harmful bacteria, especially E. coli O157:H7. The compost is then safe to use on crops that we will eat.) 4. How does Dr. Millner’s research benefit us? (It will help keep our food safe.)
PROCEDURE
1. Divide the class into 5 groups. Assign a food to 5. For each person the team identifies, they must each group (hot dog, bun, cheese, relish, and include what that person does to help control banana). the spread of bacteria. Students should label 2. Have students begin researching their food. all the places where contamination of their food Using poster board, let each team trace their may occur, then write a strategy for preventing food from the farm to the table. This will serve that particular contamination. Use the 4 Cs as the “first draft” of their food journey chart. to help develop the strategy. For example, in Remind students that some foods are imported the video they learned about the potential from other countries, so be sure to trace them contamination of crops at the farm — the from their origin. (Students can find out where compost must reach at least 131° F (55° C) to a variety of foods come from by visiting the ensure that the compost doesn’t contaminate Economic Research site at www.ers.usda.gov/ the crops. One suggestion could be to develop db/fatus.) ways for compost to reach high enough temperatures to kill pathogenic bacteria and to 3. Post the charts around the classroom, and keep make the compost safe. them up during the unit. As the teams learn more about the continuum, they can add to or 6. At the end of Module 4, have each team share change the information. their food journey chart with the class. The team that traces the banana should also 4. Challenge the students to include all the people address the global issue. Ask students: What involved at each step (e.g., farmers, produce do these foods have in common? Where pickers, milkers, truckers, grocery workers, do the similarities and differences occur shelf stockers, restaurant workers, etc.). Create along the Farm-to-Table Continuum? a competition that focuses on which team can identify the most people. This challenge comes 7. Have each team add up the number of people in #5. they identified. Which food had the most people involved in the Farm-to-Table Continuum? Why?
32 FOOD SAFETY CHAIN OF FOOD 2 E L U D FARM O M
SUMMARY RESOURCES Everyone along the Farm-to-Table Continuum plays a role in keeping our food safe from harmful • Food Safety A to Z Reference Guide bacteria. If a link in this continuum is broken, the (See the following terms — Bacteria, safety of our nation’s food supply is at risk. There Competitive Exclusion, Composting, are food safety precautions, including the 4 Cs of Contamination, Cross-Contamination, Food Safety, that help prevent contamination of Escherichia coli O157:H7, Farm-to-Table food at each step. Continuum, Farm-to-Table Initiative, Foodborne Illness, Food Safety, and Pathogen.) Also see the Farm-to-Table illustration (pages EXTENSIONS 52–53) and the 4 Cs section (pages 54–63). • Visit the Economic Research Service Web site at www.ers.usda.gov/data/fatus, find your favorite • Dr. X and the Quest for Food Safety video/ food, and see how many different countries it DVD Module 2 – Farm comes from. Or, select a country and see how many foods we get from that country. • Web site • Using the Web site above, look on a map and Economic Research Service/USDA calculate how many miles your favorite food www.ers.usda.gov/data/fatus traveled from one of the countries to your state. For example, how many miles did the banana travel from where it was grown to your state? • Relate your pathogen to this experiment and record the information in your food safety portfolio.
. CONNECTION . . R T E X E E Ever heard of R See real-life scientists in action! N methylene blue? A C • www.foodsafety.gov/~fsg/teach.html P Well, it’s a clue to a • Food Safety A to Z Reference Guide U very important concept in pasteurization technology. You’ll discover the clue in the next lab experiment as you, along with Dr. X and Tracy, explore Processing — the next step along the Farm-to-Table Continuum.
FOOD SAFETY 33 3 PROCESSING AND TRANSPORTATION ABOUT THE MODULE Module 3 — Processing and Transportation — Did you know that there are many ways to control bacteria during processing and transportation? This module focuses on several methods scientists use to keep our food safe. Blue’s the Clue — introduces pasteurization and the effect temperature has on reducing and controlling the growth of bacteria. Mystery Juice — uses investigation to demonstrate how pasteurization reduces the number of microorganisms in juice.
M O D U L E Ultra High Pressure Treatment — shows how foods are kept safe through processing, including the newest food preservation technology.
SCIENCE CONTENT
This section explains the specific science concepts presented in Module 3 of the video/DVD, including fascinating facts relative to the module. Read this section before watching the video module or conducting the activities and experiments.
PROCESSING
Food safety plays a major role throughout food processing.
Pasteurization Pasteurization is the process of using heat or irradiation to destroy microorganisms that could cause disease. Modern dairy farms today may have up to 5,000 cows. All the milk is pooled, so if one cow is sick, there is a possibility to contaminate all the milk. That’s why milk is pasteurized. Milk was one of the first products to be pasteurized on a broad scale. Dr. Charles Sizer discusses In addition to dairy products, other pasteurized foods include fruit pasteurization. juices, chicken, beef, and spices. One challenge scientists had was trying to figure out how to pasteurize an egg without cooking it. The solution was to heat the eggs up slowly to 57° C and maintain that temperature for 1 hour and 15 minutes. This time/temperature relationship inactivates the bacteria while keeping the eggs fluid. Louis Pasteur (1822–1895), a chemist, was actually trying to prevent spoilage in wine and beer when he discovered pasteurization. Pasteurization was applied first in wine preservation. When milk producers adopted the process, it substantially reduced foodborne FASCINATING S T C A F illness. You never know where science will lead you! More than 1,000 Time/Temperature Relationship different types of food are pasteurized. Traditional pasteurization is achieved by exposing foods to heat for a certain length of time. Bacteria are very heat-sensitive, and the higher the temperature, the quicker they can be inactivated. Using higher heat takes less time to kill pathogenic bacteria, whereas using lower heat takes more time.
34 FOOD SAFETY 3 M O D U L E PROCESSING AND TRANSPORTATION 35 . .
SCIENCE CONTENT SCIENCE FOOD SAFETY and Combat Cross-Contamination Clean, Cook, Chill, cold chain has to be maintained throughout the loading process, Proper packaging is selected for the product. The shipping container is cleaned and properly loaded, making sure that the boxes are stacked tightly to lock in the cold during transit. Refrigerated by satellites. be tracked can control temperature Proper records automatically that equipment have usually containers the inside temperature air the and functions system refrigeration of refrigeration record a detailed provides information This container. trip. the during performance system Food is properly stored and cooled at the warehouse. The in transit, and during receiving. plant. or field the from comes it as precooled and cleaned is food The ripening, of rate heat, field reducing by life product extends cooling The decay of spread the and respiration, of rate moisture, of loss Irradiation Irradiation is the process in which ionizing energy is used to kill foodborne pathogens. During irradiation, an intense pulse of energy is emitted, either from a gamma radiation source like Cobalt 60 or from an electrical source like an electron beam accelerator. The energy penetrates the food and destroys any bacteria. the repair can it Unless DNA. microbe’s the damages Irradiation duplicate to tries and grows it when die will microbe the damage, itself. Today, some food producers are beginning to use a new method for killing harmful bacteria in foods that contain water. It’s called ultra high pressure (UHP) treatment. This process destroys bacteria without the use of high temperatures or chemical additives. Thus, foods such as juices, salsas, cold-cuts, and other moist foods, are made safer while the vitamins, flavor, and freshness of the foods are maintained. Using specially designed equipment, the food is subjected to 50,000 to 100,000 pounds of pressure per square inch. This ultra high pressure is maintained from 30 seconds to a few minutes depending on the food. The ultra high pressure interferes with the metabolism and structure of bacteria and destroys these living cells without altering the basic composition of the food. Important Note: Despite pasteurization, irradiation, and ultra high pressure (UHP) treatment, food can still become contaminated if the basic rules of food safety are not followed all along the Farm–to- Table Continuum. It’s important to always follow the 4 Cs of Food Safety: The 4 Cs of Food Safety play a very prominent role in transportation. transportation. in role prominent a very play Safety Food of 4 Cs The the across shipped it’s as condition good in and safe food Keeping to steps many are There critical. is world the around or country step. each behind science there’s and safely food shipping Ultra High Pressure (UHP) Treatment Irradiation TRANSPORTATION
Iowa State University Extension University State Iowa FACTS Two elephants balancing on balancing elephants Two to is equivalent dime a thin psi. 60,000 FASCINATING Dr. Sizer demonstrates ultra high pressure treatment. Using gamma rays to destroy bacteria Proper packaging is selected for the product. M O D U L E 3 36 PROCESSING AND TRANSPORTATION • • compartment, freezer with Refrigerator • depending racks, test-tube 6 • to 3 Class the For MATERIALS Photocopy the Photocopy • (Pasteurization), 31–33 pages Photocopy • table. lab a on equipment the all Place • high ultra and milk whole pasteurized Purchase • and pipettes, caps, test-tube tubes, test the Sterilize • • blue. methylene Order • ADVANCE PREPARATION GETTING STARTED
Mix 1 ml of methyleneofml Mix1 bluesolution1% water.ofml25in about the importancepasteurizationtheaboutof keeping safe. foodin spoilagelearnbacteria.growthofalsoaffectwillthe They temperaturestemperature,(heat,room chilling, freezing)and temperaturehighdifferentobservehowandmilk, (UHT) transportation.pasteurizedStudentsuseultrawill and temperaturereducingcontrollingandongrowthof the of effect the to students introduces experiment This LAB ATAGLANCE Y T E F A S D O O F (See the pages above.) pages the (See and Transportation Transportation and if possible if racks. test-tube share can Teams teams. of number the on video Dr. X and the Quest for Food Safety Food for Quest the and X Dr. Guide Reference Z to A Safety Food Treatment) of the of Treatment) each team. each store manager to order it if it isn’t available in your in available isn’t it if it order to manager store your Ask aisle. juice the in found be usually can milk stable (Shelf milk. whole stable) (shelf temperature 9.) page (See bulbs. pipette (Shelf Stable), and Stable), (Shelf supermarket.) #S71326). catalog — Scientific Fisher from Solution Aqueous Reagent (Educational 1% chloride blue methylene using designed was experiment This Note: , Module 3 — Processing — 3 Module /DVD, One 45-minute class period, plus observation time over the next 2 to 3 days 3 to 2 next the over time observation plus period, class 45-minute Time:One THE CLUE BLUE’S Blue’s the Clue the Blue’s
Food Safety A to Z Reference Guide. Reference Z to A Safety Food page 46 (Ultra High Pressure High (Ultra 46
(page 41) for 41) (page Table Data
page For Each Team of 3 to 4 Students 4 to 3 of Team Each For • tubes test label to • marker Permanent aids pipette or bulbs • pipette Sterile droppers eye or pipettes ml 5 sterile two • or One pipettes ml 10 • sterile Two the cover to foil aluminum or caps test-tube • sterile 6 tubes test • sterile 6 tube) test per drop (1 solution dilute • blue Methylene milk whole stable) (shelf temperature high ultra of ml 60 • tube) ml/test (10 milk whole pasteurized, of • ml 60
test tubes test tube) ml/test (10 Blue’s the Clue Data Table Data Clue the Blue’s 41 a and be stored without refrigeration for up to up for refrigeration without stored be can and milk, pasteurized conventionally than bacteria fewer contains milk UHT packaging, special and heat high the of Because containers. airtight sterile, in (138° C) for C) (138° F 280° least at to heated is milk UHT MILK PASTEURIZED AND UHT ABOUT bacteria. however, it may not kill all the spoilage the all kill not may it however, milk; in found bacteria pathogenic the kills process This seconds. 15 for C) (72° F 161° least at to heated is milk Pasteurized milk. pasteurized like just refrigerated be should it opening, after Therefore, milk. pasteurized milk is similar to that of conventionally of that to similar is milk UHT for time spoilage opening, After days. FOOD SAFETY CONNECTION FOOD SAFETY bacterial growth. bacterial reduce help to home at food store and prepare they how to findings these relate to able be will students growth, bacterial on temperature of effect the about learning By
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3 M O D U L E PROCESSING AND TRANSPORTATION
37
BLUE’S BLUE’S CLUE THE FOOD SAFETY (Pasteurized milk is heated for a longer a longer for heated is milk (Pasteurized test tubes and other materials in hot, FIRST
/DVD Module 3 — Processing and soapy water after the lab. Caution: Be careful not to spill methylene blue on the countertops or clothes; it may stain. bulb or aid. hot, soapy water. • DO NOT DRINK THE MILK USED IN THE LAB. Never pipette by • mouth. Always use a pipette Wash • Before leaving the • lab, wash your hands with SAFETY processing? without cooking it? being refrigerated? have to do with food safety and food
What is pasteurization? How can an egg be pasteurized in the shell How can some types of milk stay safe without What process keeps food safe in outer space? What do cows, astronauts, and elephants
Transportation (Time: 7 minutes). Show video • • • • • : (Manufacturers use a time/temperature relationship to pasteurize pasteurize to relationship a time/temperature use (Manufacturers
Module 3 — Processing Transportation and /DVD
Time Time to review and summarize. time at a lower temperature, and UHT milk is heated for less time at a higher temperature.) a higher at time less for heated is milk UHT and temperature, a lower at time eggs in the shell without cooking them. Heating eggs above 140° F [60° C] will cook them. them. cook will C] F [60° 140° above eggs Heating them. cooking without shell the in eggs bacteria kills minutes, 45 time, a long for C] F [54° 130° of temperature a lower using Thus, cooking.) without (Irradiation of their food) (UHT milk contains fewer bacteria than conventionally pasteurized milk because it’s heated to a higher temperature. It’s also packaged in sterile, airtight containers. Therefore, UHT milk can be stored without refrigeration for up to 90 days.) So So . . in . illness from foodborne outer getting space? what astronauts prevents How can an egg be pasteurized in the shell without cooking the egg or breaking the shell? How can some types of milk stay fresh and safe without being refrigerated? What is pasteurization? (Pasteurization uses heat to kill harmful bacteria in foods.) What is the time/temperature relationship? What’s the relevance of cows, astronauts, and elephants to food safety and food processing? (Cows refer to pasteurization, astronauts refer to irradiation, and elephants refer to ultra high pressure treatment.)
Introduce the video by explaining that on our next stop along the Farm-to-Table-Continuum, students are going to learn about Processing. Dr. X will beam them into the research lab of one of his scientist friends who looks at new ways to reduce the bacteria in our food through processing. Here are some things to think about while they watch the video TIME TO TUNE IN . . . 6. 4. 5. 2. 3. 1. Bacteria, Dr. X talked about the Danger Zone. What precautions did he give about the “Zone”? What might be present in milk that has been left in the Danger Zone for more than 2 hours? parents are always asking you to put the milk back in the refrigerator? What might happen to that milk if it’s left out at room temperature overnight? INTRODUCTION INSTANT REPLAY INSTANT • In the video Module 1 — Understanding • Have you ever wondered why your Explain to students that later in Module 3, they’ll learn more about ultra high pressure treatment, but in this activity, they’ll focus on pasteurization. Now ask students: 3 BLUE’S THE CLUE
PROCEDURE
LAB 1 Design and Conduct Experiment
1. Ask students to form teams of 3 or 4 and • What are the similarities and differences encourage each team to develop a hypothesis between pasteurized and ultra high on how temperature affects bacterial growth. temperature treatments? (Both pasteurization Then ask them to design an experiment to test and ultra high temperature use heat to kill
M O D Utheir L E hypothesis. bacteria. Ultra high temperature methods use 2. Introduce the three materials teams must use higher temperatures than regular pasteurization. for their experiment: regular pasteurized milk, Also, products treated at ultra high temperatures ultra high temperature (shelf stable) milk, and are packaged in special airtight containers to methylene blue. prevent bacteria from getting into the product.) PROCESSING AND TRANSPORTATION 3. Ask: How might you use methylene blue to • Could there be differences in the growth help with your experiment? Students can of bacteria between the two milks? What research methylene blue and discover that it’s do you think the differences might be? an indicator dye used to determine the presence (The regular pasteurized milk should show of bacteria in milk. Tell them they can use any bacterial growth sooner than the UHT milk of the other materials on the lab table. Also, because the pasteurized milk has more bacteria there’s a refrigerator and freezer they can use. in it.) 4. Let teams discuss their hypotheses and • Should you consider these differences experimental designs for 10 to 15 minutes. when you design your experiments? Then, begin posing the following questions Why? (Yes, both milks should be tested in all to help students design well-thought-out conditions.) experiments: • How can you tell if bacteria are growing • What are some ways you could test in the test samples? (Add methylene blue the effect of temperature on bacteria? to each sample. If bacteria are growing, the What did you learn about the effect of methylene blue will become colorless and the temperature on bacteria in Module 1 milk will change from blue to white. This is not — Understanding Bacteria of the video/ immediate, but happens over time.) DVD? (Heating is a way to kill bacteria, 5. Have each group present their hypothesis and whereas chilling and freezing are ways to experimental design to the class. Encourage retard the growth of bacteria.) students to discuss the merits of each suggested • Explain that one container of milk came from test. (One effective experimental design is to the refrigerated dairy case of the supermarket test pasteurized milk and UHT milk at three and the other from an unrefrigerated shelf. temperatures — room temperature, chilled, and Let students examine each container. frozen.) • What’s an important difference between 6. After the group discussions, give the teams time to the two milk products? Is there any revise their hypotheses and experimental designs. information on the labels that relates 7. Let teams conduct experiments according to our question about the effect of to their designs. Note: The test tubes must temperature on bacterial growth? be checked each day after the experiment is (Students should discover that one is conducted. Since the color change happens over pasteurized and the other is treated using time, you could miss important findings if you ultra high temperature.) don’t check every day.
About Methylene Blue • Carefully label all test tubes and test-tube Methylene blue is an indicator dye that, in racks.
anaerobic conditions, becomes colorless and TIPS• The methylene blue will mix better if the is reduced to leucomethylene. Methylene blue milk is added to the test tubes before the loses its color in the absence of oxygen because methylene blue. Mix thoroughly by lightly bacteria use up the oxygen present in the milk. tapping the test tubes with your fingers. The rate at which it loses its color is a relative • Gas will be produced, so don’t close the measure of bacteria present in milk. test-tube caps tightly.
38 FOOD SAFETY BLUE’S THE CLUE 3 E L U D TRANSPORTATIONAND PROCESSING O M LAB 2 Observe and Record
Option: Students can use the Blue’s the Clue Data temperature and remain in the Danger Zone Table to record their results. for several hours, the bacteria will begin to 1. Students should observe and record the time grow. As this happens, the methylene blue will and any visual changes on day two of this lab become colorless and the milk will change from activity. Ask: How did the data support blue to white. Observe and record the results.) or reject your hypothesis? What might 2. What might happen if the UHT samples happen if the chilled and frozen samples were left out at room temperature for were left out at room temperature for another day? (If you let the UHT samples sit several hours or overnight? Should we out at room temperature for another day or test them to find out? (Yes, let the chilled more, the color will change to white. Observe
and frozen samples stand at room temperature and record the results.) until the following day. As they reach room
LAB 3 Observe, Record, and Report
1. Observe and record findings on the third day. Ask students: What happened to the frozen F • A • Q and chilled samples? What happened to If bacteria in UHT milk don’t grow the UHT samples? rapidly, why do I have to keep the milk 2. Give students 5 to 10 minutes to complete their refrigerated after I open it? Data Table. Because there are fewer bacteria in UHT milk 3. Have teams present their findings to the class. than in regular pasteurized milk, the spoilage They should report both positive and negative bacteria in UHT milk take longer to grow. results and discuss ways they would improve However, they will eventually multiply. You their experimental design. should always practice the safest precautions. Therefore, refrigerate the milk as soon as it is 4. Remind students to include the relationship of opened. their findings to food safety.
To find the results you can expect from this experiment, see page 40. TIP
INSTANT REPLAY Time to review and summarize.
1. Were bacteria killed at the different temperatures? Why or why not? How could you tell? (No. Only heat kills bacteria. Room temperature isn’t high enough to kill bacteria, and chilling and freezing do not kill bacteria, they just slow their growth. When the chilled and frozen milk reached room temperature, bacteria began to grow again.) 2. What’s a basic difference between conventionally pasteurized and UHT milk? (UHT milk can be stored on a shelf without refrigeration for up to 90 days.) 3. Explain the importance of knowing about the Danger Zone in food safety. (Awareness of the Danger Zone helps people understand the importance of heating and chilling food, thus decreasing the amount of foodborne illness.) 4. What do chilling, freezing, and heating do to bacteria? (Chilling and freezing slow down the growth, but heating kills the bacteria.)
FOOD SAFETY 39 3 BLUE’S THE CLUE
Here are the results you can expect from this experiment:
Room temperature samples Chilled and frozen samples • The pasteurized milk will turn white by Lab 2 • Both the pasteurized and UHT chilled and (day 2), indicating that there are some spoilage frozen milk samples will still be blue by bacteria in the milk. At a temperature conducive Lab 2 (day 2), indicating that cold to bacterial growth, they will multiply. temperatures retard bacterial growth. • The UHT milk will still be blue by Lab 2 (day 2). • After leaving the chilled and frozen samples This is because the UHT milk has fewer spoilage at room temperature for another day or
M O D U Lbacteria E than regular pasteurized milk. Thus, it two, the color will change to white. This takes longer to see any bacterial growth. Bacteria indicates that when the temperature rises do not quickly multiply in the UHT milk. into the Danger Zone (room temperature), • After leaving the UHT milk at room temperature bacteria can grow. It may take longer for for another day or two, the color will turn white, the UHT milk to change to white because PROCESSING AND TRANSPORTATION indicating that spoilage bacteria will ultimately there are fewer spoilage bacteria in UHT grow in the UHT milk. milk than in regular pasteurized milk.
SUMMARY RESOURCES Temperature affects the growth of bacteria. Heating • Food Safety A to Z Reference Guide kills bacteria and chilling or freezing retards the (See the following terms — Bacteria, Danger growth of bacteria. Pasteurization is the process Zone, Methylene Blue, and Pasteurization.) of destroying harmful bacteria that could cause disease by applying heat to a food; however, some • Dr. X and the Quest for Food Safety spoilage bacteria may still be present. Bacteria video/DVD Module 3 – Processing and grow more quickly in regular pasteurized milk Transportation than in UHT milk because the latter uses higher temperatures, thus killing more bacteria. Also, • Laboratory Exercises for Microbiology, UHT milk is sealed in sterile, airtight containers. by John P. Harley and Lansing M. Prescott, 4th Edition, WCB McGraw-Hill: Boston, EXTENSIONS 1999 (for additional information on • Test UHT milk that has an expiration date that methylene blue) has passed and UHT milk that has an expiration date in the future. See if the “expired” milk • Web sites changes more quickly than the fresher milk. Pasteurization — Dairy Science and Technology/University of Guelph, Canada • Try this experiment using a variety of milk forms: www.foodsci.uoguelph.ca/dairyedu/ powdered, skim, 1%, 2%, etc. pasteurization.html • Relate your pathogen to this experiment and record the information in your food safety National Milk Producers Federation portfolio. www.nmpf.org
Keyword: Pasteurization Go to: www.scilinks.org CONNECTION Code: FS302 ER E R See real-life scientists in action! A . . C • www.foodsafety.gov/~fsg/teach.html T . EX • Food Safety A to Z Reference Guide It’s time for N P you to solve U a mystery! In the next activity, we’ll work in the lab to uncover all the juicy details.
40 FOOD SAFETY BLUE’S THE CLUE DATA TABLE
Name ______Date ______Class/Hour ______
Day 1 Day 2 Day 3 Day 4 Original Sample Describe Visual Changes Describe Visual Changes Describe Visual Changes
Room Pasteurized: Pasteurized: Pasteurized: Temperature
UHT: UHT: UHT: Pasteurized UHT Milk Milk
Refrigerated Pasteurized: Pasteurized: Pasteurized:
UHT: UHT UHT: Pasteurized UHT Milk Milk
Frozen Pasteurized: Pasteurized: Pasteurized:
UHT: UHT UHT: Pasteurized UHT Milk Milk
1. How did the data support or reject your hypothesis?
2. What do you predict will happen if the chilled and frozen samples are left out at room temperature for another day?
3. What do you predict will happen if the UHT samples are left at room temperature for another day?
4. Explain the relationship of your findings to food safety.
FOOD SAFETY 41 M O D U L E 3 42 PROCESSING AND TRANSPORTATION Keep the containers closed and refrigerated until refrigerated and closed containers the Keep • cups 2 to 1 in pour and “B,” container other the Mark • of cups 2 to 1 in pour and “A,” container one Mark • • can you available, not is juice unpasteurized If • and pasteurized find and “scouting” juice some Do • ADVANCE PREPARATION GETTING STARTED must have this warning on the label: the on warning this have must juice Unpasteurized markets. farm or mills, cider stores, health-food or grocery of sections refrigerated the in found be may juice Unpasteurized JUICE UNPASTEURIZED FIND TO WHERE
Y T E F A S D O O F such as juice. as such food a in microorganisms of number the reduces pasteurization how discover to opportunity the have will Students investigations. the of results the to relation in discussed be will safety Food juices. two between difference the determine to investigation an develop will students approach, inquiry an Using LAB ATAGLANCE class time. class the of the below). (see own your prepare well.) work juice apple pasteurized and cider apple unpasteurized available, (If fruit. of type same the from made juice unpasteurized lids. Wash and sterilize the jars and lids (see page 9). page (see lids and jars the sterilize and Wash lids. have that containers clear other or jars pint 2 Use weakened immune systems. immune weakened with persons and elderly, the children, in illness serious cause can that bacteria harmful contain may therefore, and pasteurized been not has product This WARNING: juice. Close the lid. the Close juice. unpasteurized juice. Close the lid. the Close juice. pasteurized Three 45-minute class periods class 45-minute Three Time: JUICE MYSTERY
juices look identical, or at least similar. least at or identical, look juices two the if students the for intriguing more It’s pasteurized. Put pits. or seeds any remove but fruit, the • peel not Do to have doesn’t that skin soft with fruit • unwashed an Use YOUR OWN PREPARE IS NOTAVAILABLE, JUICE IF UNPASTEURIZED Note: the juice through cheesecloth to remove any flesh. any remove to cheesecloth through juice the Strain cups. 2 to 1 about — class the with use to juice enough get you until blend and blender a in fruit the growth. bacterial inhibits juice orange the of pH low the because experiment this for well work not may juice orange Squeezed peaches. or grapes as such peeled, be Purchase the same type of fruit juice that has been has that juice fruit of type same the Purchase For Each Team of 3 to 4 Students 4 to 3 of Team Each For might students that • equipment the Place 2 to (1 juice • unpasteurized and Pasteurized Class the For MATERIALS • gloves Safety dishes seal to tape • masking or Parafilm • swabs Sterile nutrient with dishes Petri sterile • 4 to 2 FOOD SAFETY CONNECTION FOOD SAFETY not a food has been pasteurized. been has food a not or whether indicate that labels product reading of importance the understand will They safety. food to pasteurization of importance the discover will Students use on a lab table. lab a on use containers clear in each) of cups agar and covers and agar
M O D U L E 3 PROCESSING AND TRANSPORTATION 43 The unpasteurized MYSTERY MYSTERY JUICE Note:
You may need to show the Collect, Organize, and Report Results to food safety. various equipment, and how they designed their experiments, complete with controls. adequacy of the experimental designs. Ask students what they would do to improve their experiments. juice should have a greater number of organisms when samples of both juices are plated on agar plates. Have teams observe the results of their experiment and report their results to the class. experimental designs. Note: students how to dip the sterile cotton swab into the juice and then inoculate the dishes (see page 9).
FOOD SAFETY LAB 3 LAB 2 Conduct the Experiment 3. Ask the students to relate their findings 4. Review how the students used the 1. 2. Together with the students, analyze the 1. Ask the students to review their 2. Have teams carry out their experiments.
organisms growing in it. Some organisms could be dangerous pathogens. all disposable dishes using safe techniques (see page 8). . . Go • Remind students never to open a dish with • After the experiment is completed, discard How do we make observations? (Through the use of our senses. Mostly, we use sight. But sound, taste [although not in this case], and touch are also ways to make observations.) Can you determine which juice is safe to drink just by looking? Today, we’re going to do some detective work, and plan and carry out an investigation. Then you’ll report your findings to the class. It will be challenging! Let’s get started . . . determine great after working after the lab. t before and before and Which juice is safe to drink design an experiment to provide FIRST I have a mystery for you to solve. for for it! and why? mystery by asking: class. List them on the board. the juice. You may wish to help them understand the difference between observation and inference before they start. (Students may notice color and clarity differences. One juice may have some solids in it, etc.) which juice is safer to drink (pasteurized), that’s that’s which juice is safer to drink (pasteurized), evidence for which juice is safe to drink. You may want to review pasteurization with the students. Students can use materials and equipment on the lab table. If your students come up with a variety of ways to to ways of a variety with up come students your If Challenge students to develop their experimental designs designs experimental their develop to students Challenge of a standard case, this (in a control with complete comparison). Ask the students what the different observations may mean. may observations different the what students the Ask to team each challenge observations, class on the Based and is pasteurized juice of which a hypothesis up with come why. explain them have and is unpasteurized one which in the lab (see page 9). masking tape (see page 9). Do you see any differences between them? Remember, all science begins with awareness. What’s one way we become aware? (By making observations) • Seal inoculated Petri dishes using Parafilm or • Disinfect all lab surfaces • Wear safety gloves. • NEVER DRINK ANY JUICE USED IN THE LAB. • Wash hands thoroughly
INTRODUCTION PROCEDURE Together, Together, we’re going to do some sleuthing! Here are two containers of juice. • class: Set the stage for the activity by saying to the LAB 1 Design the Experimen 9. 8. 7. Ask each team to 6. Now ask the students to solve the second part of the 4. 5. 3. Ask each team to share their best observations with the 1. Assign students to work in teams of 3 or 4. 2. Ask each team to record at least 5 observations about Observe Develop a Hypothesis Solve The Mystery SAFETY 3 MYSTERY JUICE
INSTANT REPLAY Time to review and summarize.
1. Which juice would you prefer to drink, pasteurized or unpasteurized? Why? 2. What effect would freezing have on microorganisms in unpasteurized juice? (Freezing does not kill bacteria. It only slows their growth.) 3. How does pasteurization relate to your everyday life? (It keeps our food safe.) 4. Can you tell if a food is pasteurized by looking at it? (No — you should read the product labels.) M O D U L E
SUMMARY RESOURCES
PROCESSING AND TRANSPORTATION Pasteurization is the process of destroying • Food Safety A to Z Reference Guide microorganisms that can cause disease. This is (See the following terms — Bacteria, usually done by applying heat to a food. In order Foodborne Illness, Pasteurization, Pathogen, to determine which mystery juice is pasteurized, and Sanitizer.) both must be plated on agar plates and observed. The unpasteurized juice should have a greater • Dr. X and the Quest for Food Safety number of organisms because it was freshly video/DVD Module 3 – Processing and squeezed and may be contaminated from Transportation handling, etc. It hasn’t been heated to destroy • Web sites bacteria. Pasteurization — Dairy Science and Technology EXTENSIONS www.foodsci.uoguelph.ca/dairyedu/ • Answer the question raised in the video by pasteurization.html Dr. Sizer, “How can you pasteurize an egg in Critical Controls for Juice Safety/FDA the shell without cooking it?” www.cfsan.fda.gov/~dms/fdjuice.html • Research why some milk can be stored on the shelf and some milk must be refrigerated. Keyword: Pasteurization Go to: www.scilinks.org • Write a letter to Louis Pasteur to thank him for Code: FS302 developing the process of pasteurization, and tell him how important this process is in lowering the incidence of foodborne illness. CONNECTION Also, explain how it makes foods more ER E convenient for us today. R See real-life scientists in action! A
• Research how people safely stored food prior to C • www.foodsafety.gov/~fsg/teach.html pasteurization, and choose which method you • Food Safety A to Z Reference Guide think was best — give reasons, specific details, anecdotes, and examples. • Research the history of pasteurization. . . • Relate your pathogen to this experiment and . XT Besides record the information in your food safety E N pasteurization, portfolio. P what other process U destroys harmful bacteria in foods? (Clue: It has to do with the pressure created by 2, 5-ton elephants balanced on a dime.) You’ll discover and explore this process in the next activity.
44 FOOD SAFETY MODULE 3 PROCESSING AND TRANSPORTATION 45
(The (The treatment.) pressure treatment.) to the size of compressed a BB.) size to the FOOD SAFETY What are the positive and negative negative and positive the are What page 47. ADVANCED PREPARATION • Review the Background information on Students will discover the relationship between the 4 Cs of Food Safety and food preservation methods. This finding will reinforce their understanding of why the 4 Cs are important in keeping food safe. FOOD SAFETY FOOD SAFETY CONNECTION are some other issues scientists have to think about when they’re developing methods to preserve food? (Scientists are continually searching for new methods to kill harmful bacteria in food without damaging the look, taste, texture, or nutritional value of food.) affect may method each how discuss and ways of etc. color, value, nutritional taste, texture, the food. the method? each of aspects In addition to destroying bacteria, what different in preserved foods of a variety Show
• •
, /DVD Module 3 — Processing and Transportation (High pressure can kill bacteria without affecting the nutrition, color, or color, nutrition, the affecting without bacteria kill can pressure (High How do you suppose do suppose How you (Orange juice contains water that protects it from being crushed by the ultra ultra by the crushed being it from protects that water contains juice (Orange grandparents Module 3 — Processing and Transportation (Time: 7 minutes). (Time: Transportation and 3 — Processing Module
/DVD . A marshmallow contains air and would be would and air contains pressure. A marshmallow Time: One 45-minute class period ULTRA ULTRA HIGH PRESSURE TREATMENT marshmallow? high pasteurization? of food.) texture discussion should lead to pasteurization, irradiation, and ultra high high ultra and irradiation, to pasteurization, lead should discussion Why can you use ultra high pressure treatment with orange juice and not a not and juice orange with treatment pressure high ultra use you can Why What new ways of processing foods did Dr. Sizer talk about in video? the about talk Sizer Dr. did foods of processing ways new What of forms other over treatment pressure high of ultra benefits the are What
• • • Here are some questions to think about while you are watching the video: the watching are you while about to think questions some are Here Show video Show TIME TO TUNE IN . . . (They either kill bacteria or slow down their growth. growth. their down slow or bacteria kill either (They food.) the of texture or taste the change all they Plus, What do all these methods have in common? in have methods these all do What Dr. X and the Quest for Food Safety video Module 3 — Processing and Transportation – Tomatoes: fresh, sun-dried, canned – Fish: salted, fresh, canned – Fruit: fresh, dried, canned – Herbs: fresh, dried Students Students will explore various ways that have been used to preserve food over the ages. They will also learn about techniques used to process food today and hypothesize about other methods scientists might use to safely process food in the future. Finally, students will conduct a simulation of high pressure treatment and discover how it destroys bacteria without crushing the food. ACTIVITY AT A GLANCE ACTIVITY
INTRODUCTION GETTING STARTED • • 2 empty plastic soda bottles (not rigid bottles) • 2 grapes • A variety of foods preserved in different ways, for example: MATERIALS kept their food safe without refrigerators, sophisticated manufacturing processes, or without even having electricity? (Students may suggest salting, drying, canning, chilling, or freezing, etc. Ice houses kept foods chilled year round, and foods could freeze outside during the winter. List students’ responses.) • Start a discussion by asking: by asking: a discussion Start your great, great, great great great, great, your 3 ULTRA HIGH PRESSURE TREATMENT
INSTANT REPLAY Time to review and summarize.
1. What new ways of processing foods did Dr. Sizer talk about in the video? (The discussion should lead to pasteurization, irradiation, and ultra high pressure treatment.) 2. What are the benefits of ultra high pressure treatment over other forms of pasteurization? (High pressure can kill bacteria without affecting the nutrition, color, or texture of food.) 3. Why can you use ultra high pressure treatment with orange juice and not a
M O D U L E marshmallow? (Orange juice contains water that protects it from being crushed by the ultra high pressure. A marshmallow contains air and would be compressed to the size of a BB.) PROCESSING AND TRANSPORTATION PROCEDURE Let’s see how ultra high pressure treatment SUMMARY works: Throughout the ages, people have found ways to 1. Ask two students to fill the 2 plastic bottles preserve food. Scientists are continually developing completely to the top with water, put a grape new, improved methods of preserving foods. In in each bottle, and tightly close the caps. The addition to pasteurization and irradiation, bacteria water bottle represents the ultra high pressure are now also killed by a new process called ultra equipment and the grape is the food being high pressure treatment. pressurized. 2. Who thinks they can crush the grape Ask: EXTENSIONS by squeezing the bottle? Have students try to crush the grape. Why can’t you crush • Research and write about food preservation the grape? (Water in foods protects the methods in different periods of time. food structure from physical damage during • Hypothesize about other ways you can think of compression. As long as the food is mostly that science might help us preserve foods in the air-free and contains water, pressure doesn’t future. How would you design an experiment to “crush” the food.) test your hypothesis? Indicate which foods you’d 3. Why is pressure being applied to the use your “process” for. food? (Pressure is applied to kill the bacteria.) • Relate your pathogen to this experiment and record 4. How are bacteria killed by the high the information in your food safety portfolio. pressure? (Bacteria are living organisms and the pressure affects their cellular functions. RESOURCES When high pressure is applied to all sides, the • Food Safety A to Z Reference Guide (See enzymes are inactivated.) the following terms — Bacteria, Canning, Freezing, Irradiation, Pasteurization, Pathogen, Preservation, Ultra High Pressure Treatment.) CONNECTION Also see the 4 Cs section on ER E pages 54–63. R See real-life scientists in action! A
C • www.foodsafety.gov/~fsg/teach.html • Dr. X and the Quest for Food Safety • Food Safety A to Z Reference Guide video/DVD Module 3 — Processing and Transportation . . T . EX N You think P
U this activity had pressure? Well, wait until you learn what it takes to manage a supermarket! 46 FOOD SAFETY 3 M O D U L E PROCESSING AND TRANSPORTATION 47
being
and and would die. FOOD SAFETY
The fish the could not withstand psi. pressure where where the is water pressure about 18,000 transported 7 miles down transported into the ocean, The pressure created by 2, 5-ton elephants balanced on a dime is roughly equal to 60,000 psi (pounds per square inch).
(see procedure on that (see page procedure 46) illustrates water in the from foods food protects structure As long compression. during damage physical as the food is and contains air-free mostly does not processing ultra high water, pressure the “crush” food. Foods such as deli meats, salsa, salad, potato and can fruit pieces, be to exposed high to and increase pressure spoilage reduce to change food without safety their structure. can by be bacteria living However, destroyed the of effects on high pressure their cellular functions. be or by damaged affected heat. It’s currently being used salad dressings, to juices, preserve guacamole, oysters, soups, fruit jams, salsas, for and other foods Its is yogurt. application being researched. currently in and flavor food nutrition not are typically can Thus, by high pressure changed pressure. the nutrition, affecting without kill bacteria or color, of texture food.
(protein function, enzyme action, and cellular and action, enzyme cellular function, (protein cells, of bacterial living function) membrane to the thus causing bacteria die. to in living suddenly waters shallow – – You this could to compare a fish accustomed ULTRA HIGH PRESSURE ULTRA TREATMENT The of example the grape in the water bottle for useful UHP foods that is might particularly for that are responsible Small macromolecules can High the impact pressure life processes • • • • BACKGROUND Listeria Listeria O157:H7 and O157:H7 E. E. coli , , in foods. Use this information to help guide students through this activity and to help them understand the new technology of ultra high pressure treatment. monocytogenes Ultra high pressure treatment (UHP) works treatment Ultra high pressure by foods to from 50,000 exposing pressure per pounds inch square (psi) to psi 100,000 for a short time (30 to more seconds than slightly 2 minutes). of of foods have been known for over 100 years. have and only engineers scientists However, necessary the equipment developed recently the high generate and to reliably efficiently to The required kill most bacteria. pressure use recent is of to treatment ultra high pressure and harmful kill microorganisms both spoilage such as pathogens, Preservation methods, such as salting, smoking, such as smoking, methods, salting, Preservation have and been freezing, canning, drying, used over the years to food. As preserve our have skills and engineering knowledge scientific methods. so have advanced, food-preservation All food by the preserve early methods affecting one or more of for needed the bacterial variables pH, and moisture, such as growth, temperature, Many methods of nutrients. the preservation to have a the 4 relationship Cs of Food Safety. In order for preservation methods to methods In be order for preservation foods need to accepted, look and taste good. need to the texture, Scientists taste, consider value of and the nutritional food after it’s been processed.
of The in benefits using pressure the production Ultra High Pressure Treatment (UHP) Treatment Ultra High Pressure • Preservation Methods Preservation • • • 4 RETAIL AND HOME ABOUT THE MODULE Module 4 — Retail and Home — examines the preparation of food in
retail food-service establishments and in the home. Supermarket Smarts — explores all the aspects of safe food handling in a supermarket. The Science of Cooking a Hamburger: Cooking Right — shows the relationship between the temperature to which a hamburger is cooked and the presence of bacteria. A Chilling Investigation — investigates the effect of chilling and not M O D U L E chilling on the growth of bacteria. Crossed Up! — examines how bacteria can be spread among the items in a kitchen if they are not properly cleaned. Hands Off, Bacteria! — analyzes handwashing and its connection to food safety.
SCIENCE CONTENT
This section explains the specific science concepts presented in Module 4 of the video/DVD, including fascinating facts relative to the module. Read this section before watching the video module or conducting the activities and experiments.
RETAIL
The 4 Cs Connection — In any restaurant or place that serves food, the 4 Cs are critical. Sometimes, the 4 Cs can be taken care of by technology.
Hi-Tech Hamburgers — Fast-Food Technology To eliminate human error, an engineer developed a 2-sided “clam shell” type grill that has a temperature sensor. It cooks burgers on both sides simultaneously, using a sensor to assure that all of the burgers reach a safe internal temperature.
Important Note: The “clam shell grill” is only one way to ensure safer food. Other methods, such as cooking on a grill and flipping burgers, are also effective. The point is to assure that foods are cooked to a high enough temperature to kill any Two-sided grill pathogens.
Handwashing
Humans are one of the biggest sources of food contamination in restaurants. So, handwashing is critical to keep food safe. For example, contamination can occur when someone doesn’t wash their hands and then prepares or serves food.
FASCINATING S T C A F
50 billion meals a year are eaten outside the home.
48 FOOD SAFETY 4 M O D U L E RETAIL AND HOME 49 SCIENCE CONTENT SCIENCE FOOD SAFETY
— Cook foods to proper temperatures. Using a Using temperatures. to proper foods — Cook — Refrigerate promptly. Refrigerate or freeze foods foods or freeze Refrigerate promptly. — Refrigerate Combat Cross-Contamination — Keep raw meats, poultry, and seafood — and the juices from raw foods — away from other foods in your shopping cart, on kitchen counters, and in your refrigerator. food thermometer is the only reliable way to ensure that that to ensure way reliable only is the thermometer food internal a safe reach poultry and meat, hamburgers, temperature. k Cook hands. with hands Wash often. Clean surfaces and — hands Wash utensils, dishes, boards, cutting and water, soapy warm, food after and before water soapy hot, with surfaces and preparation. Receiving Receiving areas are maintained at cold temperatures of 41° F (5° C) or below to maintain the cold chain that started way back in the field. and clean kept are cases display and areas Storage controlled. temperature Food preparation areas are also kept clean, and are set up to avoid cross-contamination. Foods are always separated to avoid cross-contamination. Red meats, fish, and poultry will never be mixed together or mixed with fruits and vegetables. Even with all the great technology, food can still become contaminated, so it’s important for YOU to always practice the 4 Cs of Food Safety. Once you purchase food and take it home, the responsibility for food safety is literally in your quickly because cold temperatures keep harmful bacteria bacteria harmful keep temperatures cold because quickly or Refrigerate Rule: 2-Hour The multiplying. and growing from within leftovers and foods, prepared perishables, freeze or less. 2 hours Chill HOME Overview of 4 Cs in the Home Supermarkets The Barkley family practicing the 4 Cs of Food Safety. The milk is stored in clean, temperature-controlled display cases. M O D U L E 4 50 RETAIL AND HOME • • prepare to students for materials Assorted • MATERIALS GETTING STARTED supermarket and in restaurants. restaurants. in and supermarket the at safety food about say Tracy and X Dr. what out find let’s begin, we before But supermarket. a in departments specific managing of role the on take to going we’re Today you! for challenge a have I INTRODUCTION on page 54 of the High School Teacher’s Guide.) Teacher’s School High the of 54 page on the See supermarket. a for substituted be could restaurant food fast- (A presentation. innovative an in findings its present will team each activity, this of end the At Safety. Food of Cs 4 the using department that designing through department food specific a of needs food-safety the researching from department, supermarket food-safe own their manage and establishments. food retail in safety food of importance the of awareness an develop will students activity, this In ACTIVITY AT AGLANCE
class presentations class Module 4 — Retail and Home and Retail — 4 Module video/DVD, Safety Food for Quest the and X Dr. bag Grocery Y T E F A S D O O F one for the presentations the for one and activity the to introduction an for one — periods class 45-minute Time:Two SUPERMARKET SMARTS
They will be challenged to design to challenged be will They
activity Footwork Food Fast ADVANCE PREPARATION • •
– – – – – the bag on your desk. your on bag the place and bag, grocery a in papers the Place offeragood variety of food-safety principles.) onaseparate piece of paper. (These departments Writethe names of each supermarket department consumers and employees. and consumers better them make help will restaurant) food fast- (or supermarket a in handling food safe of aspects the all Exploring establishments. retail from food purchase Students FOOD SAFETY CONNECTION FOOD SAFETY Checkout/Employee break area break Checkout/Employee Dairy/Eggs Produce Deli Meat/Poultry/Seafood
M O D U L E 4 RETAIL AND HOME 51 SUPERMARKET SMARTS SUPERMARKET FOOD SAFETY (The cold chain is a series of actions (Handwashing is critical to keeping food safe.
— Food-preparation areas must be kept clean to avoid Module 4 — Retail and Home Foods need to be chilled or frozen to stay fresh.) Time Time to review and summarize. — Employees in restaurants and food stores must clean their hands. Storage — Temperature probes should be used to make sure that food is cooked to the X discussed the “cold chain.” What is it?
Clean Contamination can occur when someone doesn’t wash his/her hands and then prepares or serves food. Employees must follow strict handwashing guidelines, and customers should wash their hands before they eat the food.) ( cross-contamination. There are separate departments for raw meat, fish, poultry, and produce to avoid cross-contamination. right temperature. areas and display cases must be kept clean. is literally in your hands”? by that? that maintain the temperature of food as it travels from the farm to the table.) How does the cold chain come into play in the supermarket? (Supermarkets are a link in the cold chain. Storage areas and display cases are kept at a safe temperature to keep food frozen or chilled.) Dr. What does Dr. X mean when he says, “The responsibility for food safety Dr. X told us that supermarkets are “major 4 C territory.” What did he mean
How do supermarkets practice the 4 Cs? How are supermarkets a link in the cold chain? What does Dr. X mean when he says, “The responsibility for food safety is literally in your hands”?
3. 2. 1. Cross-Contamination Cook Chill — • • • PART 1 — RETAIL Here are some questions to think about while you’re watching the video: Show video/DVD Module 4, Part 1 — Retail (Time: 3 minutes). TIME TUNE TO IN . . . INSTANT REPLAY INSTANT M O D U L E 4 52 RETAIL AND HOME SUPERMARKET SMARTS 3. 2. 1. INSTANTREPLAY PROCEDURE Y T E F A S D O O F
their plan. Students can consider the following the consider theircan plan.Students presentto presentation innovative an prepare and safe, is department their in food the that food-safetyprogram foryourdepartment. Workwithyour teammates createto a foodbornepathogens growtospread.or challengereducetois the opportunity for yoursupermarket department. Your teams: departmentfromthe grocery bag.Tell the Havemembera fromeach team select a teams. 5 into class the Divide Have each team develop a plan a develop team each Have actions: • • personnel must follow. must personnel store the procedures what out find to regulations federal and state, local, Research manager. store a interviewing and/or Internet the using by department the of needs food-safety the Research Today,you’ll themanagerbe of 1. 4. 3. 2.
Whose responsibility is it to keep food safe once the food is purchased? is food the once safe food keep to it is responsibility Whose hands.) his/her (Wash illness? foodborne prevent to do can employee an things important most the of one What’s safety? food supermarket with do to has science think you do What know? didn’t you that safety food supermarket about discovered you things some are What (The customers) (The Time to review and summarize. and review to Time
for assuring for 6. 5. 4.
4 Cs of Food Safety. Food of Cs 4 found in each of the five departments. Ask departments. five the of each in found needs food-safety the compare class the Have idea. original an with up come Or model. 3-D or play, song, poem, advertisement, poster, page, Web presentation, Point Power a Make department. the into incorporated was safety food how show and class, the to design department the Present differences? students: Design • • • the employees. the Include handwashing Include department? the in play into come chain cold the does How department. the in play Safety Food of Cs 4 the that role the Analyze
the department so that it follows the follows it that so department the What are the similarities and similarities the are What
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4 M O D U L E RETAIL AND HOME 53
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FOOD SAFETY /DVD Food Marketing Institute (FMI) www.fmi.org How to Size Up a Restaurant/Kansas Department of Health and Environment Food Protection and Consumer Health http://www.kdheks.gov/fpcs/how_to_size.html International Food Safety Council/National Restaurant Association (NRA) www.restaurant.org www.cfsan.fda.gov/~dms/foodcode.html educators/ccp.cfm?articleID=62&parent=2 Food Code/Food and Drug Administration The Consumer Control Point Kitchen/Iowa State University http://www.extension.iastate.edu/foodsafety/ Dr. X and the Quest for Food Safety video Food Safety A to Z Reference Guide (See the following terms — Used By” Date, Cold Chain, Contamination, Expiration Date, Foodborne Illness, Food Code, Food Inspection, Food Safety, Food Thermometer, Handwashing, Hazard Analysis and Critical Control Point, Pathogen, Perishable, Refrigeration, “Sell By” Date, “Use By” Date, Shelf Stable, and Sanitation.) Also see the 4 Cs section on pages 54–63, and The Safe Food Chart on pages 64–71. Web sites:
RESOURCES • • •
Fast in Module 4. www.foodsafety.gov/~fsg/teach.html
• Food Safety A to Z Reference Guide See real-life scientists in action! • a food-safety training session for employees employees for session training a food-safety
CONNECTION
For more activities related to Retail, see the High School Teacher’s Guide activity, R Food Footwork,
E
E P I T R A your foodborne pathogen relates to your findings in this activity. C learned in this activity to restaurants, picnics, cookouts, banquets, and your own kitchen at speak to your class about the food-safety guidelines they follow. How do those guidelines relate to the 4 Cs of Food Safety? in your area of the supermarket. Make a list of guidelines that each employee must follow. Present to the class. home. out how he or she assures food-safety. it kept safe until you purchase it? How many times is it touched and by whom? Is there a way to ensure that all those who touch the food have clean hands? Report your findings. happens to the food between the time you take it out of the supermarket and get it home. Build in at least three 4 C violations. You can also try to identify the violations and then propose a plan for minimizing the risk. Use your food-safety portfolio to record how Do a follow-up lesson applying what you’ve Ask your school’s food-service manager to Trace a food through the supermarket. How is Create an FBI Case scenario about what Interview a local supermarket manager and find Plan
Other Food-Service Establishments • • • • • • • EXTENSIONS Supermarkets Food safety is an important aspect of designing and managing a supermarket. There are strict regulations governing food service, and the regulations are science-based. Everyone has responsibility for food safety — managers, employees, and customers. SUMMARY Food-Safety Portfolio M O D U L E 4 54 RETAIL AND HOME • • • • • • • • • • • • • • • • • • • Disinfecting and Cleaning For MATERIALS For Safety For Dishes Petri Swabbing For Hamburger Cooking and Preparing For GETTING STARTED
students are familiar with and may be cooking at home. at cooking be may and with familiar are students that food a it’s because experiment cooking this for used is Hamburger bacteria. pathogenic kill will C) (71° F 160° of temperature recommended the to hamburgers cooking that learn also will They temperature. each at bacteria of amount the observe and hamburger with inoculated dishes Petri analyze will Students temperatures. different to hamburgers cooking demonstrate will teacher The LAB ATAGLANCE Y T E F A S D O O F Thermalgloves orhot pads for handling the hot sterile5 Petri dishes with nutrient agar and covers Safety gloves, safety glasses, lab aprons for aprons lab glasses, safety gloves, Safety marker Permanent swabs cotton Sterile, dishes seal to tape masking or Parafilm hamburgers cooked for plates paper Clean skillet from hamburgers removing for Spatula knife Sharp thermometer food instant-read digital, 1 from hamburgers the keep to spray Non-stick skillet regular a and plate Hot hamburgers the weighing for Scale ruler Metric raw inexpensive, of grams) (227 pound .5 towels Paper isopropyl and balls cotton or wipes Alcohol liquid of ml (20 solution bleach Disinfecting detergent Dishwashing anyone handling and/or cooking meat cooking and/or handling anyone best) is type thin-probe (rapid-read, cooking during pan the to sticking hamburgers) pre-molded use not do — each grams 50 approximately patties, (4 chuck as such hamburger, 9) page see water, tap of L 1 in bleach household alcohol skillet beginning of the next class period. class next the of beginning Time: Right Cooking HAMBURGER: A COOKING OF SCIENCE THE
One 45-minute class period to conduct the experiment. Observe results at the at results Observe experiment. the conduct to period class 45-minute One • Review • ADVANCE PREPARATION • • • • •
Right Photocopy TIPS classroom.studentstheenterascook grams) to hamburgerPrepare(approximatelypatty1 50 55. page on Background Review thermometer. food a of use proper the with yourself Familiarize agar. nutrient containing dishes Petri sterile 5 Prepare to prepare for class demonstration. class for prepare to Guide, pages 60–63.) pages Guide, Teacher’s School High the (See experiment. the conduct students have can you lab, the in meat raw cook and handle to students allows school your and prefer, you If demonstration. teacher a as designed is experiment This Note: Purchase hamburger. Purchase • refrigerator the of out hamburger the Take •
speed up the cooking process. cooking the up speed will This bit. a up it warm to enough long just class, before hour half a about insideusing hota plate. experimentoutside ongrilla instead of Inwarmer weather you might conduct for each student on page 59 (optional). 59 page on student each for CONNECTION FOOD SAFETY important to prevent foodborne illness. foodborne prevent to important is temperature internal safe a to them cook to how Knowing teenagers. many of diet the in staple a are Hamburgers Demonstration Lab Sheet: Cooking Right Cooking Sheet: Lab Demonstration Lab Sheet: Cooking Sheet: Lab Demonstration this
M O D U L E 4 RETAIL AND HOME 55
E. FACTS
Research done by the U.S. U.S. by the done Research of Agriculture Department 4 1 of every out that shows in brown turns hamburgers it is safely before middle the beef ground Some cooked. at internal done look patties as as low temperatures C). F (57° 135° the half than Less a food owns population only And thermometer. a thermometer use 3% like foods cooking when home. at hamburgers
• • FASCINATING FOOD SAFETY E. coli O157:H7 can be in our hamburger, coli O157:H7, can find its way into some foods, like hamburger. Because there’s a possibility that it’s important to cook all ground meat to a safe internal temperature. from the supermarket is safe, however there is a remote possibility that bad bacteria, such as bacteria present in raw hamburger and in hamburgers cooked to different temperatures. Let’s see what happens! Explain to the students that most hamburger We’re going to explore the amount of
• • Take a tally
the hamburger patty. patty. hamburger the inside How can you be BACKGROUND Why? Let them discuss THE THE SCIENCE OF COOKING A HAMBURGER: Cooking Right FIRST List the students’ answers. Then explain: Disinfect any surfaces that come in contact with the raw meat (see page 9.) page (see meat raw the with in contact come that surfaces any Disinfect It’s particularly important to thoroughly cook ground meats, meats, ground cook thoroughly to important particularly It’s for chance a greater there’s because hamburger, as such whole with than meat ground with contamination bacterial meat. the of outside the on out start bacteria The cuts. can outside the on bacteria any ground, is meat the When when addition, In hamburger. the throughout distributed be and utensils, hands, from bacteria harmful patties, making transferred be can surfaces It may not always be possible to check the hamburger with a with hamburger the check to possible be always not may It a restaurant. in eating you’re when example, for thermometer, be to hamburger the for ask to is thing safest the case, this In in pink it’s if back it Send F. 160° of a temperature to cooked middle. the An “instant-read” dial food thermometer with a probe in the of hamburgers. temperature proper the checking for is best tip The probe should be inserted in the side of the burger, so the entire sensing area (usually 2 to 3 inches [5 to 8 cm]) is positioned into the center of the burger. It’s important, therefore, to make sure that the internal internal the that sure make to therefore, important, It’s enough a high reached has hamburger the of temperature pathogens. foodborne any kill to C]) F [71° (160° temperature Beware of hot surfaces. Use a thermal hot pad when handling skillets, hot plates, etc. plates, hot skillets, handling when pad hot a thermal Use surfaces. hot of Beware Wear safety gloves, safety glasses, and lab aprons when handling or cooking the meat. the or cooking handling when aprons lab and glasses, safety gloves, safety Wear organisms could be dangerous pathogens. of the class. Now ask, their reasons for about 5 minutes. eat? Today you’re going to use science to help answer that question. What do you think science has to do with cooking a hamburger? Let’s find out! so you won’t get sick,” ask: sure that this hamburger will be safe to — — well done, medium, or rare? If no one has brought up, “it’s safe to eat or How do you want your hamburger cooked cooked hamburger your do want How you
• Properly dispose of all raw meat. • Seal all dishes with Parafilm or masking tape. Never open a Petri dish with organisms in it; some • • Thoroughly wash all thermometers between uses with soap and water, or clean with alcohol pads. • • DO NOT EAT OR TASTE ANY OF THE HAMBURGER used in the experiments. • Your hands and lab surfaces may be contaminated after being in contact with raw meat. – – Thoroughly wash your hands before and after handling the raw meat. • • • • Have a hamburger cooking as students walk into the room. Ask students: • SAFETY INTRODUCTION M O D U L E 4 56 RETAIL AND HOME THE SCIENCE OF COOKING A HAMBURGER: Cooking Right Cooking HAMBURGER: A COOKING OF SCIENCE THE 4. 3. 2. 1. the Use 5. you demonstrate. you as experiment the design and analyze students help to inquiry guided for suggestions following the Use experiment. the conducting for guide a as PROCEDURE LAB 1 LAB Y T E F A S D O O F
Ask students: Ask Showstudents howswabto the rawhamburger, dish. control a up set to how Demonstrate 160°(71°FC), C); see page (60° 9. F 140° C), (49° F 120° raw, control, dishes: Askvolunteers assistto youlabelingin Petri5 seal (see page 9). page (see seal to dish the tape and dish, “raw” the inoculate proceduresforhandling rawmeat (see page 8). studentswearsafety gloves andfollow safety andmeasure thehamburgers. Makesure Option: areallthesame weight andthickness. weigh— andmeasure themassureto thatthey Demonstratehowprepareto hamburgers3 • • •
hamburgers vary in size, another variable is variable another size, in vary hamburgers the (If Why? weighed.) be should (They introduced.) thickness.) this of burger a in thermometer the insert accurately to easier It’s thick. cm] [1.3 inches .5 about be should (Burgers matter? hamburgers are the same size? same the are hamburgers the all that assure we can How experiment? this conduct we as considered be should factors What Does thickness of the hamburgers the of thickness Does temperature, consistency, etc.) consistency, temperature, hamburgers, of thickness size, (Weight,
Demonstration Lab Sheet: Cooking Right Cooking Sheet: Lab Demonstration Teacher Demonstration with Guided Inquiry Guided Teacherwith Demonstration Havestudent volunteers make, weigh,
6. 10. 9. 8. 7.
Cook one hamburger to 120° F 120° to hamburger one Cook
it rather than cut it in this scientific this in it cut than rather it Ask: inside. the swab to (49°C), Whenthe hamburger has reached 120° F incubator at incubator the in dishes Petri inoculated the Place hamburger.) the into bacteria that transfer might you and it on bacteria have might knife (The test? to seal.to reachedthedesired temperature. Tapedishes inoculatethedishes after eachhamburger has (60°andC)160°(71° F C), have volunteers Cooktheremaining hamburgers 140°toF seal. to dish the Tape dish. F” “120° the inoculate and hamburger the of edge broken the inside swab volunteer a Have • • •
hamburger you’re cooking.) you’re hamburger next the to transferred be and thermometer the onto get might they meat, the in bacteria are there (If necessary? this is between uses. between water hot and soap with thermometer the wash thoroughly can you home, at cooking you’re when However, experiment. this in cross-contamination prevent and bacteria Note: (cross-contamination) called? time you take the temperature. Ask: temperature. the take you time each alcohol with thermometer the Clean Howshould you take the temperature? hamburger.) the of inside the of reading temperature accurate an getting with interfere will pan the from heat (The temperature? the measure to pan the of out hamburger the take students: Ask thethermometer package.) justthe outer edge. Follow the instructions on probereaches the center ofthe burger, not intothe center, making sure the temperature (Takethe temperature through the side and break it in half and demonstrate how demonstrate and half in it break We’re using alcohol to kill any kill to alcohol using We’re 35° C ( 35°C Why is it important to important it is Why 95° F 95° Why do you break you do Why ) for 1 to 2 days. 2 to 1 for What is this is What (49°C) . Why
4 M O D U L E RETAIL AND HOME 57 Food some probable
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FOOD SAFETY What did your control show? burgers? (The raw hamburger will have much more bacteria than any of the cooked hamburgers.) How did the amount of bacteria in the raw hamburger compare to the cooked
• • Seafood? Eggs? (The general learnings about cooking apply
THE THE SCIENCE OF COOKING A HAMBURGER: Cooking Right A to Z Reference Guide (pages 54–63) and the Safe Food Chart (pages 64–71). Time Time to review and summarize. y (List students’ responses.)
safe to eat. other foods on them. Safet Does what we learned about hamburger apply to other foods as well? What about poultry? Fish? What are some things we’ve learned in this lab? student responses, but probe for more: to raw poultry, fish, seafood, and eggs.) For proper cooking temperatures and other information about poultry, fish, seafood, and eggs, see the 4 Cs section of the What are some ways our food can become contaminated after we purchase it?
(The temperature of 160° F [71° F [71° 160° of temperature (The 3. 2. 1. – Cooking a hamburger to 160° F (71° C) is the only way to tell that a hamburger is – Temperature should be taken in the center of the hamburger from the side. – Surfaces used to prepare raw meat must be thoroughly cleaned before preparing Observe, Observe, Record, and Report C] should show the best results. This is the the is This results. best the show should C] cooking safely for temperature recommended meat.) ground Which temperature produced the most most the produced temperature Which bacterial reducing in results effective numbers?
INSTANT REPLAY INSTANT LAB 2 LAB 2 At the beginning of the next day’s lab, have students observe, record, and report bacterial numbers in the 4 samples. Ask students to • discuss: M O D U L E 4 58 RETAIL AND HOME THE SCIENCE OF COOKING A HAMBURGER: Cooking Right Cooking HAMBURGER: A COOKING OF SCIENCE THE • • • • • EXTENSIONS before cleaned thoroughly be must surfaces and Hands thermometer. food a use to is correctly cooked is meat if determine to way best The temperature. internal safe a to meat cook to important It’s SUMMARY
Y T E F A S D O O F Relate your pathogen to this experiment and experiment this to pathogen your Relate food a using on campaign food-safety a Prepare interview and restaurant fast-food local a Visit food- of importance the on brochure a Write farm the from hamburger a of path the Trace record the information in your food-safety your in information the record organization. parent other or PTO local your for meat cooking when thermometer internal safe a to cooked are hamburgers the sure makes he/she how out find to manager the etc. fundraisers, events, school events, sports at cooking groups and administrators school the to distributed be to precautions safety report. your in Safety Food of Cs 4 the of each Include it. eat you when safe is burger the that ensure to do must you what and begins responsibility your where indicating by continuum the Complete you? reaches it from free is hamburger the that assure help to do continuum the along everyone does What table. the to CAR portfolio. temperature. EE R N O I T C E N N O C and after Food Safety A to Z Reference Guide Reference Z to A Safety Food • • action! in scientists real-life See
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American Meat Institute (AMI) Institute Meat American • • • RESOURCES
The Consumer Control Point Kitchen/Iowa State Kitchen/Iowa Point Control Consumer The to Relates It as Beef Ground Cooked of Color DVD Module 4 – Retail and Home. and Retail – 4 Module DVD The Thermy™ Campaign/USDA Thermy™ The http://www.extension.iastate.edu/foodsafety/ University State Kitchen/Iowa Safe a to Steps Ten Education Safety Food for Partnership The Association Beef Cattlemen’s National http://www.kidshealth.org/parent/ Health Family/Kids Your for Safety Food (NRA) Association Restaurant National Council/ Safety Food International Health Cooks/Kids Teen for Safety Food www.foodsafety.gov Information Safety Food Government to Gateway 63) and the Safe Food Chart (pages 64–71). (pages Chart Food Safe the and 63) 54– (pages section Cs 4 Pathogen.)the see Also FoodSafety,to Steps Germ, Handwashing, and Four Thermometer, Food Safety, Food Illness, Foodborne Zone, Danger Contamination, Cross- Bacteria, — terms following the (See color_of_cooked_ground_beef/index.asp http://www.fsis.usda.gov/Fact_Sheets/ Doneness/FSIS www.meatami.org www.fsis.usda.gov/thermy parent=2 educators/tensteps.cfm?articleID=48& www.fightbac.org www.beef.org firstaid_safe/index.html www.restaurant.org nutrition/food_safety.html http://kidshealth.org/teen/food_fitness/ educators/ccp.cfm?articleID=62&parent=2 http://www.extension.iastate.edu/foodsafety/ University Web sites: Web video/ Safety Food for Quest the and X Dr. Guide Reference Z to A Safety Food FS303 Code: www.scilinks.org to: Go E-coli Keyword:
DEMONSTRATION LAB SHEET
COOKING RIGHT GETTING READY • Wash your hands with hot, soapy water. • Carefully remove the wrap from the hamburger by slitting the wrap along 3 • Use one alcohol wipe to sanitize the outside sides of the package, being careful not to wrap of the hamburger, and one alcohol wipe to touch the meat with the knife. Then peel sanitize the knife. the wrap away from the meat. This helps ensure that you haven’t cross-contaminated the hamburger with the knife or the wrap. This is important for a scientific experiment, but not necessary at home. CONDUCT THE EXPERIMENT 1. Prepare a control plate. • Take the temperature by inserting the 2. Remove a small section of the raw hamburger thermometer through the side into the and swab inside the hamburger to get the center of the burger. juices. Inoculate the “raw” plate. Discard the – One person should use a spatula to raw hamburger section. steady the hamburger on one side 3. Divide the remaining hamburger into thirds. while another person quickly takes Weigh them to ensure equal weight (50 grams the temperature. Remember that the is a good size for testing). Make 3 patties each hamburger is hot! .5 inch (1.3 cm) thick. – If the temperature hasn’t reached 4. Spray the skillet with non-stick spray to keep 120° F (49° C), return the burger burgers from sticking. to the skillet and continue to cook. 5. Cook one hamburger to 120° F (49° C). Don’t – If the temperature is higher than 120° F push down with the spatula — it squeezes the (49° C), return the burger to the skillet juices out. and continue to cook to 140° F (60° C). You will then use your third patty to 6. Lift the patty out of the pan with a spatula cook to 120° F (49° C). and place it on a clean paper plate to take the temperature. Temperature should be taken • Clean the thermometer with an alcohol within 15 seconds to get an accurate reading, wipe each time you use it. Remember because the hamburger continues to cook even that bacteria are not killed until the though it’s removed from the heat source. burger reaches the correct temperature. If the burger hasn’t reached the correct temperature, you might reintroduce bacteria into your burger with a contaminated thermometer. 7. Break the patty in half and place on a paper plate. Swab inside the broken edge to get the juices from the burger. Inoculate plate 120° F (49° C). 8. Repeat this procedure, cooking patties to 140° F (60° C) and 160° F (71° C). INCUBATE PETRI DISHES 1. Tape the dishes to seal (see page 9). Observe, record, and graph bacterial 2. Place Petri dishes in an incubator at growth of the samples. 90° F (32° C) or let the dishes sit at room temperature (away from the sun) for the appropriate amount of time.
FOOD SAFETY 59 M O D U L E 4 60 RETAIL AND HOME • • • • • • • • • • • inexpensive, of package grams) (227 pound .5 • MATERIALS left out of the refrigerator for too long. too for refrigerator the of out left unintentionally be might meat when of scenario a with up come to students ask or introduction, an as scenario following the use can You INTRODUCTION GETTING STARTED
Thislab will beconducted asteachera demonstration. properlychilled inorder for itto remain safe toeat. Thelab reinforces the concept that food must be temperatureand hamburgera that’s kept refrigerated. betweenhamburgera that’s left out atroom Studentswill observe the difference inbacterial count LAB AT AGLANCE Y T E F A S D O O F (page 23) (page Outline Report Lab the keep to pack ice with cooler or Refrigerator swabs cotton Sterile sterile3 Petri dishes withnutrient agarand handling anyone for aprons lab and gloves Safety towels Paper packages hamburger for plates 2 bags plastic self-sealing 2 package hamburger cutting for Knife Disinfectingbleach solution (20 mlof liquid and utensils cleaning for detergent Dishwashing hamburger countertops raw hamburger raw meat chilled meat covers householdbleach inofL1 tap water, see page 9) Observe and record the results the next day next the results the record and Observe Time: CHILLING INVESTIGATION A
One 45-minute class period to conduct the experiment the conduct to period class 45-minute One Divide the hamburger package in half by cutting by half in package hamburger the Divide • knife. the Disinfect • hamburger. Purchase • PREPARATION ADVANCE for Outline Report Lab the of photocopy a Make • a in or plates on packages the put to sure Be • • • seal. and bag self-sealing a in half each Put • if there’s any difference between them. between difference any there’s if unrefrigerated hamburger? Why or why or Why hamburger? unrefrigerated students: Ask not? eat. to safe was hamburger unrefrigerated the if wondered but refrigerator, the in hamburger the placed and morning next the up woke She long. night all counter kitchen the on out sat It refrigerator. the in hamburger of package other the put to forgot She her. distracted that occurred things other and rang, phone the then But refrigerator. the in package one put She dinner. for cook to planned she that hamburger of packages 2 bought Smith Mrs. night, Last Scenario: Suggested Label one bag “chilled” and refrigerate immediately.
Labelthe other bag “room temperature” and leave bottom of the Styrofoam™ tray. Styrofoam™ the of bottom the and meat the including package, the through each student. each counter. the onto or refrigerator the in items food other onto leaking from juices meat raw prevent to bowl itout atroom temperature atleast overnight. FOOD SAFETY CONNECTION FOOD SAFETY whendefrosting and cooking. therefore,it’s important toproperly handle meat microbialgrowth. Itdoes not kill microorganisms; Chillingiscriticala method for controlling
Let’s test both hamburgers and see and hamburgers both test Let’s Would you eat the eat you Would
A CHILLING INVESTIGATION 4 PROCEDURE E L U D HOME RETAILAND O M
LAB 1 Conduct the Experiment
1. Have the class form a hypothesis about the • Have the third student label one dish “room properly refrigerated hamburger versus the temperature.” Swab the hamburger that hamburger left out at room temperature. was left out of the refrigerator, and inoculate 2. Now ask: How would you test your the “room temperature” dish. hypothesis? Record their answers. 5. Tell the students that one package of 3. Discuss a good experimental design for this lab. hamburger was cut in half to make two packages. Then ask: 4. Ask for three volunteers. • Why did we cut the package in half • Remind them to wear safety gloves. They rather than just buying 2 individual should take their sample near the center of packages? (To ensure that the meat the meat and away from the surface where tested is from the same batch, so as not the hamburger was cut. If possible, get a to introduce another variable into the drop of hamburger juice. experiment) • Have one student label one Petri dish “control.” 6. Tape the dishes to seal them (see page 9). • Have the second student label one dish 7. Place the Petri dishes in the incubator at “chilled.” Have them swab the properly chilled (35° C) for 1 to 2 days. hamburger, and inoculate the “chilled” dish.
LAB 2 Observe, Record, and Summarize Results
This will be done at the beginning of the next day. 4 Cs of Food Safety — she violated the 1. Have the class discuss the results in relation to 2-hour rule by not placing the hamburger in their hypothesis. Were there any surprises? the refrigerator immediately. 2. Ask students: Did the cold kill the bacteria in • Who has the final responsibility for the the refrigerated sample? (There may be some safety of this burger? (It’s our responsibility to bacterial growth, since cold doesn’t kill bacteria.) make sure that food stays safe after we purchase it.) 3. What did you observe in the unrefrigerated 5. Could I just cook the unrefrigerated sample? (Since the sample had remained in the hamburger thoroughly and make it safe “Danger Zone” for several hours, more bacteria to eat? (No. If food is left unrefrigerated, bacteria grew than on the refrigerated sample.) cells will grow and more heat is required to kill the additional cells. Also, leaving the meat 4. What can you conclude about what went unrefrigerated invites the possibility of cross- wrong along the Farm-to-Table Continuum contaminating surfaces, hands, etc. You should in respect to this hamburger? practice safe food-handling habits and always • The burger may have been contaminated handle your food defensively. If the hamburger was with bacteria before Ms. Smith purchased it. left out at room temperature for more than However, she compounded the problem by 2 hours, it should have been discarded.) mishandling the meat after she brought it Students can use the Lab Report Outline home. She did not follow the “Chill” rule of the (page 23) to record the results. INSTANT REPLAY Time to review and summarize.
1. What does the cold chain have to do with the things we learned in this lab? (We all need to continue the cold chain that started back on the farm in order to keep our food safe. Keep food chilled until it’s ready to be cooked or eaten.) 2. Why do we freeze hamburger meat? (Freezing keeps food safe by causing foodborne illness microbes to enter a dormant stage.) 3. Does freezing kill bacteria? (No, freezing slows down the growth of harmful bacteria.)
FOOD SAFETY 61 M O D U L E 4 62 RETAIL AND HOME A CHILLING INVESTIGATIONA C • • • EXTENSIONS freezer. or refrigerator the in away right used be won’t that foods store always multiplying, and growing from bacteria harmful keep to . . . simple is answer the Well, question! the is that freeze, to not or freeze To SUMMARY
A Y T E F A S D O O F R record the information in your food safety food your in information the record etc. eggs, seafood, fish, chicken, as such foods other to chilling and growth portfolio. she maintains the cold chain. cold the maintains she he/ how out find to manager the interview and Visit a local fast-food restaurant or supermarket or restaurant fast-food local a Visit EE and experiment this to pathogen your Relate bacterial about learned you’ve what Relate R N O I T C E N N O C Food Safety A to Z Reference Guide Reference Z to A Safety Food • • action! in scientists real-life See
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M O D U L E 4 RETAIL AND HOME 63
Sponges, dishcloths, dish towels, can openers, refrigerator and faucet handles, countertops, and cutting boards are among the items in a kitchen that can spread bacteria if they are not cleaned properly. FOOD SAFETY FOOD SAFETY CONNECTION
FOOD SAFETY This experiment should be set up to avoid Students should include items they think will have lots of bacteria as well as those they think will have fewer bacteria. For example, they may want to compare new sponges or just-washed dishcloths with dirty or just-used sponges or dishcloths. Items don’t have to be taken from the class list. Teams can pick their own items to investigate. Try for as many different items as possible but make sure the important ones, such as sponges, dish cloths and dish towels, are included by at least 2 teams. – – Bring in 1-gallon, sealable plastic bags for each Group students into teams of 3 to 4. Ask each Give each team 1-gallon storage bags to take student. team to choose at least 3 or 4 kitchen items they want to inspect. home. Ask them to bring in kitchen items from home to test. Students should ask their parents’ permission to bring the items to class. Ask them to put in 1 item per bag, seal the bag, and bring it to class.
• Note: any comparing and critiquing of items from students’ homes. Put a number on each bag as students give them to you. Write each student’s name on a list with their corresponding bag number. The experiment should be a general learning experience about how to avoid cross- contamination in the kitchen, not a specific review of individual items. For example, students should look for common items that are most likely to harbor bacteria. • •
Why . Utensils Cutting boards Dishes Sink stoppers or disposal covers Paper towels – – – – – most bacteria and Bacteria are everywhere, Three 45-minute class periods least bacteria. Make 2 lists:
Time: Time: CROSSED UP! CROSSED Introduce the Experiment Can-opener blades Sponges Dish towels Pot scrubbers Vegetable brushes Dish cloths You may want to send home a note to explain the reason you’re asking students to bring in items from their kitchens. – – – – – – Then ask students to vote on the items most most items the on vote to students ask Then Now, ask students to hypothesize about which Could bacteria be on items that you or Where in your kitchen could bacteria be Make a list of students’ responses. would/wouldn’t bacteria be found on these items? growing? which contain the “Most Bac” and “Least Bac.” Ask them: and least likely to harbor bacteria. List the Top 5 Top the List bacteria. harbor to likely least and the on 5 lists Top the Keep category. each in items can students so labs few next the through board lists. the with results lab their compare kitchen items contain the your parents use when preparing food? Some Probable Answers: Students will discover that some items in their kitchens kitchens their in items some that discover will Students to challenged be will They bacteria. by contaminated be may kitchens in found be might bacteria where about hypothesize bacteria. least the and most the have might items which and spread can bacteria that awareness an develop will Students hypothesize will and food, to even and hands, to surfaces from bacteria. of spread the control to how LAB AT A GLANCE LAB AT A
LAB 1 LAB 1
INTRODUCTION • ADVANCE PREPARATION • •
• • including in your very own kitchen! In this lab, you’re going to become kitchen inspectors and look in your kitchens for things that may contain bacteria Explain to students: Ask students: M O D U L E 4 64 RETAIL AND HOME CROSSED UP! LAB 2 LAB • PREPARATION ADVANCE • • • • • • Class the For MATERIALS • For Each Team of 3 to 4 Students 4 to 3 of Team Each For GETTING STARTED 3. 2. 1. PROCEDURE
Y T E F A S D O O F weren’t able to bring items. items. bring to able weren’t 2 to 3 sterile Petri dishes with nutrient agar and agar nutrient with dishes Petri sterile 3 to 2 9) page see water, tap of L 1 in bleach household (page 23). (page covers Bring in extra kitchen items for students who students for items kitchen extra in Bring Parafilm or masking tape to seal dishes seal to tape masking or Parafilm swabs cotton Sterile marker Permanent liquid of ml (20 solution bleach Disinfectant gallons 2 — water Distilled Photocopy
their experiments: their hypothesis. their test to experiment an design Students’names should notputbetheonbags. thetypeitemof (e.g., sponge, canopener, etc.). Pose these questions to guide students through students guide to questions these Pose and hypothesis a develop team each Have eachAskstudent labelto their storage bagsby • • • • •
(Sterile or distilled water) distilled or (Sterile use? the kitchen item to the water? the to item kitchen the from bacteria transfer you can How to best be would water of kind What items? these in bacteria the of sample a get to way good a What’s dishes.) Petri the inoculate and items the (Swab bacteria? most/least the have items which out find you can How Why? bacteria? most/least the have might items kitchen of type Which sample the water.) the sample and bags the to water add or directly, item massage the item in the bag.) the in item the massage Develop, Hypothesize, and Conduct Experiment Conduct and Hypothesize, Develop, for each student each for Outline Report Lab
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design their experiment. their design 8). page (see dishes Petri inoculated of handling the especially untouched. half other the Leave water. distilled with plate control the of half swab water, the in bacteria for test 9). page (see plates agar inoculate Let the students conduct their experiments. experiments. their conduct students the Let and hypothesis their develop team each Let safety, lab of rules important the Review To plate. control a of importance the Discuss and water the sample to how Demonstrate • • • SAFETY
• • • • (Not necessarily) (Not samples? introducing new bacteria to the test the to bacteria new introducing not you’re sure be you can How present? are bacteria that indication an water the of appearance the Is clean.) appear will bags other in Water dirty. very appear will bags some in water (The item? the squeeze/massage you after like look water the does What a control bag with distilled or sterile water.) sterile or distilled with bag control a
experiment. Wash your hands your Wash 9). page (see lab the in working after and before surfaces lab all Disinfect bleachsolution after using it(see page 9). completed,orsoak each Petri dish ina safetechniques after the experiment is Destroyall disposable Petri dishes using pathogens. dangerous be could organisms Some it. in growing organisms with dish a open to never students Remind tape. masking or Parafilm with dishes Petri inoculated all Seal FIRST
(Use sterile plates and swabs. Use swabs. and plates sterile (Use and before the lab the after
CROSSED UP! 4 E L U D HOME RETAILAND O M
LAB 3 Observe and Record Results
PROCEDURE 1. Have teams observe their Petri dishes and • Could bacteria transfer from kitchen record the results on a data table. items to your food? Your hands? What 2. Ask each team to present their findings to might happen in these cases? the class. List the class results and have the • Why do certain kitchen items have students compare their findings to the “Most more bacterial growth than others? Bac” and “Least Bac” lists from Lab 1. (Be sure • How do the data you collected relate to to focus the discussion on the categories of the 4 Cs of Food Safety? Which of the items and not specific items.) 4 Cs? 3. Pose questions to guide students through a • How could you reduce the bacteria on discussion. For example: the items you tested? • How did your original lists compare • What are your suggestions for to the test results? Were there any avoiding cross-contamination in the surprises? What are your conclusions? kitchen? • What advice would you give to family members to help them prevent the spread of foodborne bacteria?
INSTANT REPLAY Time to review and summarize.
1. Did you find any bacteria? Where? Were you surprised with your findings? Why or why not? 2. Why is it a problem to find bacteria on a kitchen sponge, dish cloth, dish towel, etc.? (Bacteria from these items can spread to other surfaces and then to food.) 3. To what surfaces can the bacteria spread? (Cutting boards, utensils, kitchen equipment, countertops, etc.) How can bacteria spread from your hands to other things? (Bacteria can spread from your hands to other things when contaminated hands touch those surfaces.) 4. What can you do to prevent cross-contamination? (Wash your hands thoroughly, frequently wash sponges, dish cloths, dish towels, cutting boards, countertops, and cooking utensils with hot, soapy water.) 5. What can you personally do to reduce the spread of bacteria in your kitchen at home? (Follow the 4 Cs — especially Clean and Combat Cross-Contamination. See the 4 Cs section in the Food Safety A to Z Reference Guide.) 6. Did you discover that you were “guilty” of any unsafe practices in the kitchen? If so, what’s your strategy for correcting those unsafe practices? 7. How do your findings from this lab relate to the Bacteria Everywhere lab in Module 1 — Understanding Bacteria? (They show that bacteria are everywhere and can spread from hands to surfaces and to food.)
FOOD SAFETY 65 M O D U L E 4 66 RETAIL AND HOME CROSSED UP! EXTENSIONS cleaning. proper through controlled be can bacteria of spread The food. to even and hands, to items kitchen from spread can Bacteria SUMMARY • • •
Y T E F A S D O O F kitchens. Tally the answers. answers. the Tally kitchens. their survey to neighbors or relatives, friends, members, family 5 least at to survey the Give investigation. your of results the on findings from this experiment. this from findings your to relates pathogen foodborne your the in cross-contamination prevent to how explaining page Web or brochure safety” CA kitchen. Develop a Home Food Safety Survey based Survey Safety Food Home a Develop R how record to portfolio food-safety your Use “kitchen a develop results, survey the Using EE R N O I T C E N N O C Food Safety A to Z Reference Guide Reference Z to A Safety Food • • action! in scientists real-life See
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Web sites: Web Laboratory Exercises for Microbiology for Exercises Laboratory video Safety Food for Quest the and X Dr. Guide Reference Z to A Safety Food McGraw-Hill: Boston, MA (1999). MA Boston, McGraw-Hill: WCB Prescott. L. and J., Harley, Edition, 4th the 4 Cs section on pages 54–63. pages on section Cs 4 the see Also Survey.) and Pathogen, Handwashing, Safety, Food Illness, Foodborne Contamination, Safety Initiative/CDC Safety educators/ccp.cfm?articleID=62&parent=2 http://www.extension.iastate.edu/foodsafety/ University www.cfsan.fda.gov/~dms/fdkitchn.html DVD parent=2 educators/tensteps.cfm?articleID=48& http://www.extension.iastate.edu/foodsafety/ University www.fightbac.org www.foodsafety.gov firstaid_safe/index.html http://www.kidshealth.org/parent/ www.cfsan.fda.gov/~dms/fse-t-f.html USDA and http://www.cfsan.fda.gov/~dms/wh-food.html www.cdc.gov/foodsafety The Consumer Control Point Kitchen/Iowa State Kitchen/Iowa Point Control Consumer The Test?/FDA Partnership for Food Safety Education Safety Food for Partnership (See the following terms — terms following the (See
Module 4 – Retail and Home and Retail – 4 Module FS303 Code: www.scilinks.org to: Go E-coli Keyword: Bacteria, , / M O D U L E 4 RETAIL AND HOME 67
the lab. Let’s begin . after before and Outbreak Alert activity on FOOD SAFETY FIRST Dirty hands are one of the quickest ways to spread harmful bacteria and expose yourself and others to the risk of foodborne illness. Careful attention to washing hands thoroughly is essential for good health. FOOD SAFETY FOOD SAFETY CONNECTION Seal all inoculated Petri dishes with Parafilm or masking tape. Remind students never to open a dish with organisms growing in it. pathogens. be dangerous could organisms Some Destroy all disposable Petri dishes using safe techniques after the experiment is completed, or soak each used Petri dish in a bleach solution (see page 9). Disinfect all lab surfaces before and after working in the lab (see page 9). Wash your hands Would you want to eat a sandwich made by by made sandwich a eat to want you Would Why? hands? their wash didn’t who people Have you ever seen signs in restaurant bathrooms stating, “Employees must wash hands before returning to work”? Why are these signs so important? (One of the most common ways to transmit foodborne bacteria is by using the bathroom, not properly washing your hands, and then touching food.) a foodworker who did not properly wash his hands, see the pages 73–77.
Gather a collection of materials for students to Put Glo-Germ™ (or cooking oil and cinnamon on use in their lab designs. your right hand just before the students enter the classroom. • • • •
SAFETY Note: For a real-life outbreak case involving We know that handwashing is extremely important. Today we’re going to do a scientific investigation to learn more about the role handwashing plays in helping keep us healthy and our food safe • • • our investigation . . . ADVANCE PREPARATION ADVANCE • • (Now (Now
is on your hand.) TM (Let the students discuss
Two Two 45-minute class periods
Time: Time: HANDS OFF, BACTERIA! OFF, HANDS
Cinnamon, along with cooking oil can can oil cooking with along Cinnamon, and Glo-Germ™ of place in used be rub cinnamon, using If light. ultraviolet your over all oil cooking of tablespoon 1 Sprinkle coated. completely until hands and hands on cinnamon of teaspoon 1 distributed. evenly it’s until around it rub bacteria. represent can cinnamon The P I T Do you think your hands have picked up bacteria recently? What have you touched since then? What have you touched in the past 2 hours? In the past 4 hours? When was the last time you washed your How many people or surfaces have come in contact with my “bacteria” without coming in contact with me? hands? the things they touched in the last few hours. Hopefully, someone will remember that you shook everyone’s hand.) hands your to bacteria spread I have Could out. find Let’s handshake? my through take out the ultraviolet light and let the students students the let and light ultraviolet the out take surfaces.) classroom and hands their examine Petri dishes with nutrient agar and covers for each team of 3 to 4 students (optional) X and the Quest Dr. for Food Safety video/DVD, Module 4 — Retail and Home Paper towels A source of running water Handwashing soap Glo-Germ™ (see Resources on page 86) and ultraviolet light This experiment challenges students to identify to identify students challenges experiment This design will They in handwashing. involved variables washing for method best the to discover experiments of bacteria. spread the to reduce hands their data. the present and analyze also will Students LAB AT A GLANCE LAB AT A
INTRODUCTION When the students get settled, ask them: • • • Greet each student with a hearty handshake as he/she enters the classroom. (Only you know at this point that Glo-Germ • • • • • • • • • MATERIALS GETTING STARTED M O D U L E 4 68 RETAIL AND HOME HANDS OFF, BACTERIA! HANDS OFF, LAB 2 LAB sample hands before and after handwashing. after and before hands sample to dishes Petri use also can Students Note: 2. 1. LAB 1 LAB 2. 1. PROCEDURE PROCEDURE Y T E F A S D O O F Have students form teams of 3 to 4 students. 4 to 3 of teams form students Have following: the students Ask • • their conclusions. their write teams the having by lab the Complete experiments. their from data the show to graph or chart a create then and results, their record and observe to students Ask experiments. their conduct students Have mostbacteria: whichtheoffollowing actions getridtheof oilrepresentto “bacteria.” Students cantest ultravioletlight cinnamonor andcooking techniques,youcanuse Glo-Germ™ andan (Todetermine themost effective handwashing for washing their hands. their washing for method best the discover to experiment an develop students Have rinsing.) just versus hands scrubbing water, the of temperature the hands, washing spent time the soap, no or soap using washing, not or (Washing handwashing has been effective? been has handwashing not or whether test we could How handwashing? in involved variables different the of some are What – – – –
of time for effective handwashing) effective for time of amount recommended the is seconds (20 scrubbing spent time of length soap using not versus soap using hands scrubbing not versus scrubbing water hot versus warm versus cold Conduct the Experiment and Experiment the Conduct Design the Experiment the Design
Record and Report Results Report and Record
4. 3. 3. handwashing hypothesis. handwashing own their investigate can they or bacteria, reducing in techniques handwashing different of effectiveness the habits, handwashing poor by spread are germs how show to choose can They handwashing. investigate to activity or experiment an design to team each Ask experimental designs if they wish to. wish they if designs experimental and hypotheses their revise to time teams the give discussion, class the After test. suggested each of merits the discuss to students all Encourage class. the to design experimental and hypothesis their present team each Let findings. their behind principle scientific the include to them Challenge use. to plan they procedure the and hypothesis, question, research their down write students Have science behind their discoveries. their behind science the explain to students Remind problems. those avoid to time next do would they what and had have may they problems any include to students Encourage experiments. their of results the present teams the Have ?DID
4 M O D U L E RETAIL AND HOME 69
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. Food Food HANDS OFF, OFF, HANDS BACTERIA! For more handwashing tips, tips, handwashing more For Raw meat, poultry, eggs, and Animals such as dogs, cats, turtles, snakes, and birds; and Diapers; seafood; Soil
hands before preparing food. Your diarrhea! infant cause could the from bacteria up pick can hands bacteria spread and things following baby: the to – – – – 20% of consumers don’t wash their you hands, your wash don’t you If FOOD SAFETY
Safety A to Z Reference Guide Z Reference A to Safety Note: the in section 4 Cs the see • • (They can spread from person to person, from people to Module 4 — Retail and Home handling food and after after and food handling after and and
Time Time to review and summarize. before Can you think of other things that you touch that contribute to the spread of (Our hands are in contact with bacteria in all settings. It’s necessary to wash them just before food preparation, whether at home or in a retail setting.) The Barkley family learned about the importance of washing their hands. to dinner? eat down sat they before hands their contaminated have could What Why is handwashing so important both at home and in the retail setting? bacteria? (Students should contribute their own answers.) (Playing with the dog, sneezing into hands, taking out the garbage, and playing basketball) playing and garbage, the out taking hands, into sneezing dog, the with (Playing How do bacteria spread? foods and objects.) What methods worked best to remove “bacteria” from your hands? Why do certain methods (e.g., scrubbing time, use of soap, etc.) work better to remove bacteria than others? handwashing? Did your experiment give you any ideas for conducting further research on
TIME TO TUNE IN . . . • Show video/DVD Module 4, Part 2 — Home (Time: 2 minutes). • • PART 2 — HOME Let’s rejoin Dr. X to see why he’s so concerned about a problem in Sector 17 1. 2. 3. 4. ALWAYS wash hands after touching raw meat, meat, raw touching after hands wash ALWAYS produce. fresh unwashed or eggs, seafood, poultry, Wash your hands with hot, soapy water (for at least at least (for water soapy hot, with hands your Wash 20 seconds) Make sure there’s handwashing soap and paper towels or clean cloth towels at every sink in your handling and diapers, changing bathroom, the using fingernails, wrists, hands, scrub Thoroughly pets. a with hands dry and Rinse fingers. in between and towel. cloth or a clean towel paper home.
• • Use these tips to keep your hands squeaky clean! squeaky hands your keep to tips these Use • away. Hot running water washes away suspended dirt and soils that trap germs. The soap suspends dirt and soils. The rubbing motion helps pull dirt and greasy and oily soils free from your skin so germs can be washed
• • • SOAP + SCRUBBING ACTION + HOT WATER = CLEAN HANDS! = CLEAN WATER + HOT ACTION + SCRUBBING SOAP S P I T R E G N I F INSTANT REPLAY INSTANT M O D U L E 4 70 RETAIL AND HOME HANDS OFF,BACTERIA! • • • • EXTENSIONS hands. withhot,soapy water removes bacteria from manythings every day.Thorough handwashing exposedmicroorganismsto because theytouch Handsareonepart theof body that are most SUMMARY activity (Module 2) with the rest of the class. the of rest the with 2) (Module activity Food of Chain the from charts journey food their share to students for time It’s
Y T E F A S D O O F CAR safety food your in data the record and pathogen foodborne your to activity this of results the Relate policies. handwashing their out find to office doctor’s or center health local a Contact safety. food to relation in activity Glo-Germ™ the Demonstrate etc. group, PTA meeting, Scout Boy or Girl home, nursing a preschool, or school elementary an at talk to appointment an up Set children. young for handwashing on brochure a Create EE R N O I T C E N N O C Food Safety A to Z Reference Guide Reference Z to A Safety Food • • action! in scientists real-life See
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What Are Germs?/Kids Health Germs?/Kids Are What Partnership for Food Safety Education Safety Food for Partnership • • • RESOURCES
Web sites: Web video Safety Food for Quest the and X Dr. Guide Reference Z to A Safety Food germs_prt.htm www.kidshealth.org/kid/talk/qa/ post1c.html www.foodsafety.gov wash_hands.htm www.fda.gov/oc/opacom/kids/html/ DVD 54–63. www.cleaning101.org/sdakids www.fightbac.org r2k0306c.htm www.cdc.gov/od/oc/media/pressrel/ wash_hands_prt.htm www.kidshealth.org/kid/talk/qa/ Pathogen.) Also see the 4 Cs section on pages on section Cs 4 the see Also Pathogen.) and Handwashing, Germ, Safety, Food Illness, — terms following the (See http://www.cfs.purdue.edu/safefood/foodsafety/ University Sheet/Purdue Fact Handwashing Information Safety Food Government to Gateway Kids/FDA for Quiz Safety Food Association Detergent and Soap Corner/The Kids SDA The Important?/CDC Handwashing is Why Health Hands?/Kids My Wash To Need I Do Why
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outbreak. Are you . Foodborne Bacteria, / OUTBREAK AND FUTURE TECHNOLOGY 5 E L U D O M
ABOUT THE MODULE Module 5 — Outbreak and Future Technology — takes a look at how technology and unexpected discoveries can benefit us in keeping our food safe.
Outbreak Alert (Shigella) — investigates an outbreak in order to determine its source.
Beef Blasters — explores how one scientist’s experiment led to an unexpected discovery.
SCIENCE CONTENT
This section explains the specific science concepts presented in Module 5 of the video/DVD, including fascinating facts relative to the module. Read this section before watching the video module or conducting the activities and experiments.
OUTBREAK Even though our food supply is the safest in the world, we face new challenges as we import food from all over the world, as new pathogens emerge, and as familiar ones grow resistant to treatment. Foods reaching your table today are produced, processed, and distributed very differently from even a decade ago. Food from a single source may be rapidly distributed to communities across the nation, making it more difficult to detect a disease outbreak caused by contaminated food. Just as food can now be rapidly distributed, technology is allowing us to keep track of foodborne outbreaks across the United States.
PulseNet Using molecular technology and a sophisticated computer system, epidemiologists can now rapidly assess whether a widespread food incident is underway, and they can trace the source of the problem by identifying distinctive fingerprint patterns of pathogens like E. coli O157:H7.
PulseNet is a way scientists are able to link microorganisms from different places associated with an outbreak to see if they have a common origin. Local laboratories participating in PulseNet perform DNA fingerprinting on bacteria that Pulse-Field Gel Electrophoresis have caused illness. Microbiologists extract DNA from the microorganism and then pulse an electrical current through that material. The pattern, or fingerprints, received by the currents is then transmitted through a networked computer system to the Centers for Disease Control and Prevention (CDC).
FOOD SAFETY 71 M O D U L E 5 72 OUTBREAK AND FUTURE TECHNOLOGY SCIENCE CONTENT DNA fingerprinting the experiment. the Dr.demonstrates Solomon beef expert beef Dr.exploding- the — Solomon Y T E F A S D O O F G N I T A N I C S A F • •
success. blasting experiment was a was experiment blasting beef- the before explosions 44 and months 4 took It year. every States United the in occur illnesses foodborne of cases million 76 FUTURE TECHNOLOGY FUTURE PulseNet (cont’d.) PulseNet Exploding Beef Exploding
an added bonus! added an was discovery This 60%. to 40 by bacteria harmful eliminating also but meat, the tenderizing only not was beef the to pressure hydrodynamic applying that discovered scientists way, the Along beef. the tenderizes pressure hydrodynamic the Thus, not. are fat and tissue muscle the and water, 75% about is Beef match. acoustical an not is that anything tear and water, the with match acoustic an is that anything through travel explosion the by created waves shock The explosives. detonated and trashcans, the buried trashcans, the inside water in meat suspended they Then trashcans. of bottom the in steel put they concept, the explore To water. in submerged meat of piece a tenderize could water in off set explosive an by unleashed waves shock that suggested theory The designer. weapons nuclear retired a from came that theory a explore to requested been had Maryland in Service Research Agricultural USDA’s at scientists Research outbreaks. future prevent to taken be will measures and market the off taken be will food the found, is source the If outbreak. the stop and problem the of source the trace to immediately begin can investigation An outbreak. multi-state possible a of participants PulseNet alert will computers CDC match, locations different in laboratories by submitted patterns If S T C A F 5 M O D U L E OUTBREAK AND FUTURE TECHNOLOGY 73 How
Food Safety bacterium. Ask: Shigella Here’s What the Public Health Officials FOOD SAFETY Outbreak Pulse-Field Gel Electrophoresis PulseNet (also see the step-by-step process for tracing a food implicated in a foodborne illness outbreak) – – – – Shigella Photocopy Did (page 77) for each team. A to Z Reference Guide: For background information on outbreaks, read about the following in the
would you investigate this case to find out how the outbreak got started? Continue to engage the students by telling them that they are FBI (FoodBorne Illness) Investigators in Suffolk County, New York. They’ve just received notice that 21 people in the county have become ill with similar symptoms (nausea, vomiting, diarrhea, cramps, and fever). The illnesses occurred over a 1-month period — from November 8 to December 8. The sick persons have tested positive for the • ADVANCE PREPARATION • Although our food supply is one of the safest in the the in safest the of one is supply food our Although It’s occur. do outbreaks illness foodborne world, foodborne of symptoms the of aware be to important the If severe. are symptoms if a doctor see and illness foodborne of presence the identifies lab clinical local the to sent are results the test, a patient’s in bacteria When testing. further for department health state of network a national there’s occur, do outbreaks helps that PulseNet, as such laboratories, health public states. multiple in outbreak an detect to FOOD SAFETY FOOD SAFETY CONNECTION You’re (Shigella)
One Time: 45-minute class period OUTBREAK ALERT ALERT OUTBREAK Module 5 — Outbreak and Future Technology Dr. X and the Quest for Food Safety video/DVD, ACTIVITY AT A GLANCE ACTIVITY foodborne a real-life analyze will Students role the assume will They outbreak. illness to investigators Illness) (FoodBorne of FBI questions the identify and steps the out plot of source to the to get in order to ask and discuss will Students outbreak. the to approaches investigative their compare investigation. health public actual the
INTRODUCTION GETTING STARTED sitting in your office. All of a sudden, red lights are flashing! You hear, “ring,” “ring,” “ring” all around you. What’s going on? Then finally you realize that this flutter of red lights and constant ringing is your telephone — it’s ringing off the hook. Could it be . . . an outbreak? Motivate your students with this scenario: MATERIALS • Food-safety portfolios (for each student) • M O D U L E 5 74 OUTBREAK AND FUTURE TECHNOLOGY OUTBREAK ALERT Discussand8. compile classa list whatof would investigation their share group each have Then 7. sure Make steps. their up write teams the Have 6. 5. 4. 3. Illness) (FoodBorne FBI as that students 2. Inform groups. 4 or 1. 3 into students the Divide PROCEDURE Y T E F A S D O O F “How” of this case. For example: For case. this of “How” and “Why” the solve then “W,” each on specifics more with up come should They case. the about details more discover to team each Challenge “How”). plus “Why,” and “When,” “Where,” “What,” (“Who,” “Ws” 5 the of form the in portfolio food-safety their in it record and case? students: Ask outbreak. this investigate to take would they steps the identify to colleagues their with work to job their it’s investigators, “Ws” were given in the teacher introduction. teacher the in given were “Ws” the theoutbreak occurred, whowhator transmitted thebemost probable conclusions wheretoas class. the with conclusions their and steps step. each number they students: Ask formulate their own strategies. own their formulate to students the allow first but answers), the and clues for right at box (see clues them give also can you time, to time From 76). page on section Resources the (see Shigella and outbreaks about research conduct can students way, the along them help To first? correcttheproblem? occurred.Thenask: • • • TIP have occurred? have outbreak this could County Suffolk in Where is How is What scientific questioning and a step-by-step a and questioning scientific logical, on based that’s conclusion a at arrive to them for is thing important The 77. page on investigation actual the as conclusions or steps exact the with up come not do students the if okay It’s process. Shigella — — Why 8 December to 8 November — When York New County, Suffolk — Where — ill became who people 21 What — Who Have them analyze the existing data existing the analyze them Have transmitted? Shigella Shigella? bacterium, andwhythe outbreak What do you know about this about know you do What What do you need to find out find to need you do What ? Shigella Whatwouldtoyou do (Shigella) bacterium 4 of the of 4 Note: Clue #9 Clue #8 Clue #7 Clue #6 Clue #5 Clue #4 Clue #3 Clue Clue #10 Clue Clue #2 Clue Clue #1 Clue Where does this information lead you? lead information this does Where How is it transmitted? it is How Shigella? about know you do What (A food(Aworker probably caused theoutbreak.) then handles food.) handles then and hands her or his wash doesn’t bathroom, the using after who, worker food sick a ( Who would you talk to? talk you would Who outbreaks are usually caused by caused usually are outbreaks Shigella latereaten bythe 21people who became sick). hisorher hands and handled food that was byfooda worker who did not properly wash What would you do next? do you would What hands.) her or his wash properly not did and question in days the on sick was who worker food a probably was (There you? lead information this would Where particularlyhandwashing procedures?) (Whatare your restaurant’s policies, (Wereyou sick on those days?) (Whatwas your work schedule?) (Wereyou working on the days in question?) workers? food the ask you would What establishment) (foodworkers at the implicated food to? talk you would else Who outbreak.) the in implicated be might food what and occurred have might outbreak the where you tell would (It you? lead information this would Where symptoms?) experience first you did (When eat?) you did (What sick?) got you before eat you did (Where people? sick the ask you would What people) sick 21 (the suspectthat the (AsFoodBornea Illness investigator, you would you? lead information this does where match, results the If people.) sick 21 the from results the match results test her or his if see to bacterium (Test the food worker for the for worker food the (Test bacterium. particular a to exposed been have they if determine to food and people test can Officials Health Public Tip: Shigella outbreakwas caused Shigella
5 M O D U L E OUTBREAK AND FUTURE TECHNOLOGY 75 (Shigella) FOOD SAFETY OUTBREAK ALERT ALERT OUTBREAK all times.) in the Instant Replay below. 10. Then have students discuss the questions Module 5 — Outbreak and Technology Future Shigella outbreak was a carrier of the bacterium when the French fries Beef Blasters activity. Time Time to review and summarize. PulseNet The connection between PulseNet and DNA Pulse-Field Gel Electrophoresis (PFGE) How the Internet aids in outbreak investigations • • • • restaurants? observe the restaurant’s surroundings. If it’s not up to your cleanliness standards, you might want to eat somewhere else.) (The restaurant manager should not have come to work if he was sick. The appropriate handwashing supplies should have been provided in the kitchen and employee and customer restrooms. The manager should have washed his hands properly.) What can you do to make sure your food is safe when you eat at fast-food Why is it important to wash hands even when you don’t feel sick? without experiencing the symptoms. Therefore, if you don’t properly wash your hands, you could spread the bacterium from your hands to foods. For example, the store manager in the Why is it important for public health officials to investigate foodborne illness outbreaks? and prevents additional people from getting sick or dying from consuming harmful foodborne bacteria. Also, what public health officials learn from these outbreaks can help prevent future outbreaks.) How could this outbreak have been prevented? were contaminated, but he didn’t experience the symptoms until several days later. Proper handwashing is of extreme importance at
TIME TO TUNE IN . . . Show video/DVD Module 5 — Outbreak and Future Technology, but stop the video right after Dr. Paul’s segment (Time: 3 minutes). The rest of the video module will be shown at the end of the Now it’s time to meet scientists who will share some of the tools they have for investigating FBI outbreaks. Watch for what they have to say about: (When you go out to eat, always wash your hands properly before eating food. Also, 4. 3. 2. 1. (Even though you may not feel sick, you could be a carrier of a foodborne bacterium (Early detection of an outbreak helps determine the possible source of that outbreak real-life, step-by-step process that Public Health Health Public that process step-by-step real-life, conducted York, New County, in Suffolk Officials and approach class the Compare 77). page (see Are investigation. actual the with conclusions Differences? similarities? there PROCEDURE PROCEDURE (cont’d.) INSTANT REPLAY INSTANT After you have compiled the class list, review the the review list, class the compiled 9. have you After M O D U L E 5 76 OUTBREAK AND FUTURE TECHNOLOGY OUTBREAK ALERT and customers. and employees, managers, foodservice manufacturers, distributors, ranchers, farmers, including bacteria, harmful from safe food our keeping from hands to foods. to hands from spreading from bacteria preventing in precautions important most the of one is handwashing EXTENSIONS handwashing. proper especially practices, food-handling safe follow doesn’t she or he establishment,if people multiple infect can Oneperson, working infoodservicea SUMMARY Relate your pathogen to this activity and record record and activity this to pathogen your Relate • Webat: Safety site Food CDC’s out Check • solution. and case outbreak own Writeyour • the In • Y T E F A S D O O F prepare a report, including the following: the including report, a prepare the information in your food-safety your in information the portfolio. food-safety your in discoveries any Include outbreaks. illness foodborne recent any in involved was pathogen foodborne your if see to investigations”) www.cdc.gov/foodsafety it. solve and investigate class the have and case the out act Then gov/ncidod/dbmd/pulsenet/pulsenet.htm Webat: PulseNet site the Investigate states. multiple in outbreak foodborne a detect better to “fingerprinting” DNA performs that laboratories local of network national a PulseNet, about learned you video/DVD, – How do you think PulseNet will change in the in change will PulseNet think you do How – CAR foodborne your tracking currently PulseNet Is – to used been “fingerprinting” DNA has How – work? PFGE by “fingerprinting” DNA does How – PulseNet? is What – EE next 10 years? 10 next pathogen? R illness? foodborne prevent N O I T C E N N O C Dr. X and the Quest for Food Safety Food for Dr.Quest the and X Food Safety A to Z Reference Guide Reference Z to A Safety Food • • action! in scientists real-life See
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Pathogen Identified Location and Food Verified 1: Between November 8 and December 8, 1994, 12: Health inspectors request that the restaurant’s 21 people experiencing symptoms (nausea, vomiting, operators advise all employees who worked on the diarrhea, cramps, and fever) go to the doctor. days in question to submit to a stool sample. Four 2: Doctors make an initial diagnosis, and stool cultures employees quit rather than submit a sample. from the patient are sent to a clinical laboratory. 13: Fifty-one stool samples were provided. All but 3 samples 3: At the lab, medical tests are done on the stool were negative. One was positive for Streptococcus, one cultures. The lab determines the presence of the was positive for Salmonella, and one was positive for Shigella bacterium. Shigella. These 3 employees were restricted from work until 3 consecutive, negative stool samples were obtained. 4: An isolate of the bacterial culture is sent to the The one positive sample for Shigella was collected from state health department lab for further testing. the store manager who had first stated that he had 5: The health department sends the results to the Bureau not been ill. He later admitted that he had experienced of Infectious Disease Control in Suffolk County. gastrointestinal illness on December 8, 1994. Investigation Expanded 14: When a positive Shigella was obtained from the 6: Due to the unusual cluster of cases, the Bureau manager, a copy of his work schedule was obtained realizes that this is not an isolated case, but an to determine if he worked on the dates and times of outbreak. On December 12, 1994, the investigation the suspect meal. It was found that his work schedule begins. matched 2 of the 4 suspect meals. 7: Health officials interview the 21 sick people. They Conclusion discover that 17 of the 21 people affected fell into 15: The health department makes a conclusion that the one of three categories: illnesses originated at the restaurant based on the • They ate at the same fast-food restaurant 1 or 2 following factors: days prior to the symptoms occurring; • Shigella outbreaks are usually caused by sick food • They were members of a family who ate foods workers who, after using the bathroom, don’t wash prepared at the restaurant 1 or 2 days before a their hands and then handle food. family member became ill; • The sick food worker first said that he was not sick • They had close personal contact with families who and later stated that he experienced symptoms on had eaten at the restaurant 1 or 2 days before December 8, 1994. This was several days after the last a family member became ill, but they did not, customer in the outbreak became sick, indicating that personally, eat at the restaurant. he may have been spreading the bacterium before he actually experienced the symptoms. The food worker Possible Location and Food Identified may also have been mildly sick, but didn’t realize it. 8: Officials give the affected families a questionnaire. French fries were the only product common to all the Two of the 5 families return the questionnaire. The • sick people. Normally, very little hand contact occurs questionnaire reveals that 4 of the 5 families who in preparing and dispensing French fries, because the had eaten at the restaurant developed symptoms fries are scooped with a utensil. However, the product within the 2-to-3 day incubation period. The fifth is handled by front-counter personnel who do not use family had close personal contact with one of the disposable gloves as a barrier to hand contact with families that had eaten at the restaurant. French the food. It’s not unusual for fries that fall out of the fries were the only common food eaten by the sick cardboard holders to be picked up with bare hands people and their families. and tossed back into the French fry bin. Furthermore, 9: Health officials interview the employees who worked the cardboard containers are stored flat and must in the afternoon, because the suspect meals were be “opened” to accept fries. These containers are served in the afternoon. frequently opened and carried with bare hands that 10: Health officials take stool samples from the touch the outside and inside of the container. afternoon employees for bacteriological examination. 11: Health officials inspect the restaurant. During the inspection, they discover that the rear kitchen handwashing sink and the customer and employee restrooms lack sanitary hand towels.
Note: This investigation did not confirm the association between the restaurant and the Shigella bacterium. However, the bacteria test results and the presence of an employee in the restaurant who tested positive for the same type of Shigella that infected the families who ate at the restaurant, suggest that the outbreak was caused by foods eaten at the restaurant. Foodborne illness outbreaks are very difficult to track and public health officials can only draw conclusions based on the information they obtain from sick persons, food establishments, and test results.
FOOD SAFETY 77 M O D U L E 5 78 OUTBREAK AND FUTURE TECHNOLOGY PROCEDURE 2. 1. Blaster” steak? Blaster” “Beef a about How Burger? Blaster” “Beef a eat you Would term? this see you when of Ask: board. the on Blasters” “Beef term the writing by lesson this Begin • MATERIALS • ADVANCE PREPARATION INTRODUCTION GETTING STARTED
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video/DVD, Safety Food for Quest the and X Dr. of copies Make questionnaire (see pages 80-81) for each student. each for 80-81) pages (see questionnaire Module 5 — Outbreak and Future Technology Technology Future and Outbreak — 5 Module share their knowledge with the rest of the class. the of rest the with knowledge their share and questions these on “experts” the become will Students questions. 2 team each Assign student. each to questions the distribute Then teams. “expert” 5 into students Divide One 45-minute class period class 45-minute Time:One BEEF BLASTERS Solomon’s segment (Time: 3 minutes). 3 (Time: segment Solomon’s Dr. with Begin Technology. Future and Outbreak — 5 Module video/DVD Show activities. explosive his demonstrates and theory Hydrodyne the explains he as action in Solomon Dr. see Let’s TIME TO TUNE IN . . . . . IN TO TUNE TIME article and article Blasters Beef Beef Bla Beef
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video/DVD Module 5 — Outbreak and Future Technology www.meatami.com www.foodsafety.gov Meat Science Research Laboratory, USDA http://www.anri.barc.usda.gov/MSRL.html Information R A RESOURCES • • • American Meat Institute (AMI) Gateway to Government Food Safety C Food Safety A to Z Reference Guide Careers section). and career (see the waves kill harmful bacteria. of foods. Give explanations as to why your technology might work. recent history where discoveries were made unexpectedly (e.g., Alexander Fleming and the discovery of penicillin, Louis Pasteur and the discovery of pasteurization, the 3M Post-It Notes invention, and NASA discoveries). Identify scientists who might be considered maverick thinkers and worked in unconventional ways. Learn more about Dr. Solomon’s background Design a tool that could kill bacteria in a variety Give tentative explanations for how the shock Research additional examples in science or • • • EXTENSIONS • Scientists sometimes have unconventional ideas ideas unconventional have sometimes Scientists was article This ways. unique in them test and the and serendipity how of example a great a major play sometimes scientists of personality illustrates clearly it and discoveries, science in role case, this In enterprise. a human is science that beef, tenderize to how discovering to addition in to work also waves shock that found scientist the and on bacteria of amount the reduce significantly meat. the in SUMMARY BEEF BLASTERS By Wes Ishmael Contributing Editor – Beef Magazine™ January 2000
“What’s his background and how ou know it’s going to be a tough Launching A New Idea Y do we get hold of him?” day when your boss summons you “I don’t have any idea . . .,” said Since meeting Long in 1992, to meet with the office brass and in Solomon. Solomon has heard several versions come three agents from the FBI and In hindsight it’s easy to of how Long first conceived of three from Alcohol, Tobacco and understand how it was that tenderizing meat with explosives Firearms (ATF). They immediately Solomon left this interrogation as back in the ’60s. Suffice it to say, flash their badges and begin a much of a suspected terrorist as by the time Solomon entered the no-nonsense interrogation about why John Long. Keep in mind, this ARS picture, Long had his Hydrodyne you’re trying to acquire explosives, complex houses all kinds of pesky process and a prototype already and why none of your bosses know bacteria, parasites and the like. patented. anything about it. Plus, to meet Solomon is to believe The device today is a 7,000-lb. steel Never mind that you’re a research his creative thoughts must come tank that holds 282 gals. of water scientist at USDA’s 7,000-acre at the same frenetic pace as his and 400–600 lbs. of meat. The meat Agricultural Research Service (ARS) conversation. It’s easy to imagine is bagged and submerged in the tank. facility in Beltsville, MD, smack him chasing down the bottom line An explosive is suspended over the between Washington, DC, and without worrying about where a top of the meat, then detonated. Baltimore. cache of explosives was coming But Solomon was far from knowing
from. all of this when he traveled to an off- Developing the “Things weren’t going well,” site location in Virginia, armed with remembers Solomon. “Plus, John is meat, to witness his first Hydrodyne Hydrodyne, a pressure a very persistent guy, so he was still “shot” at tenderization. He was still trying to get me the explosives.” skeptical. process that tenderizes Solomon wasn’t familiar with the When Solomon arrived and saw meat and destroys requirements for buying explosives. these would-be pioneers taking So when a supplier enlisted by Long rubber trash cans out of their car, pathogens, is genuine contacted Solomon, his naivete he said, “No, no, that’s alright. I’ve cloak-and-dagger stuff. was all too obvious. The suspicious already got the meat in a cooler, we supplier turned him into the FBI. don’t need those.” The government agents told “No, you don’t understand,” they Solomon they would monitor his said, “This is our hydrodyne unit. activities as they tried to get a lead There is no reason to build the one Morse Solomon, research leader on this John Long fellow. They you saw the picture of until we know of the ARS meat science research told him he could accept phone that this works.” laboratory, tried to explain to the calls from Long but no packages. Solomon’s heart could have slipped agents that the explosives were for Solomon dodged Long’s calls for beneath an ant’s belly with room an experiment he was conducting two weeks. By this time, he was to spare. He believed the machine at the request of the Secretary pondering his career prospects and already existed, that his experiment of Agriculture’s office. They had his freedom. and expertise were only to determine requested his help designing an What seemed like a lifetime later, how well the process worked. experiment to prove their Hydrodyne Solomon was again called to the They buried the trash cans, theory – that shock waves unleashed office of his boss’s boss. This time detonated the explosives and raced by an explosive set off in water would there was just one FBI agent and back to the lab to see the results. “It tenderize a piece of meat submerged one ATF agent. didn’t work,” says Solomon. “There in the same water. “Let’s try this again,” said the wasn’t any change in the meat at all.” “Who exactly called you from the agents. “Do you know who John Long made a quick phone call to Secretary’s office?” asked the agents. Long is?” a physicist friend. Bemusedly, that “I wrote it down, but I don’t “I still don’t have any idea,” said friend informed him there was no remember off the top of my head,” Solomon. way the process would work without said Solomon. “Well, we do,” said the agents, steel in the container for shock-wave “Did you even verify that it was finally smiling. Turns out, Long reverberation. the Secretary’s office?” wondered is a retired CIA weapons designer They tried again, with steel in the the agents. with Pentagon clearance; he used to bottom of the trash cans. The results “I didn’t really see a reason to,” design nuclear weapons. He and were incredible. Basically, Solomon replied Solomon. his partner tracked Solomon down says you can take tough steaks, as “And who are you designing the via a former Assistant Secretary measured by Warner-Bratzler shear experiment for? Who is trying to of Agriculture. They and their force and, under the right conditions, deliver explosives to you?” demanded Hydrodyne idea were for real. hydrodynamic pressure technology the agents. can make them eat as tender as filet. “Some guy named John Long.” “The meat is softer than normal now working apart from ARS to Solomon and his crew uncovered when you take it out, but it firms perfect the process. At the same something even more startling. With back up in the cooler,” says time, Solomon and his research an added tweak, the process destroys Solomon. In taste panel work team continue to do their own pathogens. conducted by ARS researcher Brad experiments with a scaled down “Food safety is a bigger issue Berry, consumers detect the change version of the prototype and those than tenderness, and we’re getting in tenderness but no differences in trusty trash cans. a 40–60%* reduction in bacteria flavor or juiciness. Solomon adds, load with hydrodynamic pressure “In some studies with salted meat The Rest Is History, Almost technology,” says Solomon. That, (kosher processing), we’ve found plus increased tenderness for an With more steel in the actual this process also helps preserve the estimated 8–10¢/lb. Hydrodyne unit, researchers cherry red color.” Understandably, Solomon says believed its performance had to In round numbers, Solomon meat processors are excited about outpace the trash cans. So far, explains they’ve seen everything from the prospects, especially considering it hasn’t. Researchers reduced a 20% to 60% increase in tenderness. how well Hydrodynamic pressure shear force 37–57% in the original Part of that has to do with how stacks up when compared to other metal prototype, but effectiveness tender the meat is to begin with. The postmortem technologies that lessened as structural changes were process will not over-tenderize meat, require aging. But, Solomon says made to accommodate the force so it will not add anything to meat they’re not thrilled with a batch of the explosions. The last time that is already tender. system unless the batch could be Solomon tested the modified unit, What’s more, Solomon points at least 10 times larger than the tenderness gains had dropped to out, “With this process, not only 600 lbs. of meat held by the current 12–24%. All the while, the venerable does it reduce shear force values, prototype. trash can is increasing tenderness but it flattens out the tenderness With that in mind, Solomon and 33–67%. variation across the steak, making it his team of research scientists The jury is still out, but explosives consistently more tender.” envision an inline system that would experts from the army and navy For the record, Solomon says, the preserve the added effectiveness of think the differential may have to shock waves work because meat, the trash can explosion. He believes do with the fact that the sides of beef in this case, is 75% water. commercial application may be only the trash can actually explode out, “The shock waves travel through two years away. while an implosion occurs in the self- anything that is an acoustic match If it does become reality, chalk it contained unit. The theory is that the with the water (the water in the up as a good day for the U.S. beef explosion conjures up a shock wave beef). The things that are not an industry, and a long haul for one three times more powerful than the acoustic match (muscle tissue and scientist who dodged the long arm of implosion. intramuscular fat) are torn. That’s the law to make it possible. why the cuts have to be boneless As private industry and ARS or semi-boneless. The shock waves wrestle with the differences, shatter the bone and over-tenderize the tissue next to it,” he says. Armed with successful results, * Meat samples were examined immediately after HDP treatment. Shelf-life bacterial Long and his business partners populations in the samples showed a 3-log reduction (for example, they decreased from formed a company and constructed 300,000 colony-forming units to 300). Agricultural Research/December 2000 a $1.6 million prototype. He’s
Reprinted with permission from Beef Magazine™
Answer the following questions with your team:
1. What’s the science behind this story? 2. Do you consider Dr. Morse Solomon a scientist or an engineer? Explain. 3. What do you think are the characteristics of a scientist? 4. What’s the twist of science in relation to how research is conducted at the beginning of a study compared to the end results? 5. Do you know of any other examples in science or recent history where discoveries were made unexpectedly? Explain. 6. How do scientists get their ideas? 7. What’s the inter-relationship of the different sciences in reference to this experiment? 8. How does a scientist prove a theory to be correct? Who and by what means is it proven correct? 9. What happens after a scientist proves a theory to be correct? How does that theory become a reality and get put to use? 10. How do Dr. Solomon’s experiments relate to you? Time: Two 45-minute class periods EVALUATION ACTIVITY AT A GLANCE Day 1 — Create questions Day 2 — Play the game Based on the popular TV game show, “Who Wants to be a Millionaire?”, this activity allows students to put their food- safety knowledge to the test. It reinforces safe food handling practices, promotes cooperative learning, encourages EVALUATION class participation, and reviews the food safety unit in a fun, interactive way. On Day 1, students create their own evaluation questions based on what they’ve learned from the Dr. X and the Quest for Food Safety video/DVD, activities, and experiments. Then, on Day 2, they play the game, using the questions as an evaluation exercise.
GETTING STARTED ADVANCE PREPARATION MATERIALS • Read the game instructions. • Make copies of the game template for each Day 1 team. For Each Team of Students • Lose a Million Bacteria game template • Materials to make overhead transparencies and/or signs
Day 2 For the Class • Overhead projector • Raffle-style tickets with the same number on both ends • Drawing bowl • 2 chairs — one for the host and one for the contestant (placed at the front of the room like a game show set) For Each Team • Overhead transparencies or signs with food-safety questions • Signs to illustrate each bacterial level (1,000,000 / 750,000 / 500,000 / 250,000) • “Winner” and “Applause” signs (optional)
INTRODUCTION
You’ve heard of the popular TV game show, talking BACTERIA! Yes, it’s the Lose a “Who Wants to Be a Millionaire?” Well, now Million Bacteria game. Today we’re going it’s your turn to play! But in this game to prepare our questions for the game. we don’t win a million, we lose a million. Tomorrow you’ll have a chance to use your Don’t have a million to lose? Oh, yes you food-safety knowledge and lose a million do! We’re not talking dollars here, we’re bacteria!
82 FOOD SAFETY N O I T A U L A V E LOSE A MILLION BACTERIA
PROCEDURE
DAY 1 Create the Questions
1. Divide students into 5 teams, representing 6. Review the questions and answers with each each of the 5 Science and Our Food Supply team and help them select 4 questions (very modules — Understanding Bacteria, Farm, easy, easy, moderate, and challenging) to be Processing and Transportation, Retail and used for the game. Then write the correct Home, Outbreak and Future Technology. answers for these questions in the Answer Key 2. Give each team 1 game template. on the back of the template. 3. Challenge each team to create 8 questions 7. On Day 2 of the game, each team will conduct for their module based on what they learned the Lose a Million Bacteria game based on the from the video, activities, and experiments. questions they’ve created and selected for their Create 2 very easy, 2 easy, 2 moderate, and 2 module. Have the teams decide what roles challenging questions. their fellow teammates will play (e.g., asking questions, selecting contestants, displaying 4. Have teams write their questions on the questions, holding up signs, etc.). template in an order ranging from very easy to challenging. 8. Have each team prepare overhead transparencies or signs for each question, and 5. Write the correct and incorrect answers in the signs for applause, winner, bacterial levels, etc. alphabetical spaces provided on the template. 9. On Day 2, they’re ready to play the game! DAY 2 The Game
• The game is set up for 5 contestants with 5 sets answer, their round is finished. Then the host (5 modules) of food-safety questions. should draw another ticket. Continue until all • As students enter the classroom, give each one the module questions are answered. a numbered ticket. Have them tear the ticket 2. Each contestant can choose two lifelines during in half, place one half in the drawing bowl, and their round: keep the other half. • Ask a Friend — Students in the class who • The team for Module 1 will moderate the first believe they know the correct answer should round of the game. raise their hands. The contestant selects one • Read the following rules to the students, then student to give his or her answer. If there are have the Module 1 team draw a numbered no volunteers, the contestant draws a ticket ticket from the drawing bowl. The student with and the student with the matching ticket has the matching number is the first contestant! a chance to respond. Note: Students from the hosting team can’t • 50/50 and Try the Audience — Cover up 2 answer questions from their module. If a ticket of the incorrect answers. The host will ask the from a host team member is selected, draw class if the first remaining answer is correct. another ticket. Those who think it’s correct will stand. Those who think it’s incorrect will remain seated. The Rules Repeat for the last remaining answer. The contestant then selects his or her answer. 1. Each contestant has the opportunity to answer four food-safety questions. Before the host 3. After all the Module 1 questions are answered, reads each question, the level of bacteria to continue the game with teams for Module 2, 3, be reached should be displayed. The host 4, and 5. reads the question and four possible answers. For every correct answer, hold up the signs SUMMARY indicating the level of bacteria that has been The Lose a Million Bacteria game is an excellent decreased. The amount of bacteria decreases way to evaluate what your students have by 250,000 — from 1,000,000 to 750,000 to learned throughout the food-safety unit, but 500,000 to 250,000 to “Winner.” Optional: more importantly, it is a fun and exciting way Hold up an “Applause” sign for each correct to challenge them to think, create, interact, and answer. If the contestant gives an incorrect participate! FOOD SAFETY 83 CHALLENGING 7.
a. c. b. d.
8.
a. c. b. d.
ANSWER KEY
Fill in the correct answers to the 4 questions approved by your teacher.
Very Easy: 1.
Easy: 2.
Moderate: 3.
Challenging: 4.
Student Edition National Science Teachers Association Step Up to The Plate VERY EASY Put your food-safety knowledge to the test! Challenge your classmates with 1. food-safety questions based on what you’ve learned in the video, activities, and experiments.
The template below includes blank spaces for your questions, plus alphabetical a. c. blank spaces for one correct and 3 incorrect answers. Create 8 questions and b. d. correct answers based on what you learned in your module. Your teacher will help 2. you select the final 4 questions for the game based on level of difficulty, Very Easy – Easy – Moderate – Challenging. Then write 3 incorrect answers for each question. Think carefully about the incorrect answers — for the Very Easy questions, they can be obvious, for the Challenging questions, they should be more difficult. Here’s a. c. a sample model of the final questions for Module 1 — Understanding Bacteria (the b. d. correct answers are in boldface): EASY
1. Pathogens that were not previously known to cause human illness are called: 3. a. Energetic c. Emerging b. Egyptian d. Elemental 2. Which of these is not one of the 4 Cs of proper food-safety behavior? a. c. b. d. a. Clean c. Cook 4. b. Chill d. Contaminate 3. What food temperatures constitute the “Danger Zone”? a. 0° F – 32° F c. 140° F – 180° F b. 40° F – 140° F d. 180° F – 210° F a. c. b. d. 4. By what process does bacteria grow? MODERATE a. Binary Fission c. Pasteurization b. Acidification d. Irradiation 5.
Once you have written your questions and answers, your teacher will help you select 4 questions to challenge your classmates during the Lose a Million Bacteria a. c. game. Make sure you place all the correct answers for these questions in the b. d. answer key on the back of the game template. Are you ready? It’s time to play . . . the Lose a Million Bacteria game! 6.
Name of Module: — — — — — — — — — — — — — — — — — — — — — — a. c. b. d. RESOURCES Go for the gold! Check out the latest food-safety books, videos, and a host of other resources listed alphabetically.
Reference Books Science Catalogues and Supplies cont’d. Videos, Kits, and Brochures Bergey’s Manual of Determinative Fisher Science Education Discovery Education, the Institute of Bacteriology, edited by John G. Holt, www.fisheredu.com Food Technologists (IFT), and the IFT Ph.D., 9th edition, Lippincott Williams & To request a free catalogue, you can call Foundation partnered to develop a unique Wilkins, Philadelphia, PA (1993). Now only (800) 955-1177. Or, visit their Web site and program, designed to introduce high school available in public or college libraries. click on “catalog request.” (Shipping and students, teachers, counselors, and parents handling charges do not apply.) to the remarkable world of food science Bergey’s Manual of Systematic Materials are for grades 6 through 12. and technology, and the exciting career Bacteriology, edited by David Boone, opportunities in the field. Browse Richard Castenholz, and George Garrity, 2nd Flinn Scientific www.discoveryschool.com/foodscience to edition, Volume 1, Springer Verlag, New York, www.flinnsci.com freely download videos, profiles of professional NY (May 2001). Call 1-800-Springer (777- To request a free catalogue, you can call food scientists, lesson materials and 4643). ISBN # 0-387-98771-1. Springer Web (800) 452-1261. Or e-mail: [email protected] experiments, information about colleges and site: www.springer-ny.com. Materials are for grades 7 through 12. scholarships, and more. Hard copies of the The Coming Plague — Newly Emerging Glo Germ™ Kits multi-media kits (science focused, including Diseases in a World Out of Balance, www.glogerm.com 6 standards-based experiments; careers by Laurie Garrett, Farrar, Straus & Giroux, The Glo Germ™ company offers a variety of focused) are available for $10 each by emailing: New York, NY (1994) kits that help you teach handwashing, [email protected]. Bulk discounts are isolation techniques, aseptic techniques, and CRC Handbook of Laboratory Safety, available. general infection control. The handwashing by Keith A. Furr, 5th edition, CRC Press, Additional resources are available from IFT for kits include these main elements: a UV light Boca Raton, FL (2000) free at www.ift.org; follow the Education link (batteries included), powder, and gel. Preview to Teacher Resources. Here, you can “Find a Laboratory Exercises for Microbiology, the kits at their Web site. For all grades. Food Scientist” willing to speak to your class by John P. Harley and Lansing M. Prescott, 4th TO ORDER: Call the Glo Germ™ Company by entering your zip code. The videos “The edition, WCB McGraw-Hill, Boston, MA (1999) at (800) 842-6622. In Canada, you can call Great Food Fight” (13 minutes; food safety (800) 634-0770. Kits range from $49.95 and Laboratory Safety, by Diane O. focus for grades 4 through 12) and From up, plus shipping and handling. Fleming, 2nd edition, American Society for Concept to Consumer: Food Product Development Microbiology, Washington, DC (1995) Sargent-Welch (20 minutes) are accessible in Quicktime Power Unseen — How Microbes Rule www.sargentwelch.com and Real Media Player formats, complete the World, by Bernard Dixon, Oxford To request a free catalogue, you can write to with teachers guides and student handouts. University Press, New York, NY (1998) Sargent-Welch, P.O. Box 5229, Buffalo Grove, Download food science experiments, including IL 60089-5229. Or call (800) 727-4368. For the books: Food Chemistry, Enzymes in Food Typhoid Mary: Captive to the Public’s all grades. Systems, Microbiology in Food Systems (with Health, by Judith Walzer Leavitt, Beacon a fermentation focus), play online games, and Press, Boston, MA (1996) 3M™ Petrifilm™ Plates www.3M.com/microbiology more. The 3M™ Petrifilm™ Plates start-up package Science Catalogues and Supplies contains everything you need to begin doing your own experiment testing. All you do is National Science Teachers Association inoculate, incubate, and count. No tubes, Science Suppliers and Programs dishes, media are needed. For middle level www.nsta.org/ads/supp-prog.asp and high school. A host of science and environmental education TO ORDER: Contact Flinn Scientific, Inc., resources for teachers from the National Carolina Biological Supply Company, or Science Teachers Association. Items include Connecticut Valley Biological Supply Company science kits, curricula, equipment, books, (the companies are listed in this section) for videos, and more. Visit their Web site for a product, price, and order information. description of the materials and order Ward’s Natural Science information. The site also includes many www.wardsci.com suppliers. Here are a few of them: To request a free catalogue, you can call Carolina Biological Supply Company (800) 962-2660. In Canada, you can call www.carolina.com (800) 387-7822. International customers can To request a free catalogue, you can call call (716) 359-2502. (Shipping and handling (800) 334-5551. Or, mail a request to Carolina charges do not apply.) Materials are for Biological Supply Company, Mailing List high school biology and life science Dept., 2700 York Rd., Burlington, NC 27215. classes, grades 5 through 9. (Shipping and handling charges do not apply.) Catalogue requests may also be faxed to 1-800- 222-7112. Materials are for grades K and up. Connecticut Valley Biological Supply www.ctvalleybio.com To request a free catalogue, write to For online resources, check out Connecticut Valley Biological Supply Co., Inc., www.foodsafety.gov/~fsg/teach.html 82 Valley Rd., P.O. Box 326, Southampton, MA 01073. Or call (800) 628-7748. (Shipping and handling charges do not apply.) Materials are for grades 3 and up.
86 FOOD SAFETY SCIENCE AND OUR FOOD SUPPLY WAS BROUGHT TO YOU BY . . .
FOOD AND DRUG ADMINISTRATION NATIONAL SCIENCE TEACHERS ASSOCIATION CENTER FOR FOOD SAFETY AND APPLIED NUTRITION Arlington, VA Washington, DC
Marjorie L. Davidson, Ph.D. Wendell Mohling, Ph.D. Cynthia Holland Education Team Leader, Food Safety Initiative Associate Executive Director Newberry High School Conventions and Professional Programs Newberry, FL Louise H. Dickerson FDA/NSTA Science and Our Food Supply Science and Our Food Supply Project Director Program Director Millie Linares 2004 to present John B. Connally Middle School Christina Gorski San Antonio, TX Laura A. Fox FDA/NSTA Science and Our Food Supply Science and Our Food Supply Project Director Program Manager Douglas Mandt 1999 – 2004 Science Education Consultant Jill Heywood Art J. Miller, Ph.D. FDA/NSTA Science and Our Food Supply Joseph Moore Coordinator of the Scientific Review Program Assistant William Robinson Center Augusta, GA FDA Scientific Reviewers NSTA Expert Panel Ellajay Parfit Elisa L. Elliot, Ph.D. Ken Bingman, Lead High School Advisor Southeast Middle School Peter Feng, Ph.D. Baltimore, MD Kathy Gombas Shawnee Mission West School Jack Guzewich Shawnee Mission, KS Nancy Ridenour Farukh M. Khambaty, Ph.D. Ithaca City School Miriam Cooper, Lead Middle Level Glenda R. Lewis Ithaca, NY Advisor Sherri A. McGarry Higgins Middle School Robert I. Merker, Ph.D. Claudine Stansbury Peabody, MA John P. Sanders, Jr., Ph.D. Sheffield High School Memphis, TN Michelle A. Smith, Ph.D. Pamela Taylor Henson Ben D. Tall, Ph.D. Baldwin County Schools Mark O. Walderhaug, Ph.D. Loxley, AL
THANK YOU TO THE FOLLOWING CONTRIBUTORS . . .
FOOD AND DRUG ADMINISTRATION THE NATIONAL CENTER FOR U.S. FOODSERVICE EDUCATIONAL CONTRIBUTORS OFFICE OF REGULATORY AFFAIRS FOOD SAFETY AND TECHNOLOGY Rosemont, IL Tracy Ajello NORTHEAST REGIONAL LABORATORY ILLINOIS INSTITUTE OF TECHNOLOGY Jorge Hernandez Doolittle School Jamaica, NY MOFFETT CAMPUS Chesire, CT Summit-Argo, IL BEEF MAGAZINE Alice Cohen Minneapolis, MN Amanda Janis Susan Jackson Kathy Knutson, Ph.D. Gettysburg College Jose Moreno Charles Sizer, Ph.D. Joe Roybal Gettysburg, PA Barbara Paul, Ph.D. U.S. DEPARTMENT OF AGRICULTURE UNIVERSITY OF MARYLAND Laura Schankweiler Brian Murfin, Ph.D. AGRICULTURAL RESEARCH CENTER College Park, MD Marilyn Smith, Ph.D. New York University Beltsville, MD Ann Smith, Ph.D. New York, NY FOOD AND DRUG Bradford Berry, Ph.D. ADMINISTRATION SUFFOLK COUNTY DEPARTMENT John Kucharski CENTER FOR BIOLOGICS OF HEALTH SERVICES Patricia Millner, Ph.D. EVALUATION Hauppauge, NY Morse Solomon, Ph.D. AND RESEARCH Bruce Williamson Bethesda, MD FLOW INTERNATIONAL CORPORATION Ernst Dinda Kent, WA Lan Hu, Ph.D. Dennis J. Kopecko, Ph.D. Ken Mundt Edmund Y. Ting, Sc.D. CENTERS FOR DISEASE CONTROL AND PREVENTION MS BIOSCIENCE, INC. Atlanta, GA Dundee, IL Arthur P. Liang, M.D. Elizabeth Dunlap, Ph.D. Julia Smith
FDA and NSTA would especially like to thank all of the middle and high school teachers who have participated in the FDA/NSTA Professional Development Program in Food Science, as well as thank Isabelle L. Howes at the Graduate School, USDA, for her role in administering the program.
FOOD SAFETY 87 Center for Food Safety and Applied Nutrition www.foodsafety.gov/~fsg/teach.html 2007