Fermentation
Gabrielle Allen - Senior Food Science Officer Food Safety Unit - Department of Health and Human Services, Victoria Today’s topics
What is fermentation
What is fermented
Where do we find fermented foods
Food safety of fermented food and drink Pub quiz
SCOBY Pub quiz
Oenophobia The return of tradition
http://www.penn.museum/blog/collection/125th-anniversary-object-of-the-day/7000-year-old-wine-jar-object-of-the-day-24/ Foodborne illness incidence
Food Country Year Sick Deaths Pathogen Cause
Home pickled turshi (middle US 2013 4 0 C. botulinum Unsatisfactory fermentation eastern fermented vegetables)
Pruno (prison alcohol) US 2011 8 0 C. botulinum Untested recipe. Potato added increasing pH allowing C. botulinum to grow.
Pruno US 2016 26 C. botulinum
Tofu US C. botulinum bulk tofu which had been kept unrefrigerated, uncovered, and in water- filled bins Home-canned pickled vegetables US 2016 1 C. botulinum
Seal flipper US 2015 4
Beaver tail US 2016 1 C. botulinum
Fermented blackbeans (douchi) China 2014 139 0 B. cereus Unsatisfactory fermentation
Kimchi – raddish and cabbage Korea 2012 1642 0 E. coli 0169 variants Hazelnut yoghurt UK 1989 27 1 C. botulinum Contaminated hazelnut conserve
Salami and metwurst AUS 1995 150 + 1 E. coli and Traceability, back sloping etc etc Salmonella Source: Barblog Foodborne illness incidence
Food Country Year Sick Death Pathogen Cause s
Fresh garlic in oil US 36 0 C. botulinum Unsatisfactory acidification, anaerobic conditions
Olives Italy 2016 Unknown 1 C. botulinum
Semi dried tomatoes AUS 2009 140 Hepatitis a processing expired tomatoes
Fermented seal flipper US (Alaska) 3 0 C. botulinum Change of process, creating anaerobic conditions
Home pickled tomatoes Azerbaijan 2015 8 1 C. botulinum Unsatisfactory fermentation
Home preserved mushrooms in oil Italy 1998 1 1 C. botulinum Unsatisfactory acidification, anaerobic conditions
Olives Finland 2011 2 0 C. botulinum Process failure
Source: Barblog What has changed?
So if the principles and processes are the same, and there are few instances of foodborne illness, why are we worried about food safety?
• supply chain
• wider distribution
• industrialisation Skinned seal flippers ready to be fermented. Note the plastic rubbish bin bag. Image: NativeTech. • consumer expectation, in regards to rigorous food safety systems
• increase of cottage industries in recent years – Masterchefitis
• breakdown in the generation to generation knowledge exchange, loss of knowledge
• changes to traditional processes
• changes to traditional recipes
A manufacturer of wine… Activity 1: Changes in traditional processes Botulism from fermented seal flipper…
Skinned seal flippers ready to be fermented Image: NativeTech. Activity 2: Changes in traditional recipes
Botulism from drinking pruno (otherwise known as prison wine, jailhouse hooch, juice, or brew)…
A manufacturer of wine… Image barfflog Why do we ferment food?
• flavour development
• nutritive value
• preservation (pH control for food safety) What is fermentation?
Fermented food and beverages undergo a microbial process, where yeasts, bacteria or moulds degrade or break them down into by-products. What is fermentation?
Sugar becomes food acid
(yoghurt, sauerkraut/kimchi, kombucha)
Sugar becomes alcohol Alcohol becomes food acid
and acid (beer, wine) (vinegar) Different types of fermentations
Source: Fermentation and food safety. Martin R Adams, MJ Robert Nout Activity 3 - Back to school The products – the diversity of fermentation
The products – the diversity of fermentation
Worldwide: alcohol, wine, vinegar, olives, yogurt, bread, cheese
Asia
• East and Southeast Asia: amazake, atchara, bai-ming, belacan, burong mangga, com ruou, dalok, doenjang, douchi, jeruk, lambanog, kimchi, kombucha, leppet-so, narezushi,miang, miso, nata de coco, nata de pina, natto, naw-mai-dong, oncom, pak-siam-dong, paw-tsaynob, prahok, ruou nep, sake, seokbakji, soju, soy sauce, stinky tofu, szechwan cabbage, tai-tan tsoi, chiraki, tape, tempeh, totkal kimchi, yen tsai, zha cai
• Central Asia: kumis (mare milk), kefir, shubat (camel milk)
• South Asia: achar, appam, dosa, dhokla, dahi (yogurt), idli, kaanji, mixed pickle, ngari, hawaichaar, jaand (rice beer), sinki, tongba, paneer
Africa: fermented millet porridge, garri, hibiscus seed, hot pepper sauce, injera, lamoun makbouss, laxoox, mauoloh, msir, mslalla, oilseed, ogi, ogili, ogiri, iru
Americas: sourdough bread, cultured milk, chicha, elderberry wine, kombucha, pickling (pickled vegetables), sauerkraut, lupin seed, oilseed, chocolate, vanilla, tabasco, tibicos, pulque, mikyuk (fermented bowhead whale)
Middle East: kushuk, lamoun makbouss, mekhalel, torshi, boza
Europe: rakfisk, sauerkraut, pickled cucumber, surströmming, mead, elderberry wine, salami, sucuk, prosciutto, cultured milk products such as quark, kefir, filmjölk, crème fraîche,smetana, skyr, rakı, tupí.
Oceania: poi, kaanga pirau (rotten corn), sago What about pickles? Quiz question one – How do acids act as preservatives?
1. By cooking the food
2. By stopping or slowing the growth of food poisoning and spoilage bacteria
3. By providing anaerobic conditions
4. By making the food taste nice
Answer - Food acids act as preservatives by reducing the food’s pH and thus stopping or slowing the growth of many food poisoning and spoilage bacteria. Quiz question three – Which food poisoning bacteria is the most significant concern for acidified foods? 1. Escherichia coli 2. Clostridium botulinum 3. Bacillus cereus 4. Salmonella
Answer - Clostridium botulinum Quiz question two – What pH limits the growth of Clostridium botulinum?
1. 7.01 2. 4.6 3. 10.3 4. 4.2
Answer - The risk of Clostridium botulinum spores germinating and producing toxins is increased if the pH is above pH 4.6. pH can rise as it equalises with the product, a stating pH of 4.2 is recommended to account for this. Quiz question five – Are all food poisoning bacteria limited by pH 4.6?
1. Yes 2. No
Answer - Some microorganisms are more acid tolerant than others Bacterial pathogens of concern in acidified products – acid tolerance
Limits for Growth of Some Common Bacterial Pathogens
Source: Fermentation and food safety. Martin R Adams, MJ Robert Nout Food safety threats – not just microorganisms
Source: Fermentation and food safety. Martin R Adams, MJ Robert Nout Food acid alone is not enough for adequate food safety
Key barriers in preventing food borne diseases in many cases are:
• good manufacturing practices (GMP),
• a robust hazard analysis and control process food safety program and
• good hygiene practices (GHP) Food acid alone is not enough for adequate food safety - hurdles
Food safety in acidification and fermentation specifically relies on:
•good quality undamaged raw materials
•contamination prevention (before, during and after processing)
•well controlled fermentation processes Food safety steps and examples of suitable parameters
Good quality undamaged raw materials • trusted raw materials suppliers • removing dirt and bacteria from raw produce by washing produce in potable water, or removing contaminated outer leaves or skins • heat treatment, to eliminate competing bacteria prior to acidification, such as using pasteurised milk for making yoghurt Food safety steps and examples of suitable parameters
Contamination prevention • good hygiene practices (such as handwashing) • cleaning and sanitising procedures Food safety steps and examples of suitable parameters
Well controlled fermentation processes • use a proven recipe • accurately follow recipe each time • the correct fermentation temperature • refrigeration of finished product • heat treatment (where appropriate) of finished product • addition of other ingredients such as salt Food acid alone is not enough for adequate food safety - hurdles
Ingredients and processes that can be used in combination with acid are:
• salt and/or sugar
• preservatives (additives such as sorbic acid, benzoic acid)
• heat treatment
• refrigeration Some examples of the fermentation process
Sauerkraut
1. Preparation of raw materials
2. Core, trim and shred
Inoculate, if using Salt 1.0 to 3.5 (typically 2.25) % ww
3. Fermentation process Anaerobic Temp 18-22 ºC for 2-6 weeks
4. Pack Some examples of the fermentation process
Yoghurt Heat pasteurised milk to eliminate competitive flora and cool 30-32 ºC
Inoculate Fermentation process Temp 30-40 ºC for 6-20 hours
Cool
Pack and refrigerate Fermented soft drinks Some examples of the fermentation process
Kombucha Boil water and steep tea
Cool
Inoculate with starter culture (SCOBY - Fermentation process Sugar for symbiotic colony Temp 18 – 26 ºC for 10 – 14 of bacteria and yeast) days
Sweeten and flavour
Pack and refrigerate Spoilers…….
Proportion of drinks compliant with the Code – national survey Spoilers……. Multiple factors influence the alcohol content of brewed soft drink
These include:
• drink type
• shelf life
• secondary fermentation
• flavouring
• temperature
• measurement Group discussion
Where, in your role as an EHO, might you find products that have been fermented? Activity 4: Spot the ferment ` Bistro Blackwood – Rundle Street Adelaide The pot by Emma McCaskill - Hyde Park 94º West, Findon
The flying fig - North Adelaide
Assessing skills and knowledge Assessing skills and knowledge - the key points
How are they controlling pH?
Is the pH under 4.6?
How are they controlling alcohol? Activity 5 Assessing skills and knowledg - what questions should you ask your fermented food producer?
• Sauerkraut • Yoghurt • Kombucha Some examples of the fermentation process
Sauerkraut
Similar products – kimchi, dill pickles, cornichons
1. Preparation of raw materials
2. Core, trim and shred
Inoculate, if using Salt 1.0 to 3.5 (typically 2.25) % ww
3. Fermentation process Anaerobic Temp 18-22 ºC for 2-6 weeks
4. Pack Some examples of the fermentation process
Yoghurt Heat pasteurised milk to eliminate competitive flora and cool 30-32 ºC
Inoculate Fermentation process Temp 30-40 ºC for 6-20 hours
Cool
Pack and refrigerate Some examples of the fermentation process
Kombucha Boil water and steep tea
Cool
Sugar
Inoculate with starter Fermentation process culture (SCOBY - Temp 18 – 26 ºC for 10 – 14 for symbiotic colony days of bacteria and yeast)
Sweeten and flavour
Pack and refrigerate Key questions
How do you make your product?
What is the pH of your product?
How are you controlling the alcohol? Health claims
Health claims - note that these apply to both labels and advertisements
It is the businesses responsibility to make sure health claims are compliant with the approved conditions in Schedule 3 of Standard 1.2.7 Nutrition, health and related claims, or meet the requirement of providing a body of evidence to substantiate general level health claims. pH measurement and meter calibration pH and acidity pH is the strength of an acid in the sample
Acidity is the amount of acid in a sample, or the amount of base required to neutralize a sample. Methods to measure pH
Litmus paper
Advantages
1. no calibration
2. inexpensive
3. simple
Disadvantages
1. sample colour interference
2. precision
3. accuracy Methods to measure pH continued
pH meter - meter with electrode
Advantages
• precision
• diversity of design and application
• accuracy
• $ to $$$
Disadvantages
• calibration
• complexity
• cleaning and storage pH meters. What should EHOs look for?
• calibration solutions • cleaning solutions • storage solutions
How often do you calibrate your meter? Are they in date? When were they opened? Is the probe cleaned regularly? How is the probe stored? Measurement technique
• rinse between samples with water
• fully immerse Junction
• stir the sample
• wait for stabilisation
• consistent sample temperature Measurement method
Sample slurry Direct measurement Liquid and solids Key points for accurate readings
• calibration
• measurement technique
• cleaning routine
• storage routine