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Food Safety: Hot Issues, Jakarta 9 Desember 2010
HURDLE CONCEPT FOR MANAGING FOOD SAFETY
LILIS NURAIDA SEAFAST Center and Department of Food Science and Tecnology Bogor Agricultural University
Outline • Introduction • PiPrinc ip les of HHdlurdle CCtoncept • Basic Aspects • Application of Hurdle Technology • Design of Hurdle Technology Foods
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INTRODUCTION: Food Preservation
Food preservation aims to • Inhibition control all the forms of losses, • Inactivation with the priority to minimize the occurence and the growth • Avoid contamination of microorganism particularly (or re‐contamination) those caused food poisoning
Critical values of these parameters: Death, Survival or Growth microorganism are the basis of food preservation
SEAFAST Center IPB Lilis Nuraida, Desember 2010
INTRODUCTION: Consumer vs Food Industry Trends in consumer requirements Food industry reactions • Improve convenience • Milder processing • Use nonthermal alternative to • Higher quality heat • Fresher • Fewer additive • Use of hurdle technology or • More natural combination of preservation system • Nutritionally healthier • Use more natural antimicrobial • Minimally packaged system • Less use of salt, saturated fats, • Safer sugar, more low‐calorie food • Environmental friendly packaging • Elimination of food poisoning microrganism
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PRINCIPLES OF HURDLE CONCEPT
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Hurdle Effect
• Fundamental of food preservation: – Controling microbial spoilage – Controling Food poisoning – Controling Fermentation processes • Hurdles must keep the normal population of microoganism in food under control.
The microorganism at start in a food should not be able to overcome the hurdles present; otherwise the food will become spoilSEAFAST or even Center cause IPB food poisoning Lilis Nuraida, Desember 2010
Hurdle Technology • Food preservation by combined methods • Combined processes • Combination preservation • Combination techniques
• Developed for limiting the growth of microorganisms in nonsterile foods (Leistner, 1978) • Combined effects of preservation methods > sum of effects individually or large amounts of a single factor SEAFAST Center IPB Lilis Nuraida, Desember 2010
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Potential Hurdles for Foods • Temperature (low or high) • pH • Aw • Eh • Modified Atmosphere (N2, CO2, O2) • Packaging (acseptic packaging, vacuum, MAP, active packaging, edible coating) • Pressure (high) • Radiation (microwave, UV and irradiation) • Other physical processes (mano‐thermo sonication, high electric field pulses, oscillating magnetic field pulse) • Microstructures (emuslion, fermented sausages, ripened cheese) • Preservatives SEAFAST Center IPB Lilis Nuraida, Desember 2010
Possible Effect of Combination Preservation Methods
• Simultant: additive or synergistic – Low Eh increases the in hibition by low aw • Heat resistance of bacteria decrease in the presence of preservatives • But increase at low aw
• Mildly heated canned foods need refrigeration during storage • Fermented sausages only stable and safe if both aw and pH are in appropriate range
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all hurdles at the same intensity all hurdles at different intensity low initial microbial load good hygienic practice high initial microbial load
F : heating; t : chilling; aw; pH : acidity; Eh : redox potential; pres : chemical preservative (Leistner, 1992) SEAFAST Center IPB Lilis Nuraida, Desember 2010
low initial microbial load more nutrients substerilizing treatment damaged cells
Sequence of hurdle in fermented sausages
F : heating; t : chilling; aw; pH : acidity; Eh : redox potential; pres : chemical preservative; V: vitamins, N: Nutriens; K‐F: competitive flora
(Leistner, 1992)
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Possible synergistic of hurdle, relate to multitarget disturbance of homestatis: the intelligent combination of different hurdles.
SEAFAST Center IPB Lilis Nuraida, Desember 2010
Hurdle Technology vs Total Quality • Possible hurdles in foods might influence the safety and stability, as well as sensory, nutrititive, technological and economic properties • Distinguishing between positive and negative hurdles for the quality of foods
• Chilling of fruit: unsuitably low temperature will be detrimental to fruit quality, while moderate chilling is beneficial • pH of fermented sausages: should be low enough to pathogenic bacteria, but not so low as to impare taste • Energy preservation: refrigetarion is replaced by aw, pH or Eh • Reduce preservatives: i.e. nitrite in meat is replaced by aw, pH, refrigeration or competitive flora SEAFAST Center IPB Lilis Nuraida, Desember 2010
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BASIC ASPECTS OF HURDLE CONCEPT: Homeostasis Metabolic exhaustion Stress reaction
SEAFAST Center IPB Lilis Nuraida, Desember 2010
Bacterial Stress Response Towards Hostile Treatments Various hurdles, such as heat treatment, low aw, low pH, salt , preservaives and low storage temperature are normally used to prevent the growth of undesirable bacteria in the food. Even so, some bacteria will survive these treatments and will grow with the aid of various defence mechanisms. The feasible responses of the microorganisms to such hostile environment determine wether they may grow or die
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Homeostasis
• The tendency toward uniformity or stability in the normal status (internal environment) of organism – Maintenance of a defined pH within narrow limits – Osmoregulation to counter balance a hostile aw • If the homeostasis of microorganism is disturbed by hurdles factors, they will not multiply, i.e. remain in lag phase even die, before their homestasis is re‐established (repaired) • The repair of a disturbed homeostasis demands much energy – Restriction of energy supply inhibits repair mechanism, i.e. Vacuum or MAP (Modified Atmosphere Packaging) – Lead to synergistic effect of hurdles factors • i.e. Low aw, low pH and Eh
SEAFAST Center IPB Lilis Nuraida, Desember 2010
Metabolic exhaustion
• Lead to autostrelisation – Mildly heated (95oC) liver sausages with adjusted aw by additon salt and fat: some Microorganism in stable spores survive and germinate under less hurdle technology foods favorable conditions for growthgerminated will try every possible spores die mechanis to for their – High Moisture Fruit Products: survival homeostasis to overcome microoganism after mild heating decreased the hostile environment fast in the product during unrefrigerated storage due to addtional hurdles applied (pH, aw, sorbate and sulfite) Completely use up their • Vegetative microorganism will die more quickly if energy, and die the stability is close to treshold for growth, storage (metabolically exhausted) temperature is elevated, antimicrobial substances If more hurdles present, cause increasing energy are present, and the organism are sublethally demands to maintain injured homeostasis SEAFAST Center IPB Lilis Nuraida, Desember 2010
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Stress Reaction • Limitation to the success of hurdle technology • Some bacteria become more resistant or even more virulent under stress
• Heat, pH, aw, ethanol and starvation induce the synthesis of protective stress shock protein
Figure: www.science.uva.nl/sils/mbmfs/object.cfm/1FCDA076‐ • If different stresses are received at the same 1321‐B0BE‐6821F4FC1D66AFB3 time, the switch‐on of genes for the Listeria in Coleslow (Francis & O’Beirne, 2001) synthesis of shock proteins could become more difficult • More energy demands
Apply a multitarget preservation of foods SEAFAST Center IPB Lilis Nuraida, Desember 2010
Multitarget Preservation • The ultimate goal for a gentle but the most effective preservation • Different hurdles could not just have an additive effect, but may synegistically • If at the same time the hdlhurdles hit diferen t tttargets: cell membrane, DNA, enzyme system, pH, aw, and Eh within the microbial cells • The repair of homeostasis and the activation of stress shock protein become more difficult
• It is more effective to use different preservative (or preservation methods) than use only one preservative (or preservation method) in large amount • Example of multitarget process: application of nisin (damages the cell membrane) in combination with lysozyme and citrate that disturbe homeostasis Photo: www.nofima.no/mat/en/researcharea/bacterial‐ stress‐response • Preservation measure should be based on intelligent selection and combination of hurdle taken from different target classes SEAFAST Center IPB Lilis Nuraida, Desember 2010
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APPLICATION OF HURDLE TECHNOLOGY
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Application of Hurdle Technology • Industrialised countries: – Minimally process food: HMF (High Moisture Food) • Chilled or forzen • Additiona l hhdlurdles: htiheating, pH, aw, Eh, preservatives and competitive flora – Development of novel products – Optimization of traditional foods • Developing countries: – Stabilizes foods stored without refrigeration: IMF • Aw is ppyrimary hurdle • Additional hurdles: heating, preservatives, pH, Eh and competitive flora • General trends to move from IMF because they are often too salty or too sweet, and have a less appealing texture than HMF – Optimization of traditional foods SEAFAST Center IPB Lilis Nuraida, Desember 2010
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Hurdle technology
Has been used unintentionally
Pickles pH + preservative (acid) + salt Sausage
aw + smoke + salt + spices + preservatives IMF (dr ie d fitfruit, soft cookies )
aw + heating + preservatives
SEAFAST Center IPB Lilis Nuraida, Desember 2010
Meat Preservation
Important hurdles for meat preservation
High temperature: Heat treatment
Low temperature: Cooling, freezing
Water activity (aw): Drying, salt, sugar, fat Acidity (pH): Acidification
Redox potential: Decrease oxygen (vacuum, ascorbate)
Preservatives: Sorbate, nitrite etc.
Competitive flora: Fermentation (only applicable for non‐ heat‐treated products)
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Fermented Foods
In Fermented sausages, raw hams, ripened cheese and pickles, a sequences of hurdles leads to stable and safe products
Important hurdles in salami: • In the early stage nitrite and salt inhibit bacteria in the batter • Other bacteria are multiply and used up the oxygen, cause decrease ithe redox potential • Eh inhibits areobic organism and favors the selection of LAB (lactic acid bacteria) • LAB as competitive flora, metabolise sugar, decrease the pH • During ripening, nitrite depleted, Eh increase, LAB vanish, pH increase. Only aw responsible for the stability of long ripened raw sausages SEAFAST Center IPB Lilis Nuraida, Desember 2010
Shelf‐Stable Products (SSP)
• Heat‐processed high moisture food based on hurdle technology • Advantages: – Mild heat treatment (70‐1100C)improves the sensory and nutritional properties – Lack of refrigeration simplifies distribution and save energy during storage • Heated in sealed containers which avoid recontamination after processing • Because of the mild heat treatment the foods still contain viable bacterial spores: – Inhibited by an adjustment of aw, pH, Eh and sublethal injured of spore (in the case of autoclaved sausages)
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Different Shelf‐Stable Products and Their Primary Hurdles Type Hurdles Examples F‐SSP Sublethal damage Sausages with an adjusted aw (Bologna type sausages with of bacterial aw<0.97) in PVDC that are heated in counterpressure of
spores autoclave to F0 >0.4 Mechanism: metabolic exhaustion Aw‐SSP Slightly reduced Meat products: Italian mortadella and German water activity bruhdauerwurst (<0.95) The shelf life is better than fermented sausages pH‐SSP Slightly increased Gelderse rookworst, jelly sausages acidity pH adjustd by acetic acid (<4.8) Vegetative microorganism incativated by mild heating, and the spores are inhibited by acid Combi‐ Combination of Different type of bruhwurst and Italian pasta products SSP equal hurdles Hurdles: preservatives, aw, pH, vacuum packaging an re‐ pasteurisation All are mildly heated foods, stable at ambient temperature, but have fresh product characteristics (Leistner 2007) SEAFAST Center IPB Lilis Nuraida, Desember 2010
Thermally Processed Acidified Food pH F(Past) Eh
Gram positive bacteria Gram negative bibacteria Bacterial spore
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Chilled Food • If low temperature is the only hurdle, food safety easily breaks down in case of temperature abuse • Need additional hurdle as a back up and acting as safeguards in chilled foods – Invisible Technology
– Example MAP (2‐5% O2 and 5‐10% CO2) • Pathogens are not directly inhibited by CO2, but the competitive flora grow at reduced oxygen and increased CO2 might acts as hurdle to inhibit pathogens
SEAFAST Center IPB Lilis Nuraida, Desember 2010
Preservation of Fruits
Hurdles: water activity (aW), pH, preservatives (P), and slight heat treatment, T(t)
(A) an intermediate moisture fruit product;
(B) a high‐moisture fitfruit prodtduct;
(C) a minimally processed refrigerated fruit product.
www.fao.org/docrep/005/y4358e/y4358e06.htm SEAFAST Center IPB Lilis Nuraida, Desember 2010
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Biological control of postharvest diseases can be integrated with other methods with additive and synergistic effects, which also broadened the spectrum of activity (eradicative effect of heat, reduced decay by Ca) and further advanced the goal of eliminating fungicide treatments on fruits after harvest (Janisiewicz , 2007, www.ars.usda.gov/pandp/people/people.htm?personid=2774) SEAFAST Center IPB Lilis Nuraida, Desember 2010
Examples of Some Recent Development
• Antimicrobial effect and shelf‐life extension by combined thermal and pulsed electric field treatment of milk (Walkling‐ Ribeiro et al., 2008) • Combined effects of heat, nisin and acidification on the inactivation of Clostridium sporogenes spores in carrot‐ alginate particles: From kinetics to process validation ( Naim et al., 2008) • Shelf stable intermediate moisture pineapple (Ananas comosus) slices using hurdle technology (Sudhanshu et al., 2009) • PEF based hurdle strategy to control Pichia fermentans, Listeria innocua and Escherichia coli k12 in orange juice (C. McNamee, et al., 2010) SEAFAST Center IPB Lilis Nuraida, Desember 2010
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DESIGN OF HURDLE TECHNOLOGY FOODS
SEAFAST Center IPB Lilis Nuraida, Desember 2010
Risk to be considered
• In applying mild inactivation technology, incomplete inactivation and sub‐lethal damage of target microorganisms is often obtained
Hidden danger: • The growth prevented by application of • Incomplete germination sub‐optimal intrinsic and extrinsic factors and incomplete or futher inactivation inactivation of newly • Inactivation strategies for resistance spores vegettitative cells to mild heat: • Application of sub‐lethal • Induce germination, followed by stress factor could induce inactivate the newly formed resistance mechanism and vegetative cells their virulence characteristics SEAFAST Center IPB Lilis Nuraida, Desember 2010
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Points to be considered
• For designing food products, the concept of hurdle technology, predictive microbiology and HACCP should be applied • Hurdle technology should not lead to the addition too much additives but should actually reduce the amount of additives used, even their number might increase • Hurdles technology does not replaced sanitation and hygiene • Additional hurdles are introduced into a food product only after careful consideration of the necessity and in essential amount
SEAFAST Center IPB Lilis Nuraida, Desember 2010
10 Steps for Food Design Using an Integrated Concept: Hurdle, Predictive Microbiology and HACCP (Leistner 2007)
Establishing the Defining desired methods for Testing of microbial monitoring the properties and stability shlef‐lie process
Re‐challenging the product with Challenging the relevant product with food‐ Outlining feasible microoganisms technology poisoning and spoilage microorganisms Producing the food under industrial conditions Product analyses (pH, aw, Modifying the hurdles in the preservatives) Establishing CCPs product and monitoring procedures SEAFAST Center IPB Lilis Nuraida, Desember 2010
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THANK YOU TERIMA KASIH
SEAFAST Center IPB Lilis Nuraida, Desember 2010
10 Steps for Food Design Using an Integrated Concept: Hurdle, Predictive Microbiology and HACCP (Leistner 2007)
1. For the modified or novel food product, the desire sensory properties and desired shelf‐life are tentaively defined 2. A feasible technology for the production of this food has to be outlined 3. The food is manufactured according to this technology, and the resulting product is analyzed for pH, aw, preservatives or other inhibitory factors. Temperature for heating (if intended) and storage, as well as expected shelf life are defined 4. For preliminary microbial stability testing of the product, predictive microbiology might be employed 5. The product is challenged with food‐poisoning and spoilage microorganism, using somewhat higher innocula and storage temperature than would be normal for this food
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10 Steps for Food Design Using an Integrated Concept
6. If necessary, the hurdles in the product are modified, taking multitarget preservation and sensory quality of the food (i.e. total quality) into consideration 7. The food is again challenged with relevant microorganism, and if necessary the hurdles in the food are modified again. Predictive microbiology for assessing the safety of the food might be helpful at this stage too 8. After the established hurdles of modified or novel foods are exactly defined, including tolerance, the method for monitoring the process are agreed on. Preferably physical methods for monitoring should be used 9. The designed of food should now be produced under industrial conditions, because the possibilities for scalle up of the manufacturing process must be validated 10. For the industrial process, the CCP and their monitoring should be established, and therefore the manufacturing process should be controlled by HACCP. If HACCP is not appropriate, guidleines for the application of manufacturing control by GMP must be defined
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