26/11/2014 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 HdlHurdle CtConcept • Basic Aspects • Application of Hurdle Technology • Design of Hurdle Technology Foods SEAFAST Center IPB Lilis Nuraida, Desember 2010 1 26/11/2014 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 2 26/11/2014 PRINCIPLES OF HURDLE CONCEPT SEAFAST Center IPB Lilis Nuraida, Desember 2010 3 26/11/2014 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 4 26/11/2014 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 SEAFAST Center IPB Lilis Nuraida, Desember 2010 5 26/11/2014 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) SEAFAST Center IPB Lilis Nuraida, Desember 2010 6 26/11/2014 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 7 26/11/2014 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 SEAFAST Center IPB Lilis Nuraida, Desember 2010 8 26/11/2014 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 9 26/11/2014 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 10 26/11/2014 APPLICATION OF HURDLE TECHNOLOGY SEAFAST Center IPB Lilis Nuraida, Desember 2010 Application of Hurdle Technology • Industrialised countries: – Minimally process food: HMF (High Moisture Food) • Chilled or forzen • Additiona l hdlhurdles: 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 11 26/11/2014 Hurdle technology Has been used unintentionally Pickles pH + preservative (acid) + salt Sausage aw + smoke + salt + spices + preservatives