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chp10 - Microbiological Criteria FScN 4131 Food Quality...

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Unformatted text preview: Microbiological Criteria FScN 4131 Food Quality October 23, 2000 Acknowledgments F.F. Busta FScN 5122 Control Systems in Food Microbiology Spring, 1999 Principles for Establishment of Microbiological Food Safety Objectives and Criteria Definitions ❚ ❚ ❚ ❚ ❚ Criteria Food safety objective Performance criterion Process criterion Default value ❚ Provide guidance ❚ Establishment of food safety objectives to assure the safety of food Definitions ❚ Criteria ❙ A standard, specification, guideline Definitions ❚ Food safety objective ❙ a statement of the frequency or maximum concentration of a microbiological hazard in a food considered acceptable for consumer protection ❚ ❚ ❚ ❚ Food safety objective Performance criterion Process criterion Default value ❚ Performance criterion ❚ Process criterion ❚ Default value Definitions ❚ Food safety objective ❚ Performance criterion ❙ the required outcome of a step or combination of steps which will assure a food safety objective is met Definitions ❚ Food safety objective ❚ Performance criterion ❚ Process criterion ❙ the control parameters of a step or combination of steps that can be applied to achieve the performance criterion ❚ Process criterion ❚ Default value ❚ Default value Definitions ❚ ❚ ❚ ❚ Food safety objective Performance criterion Process criterion Default value ❙ a conservative criterion established to assure the safety of a food under worst-case conditions Food Safety Objectives ❚ The primary function of an FSO is to communicate the level of control that is necessary to achieve an acceptable level of protection. ❚ Four components: ❙ ❙ ❙ ❙ hazard of concern type of food acceptable level of risk acceptable level of protection Key to Control of Microbes ❚ management of numbers ❙ microbial ecology-relationship between organisms and their environment, resulting in growth, survival, or death ❙ environment = abiotic (physical/chemical) and biotic (other microbes & host) Control Measures ❚ Five Basic Activities: ❙ Avoiding foods with a history of contamination or toxicity ❙ Selecting ingredients ❙ Preventing contamination ❙ Destroying pathogens ❙ Preventing growth of pathogens Performance Criterion Performance Criterion ❚ ΣR + ΣG < FSO - Ho ❚ where: ❙ ΣR = cumulative total reduction effect during processing ❙ ΣG = the cumulative total growth increase of the hazard ❙ FSO = Food safety objective ❙ Ho = initial level of hazard ❙ H, R, and G are expressed in log10 units ❙ R is negative by definition (reduction) ❚ Required outcome of one or more control measures at a step or combination of steps which will assure the safety of the food Process Criteria ❚ Control parameters (e.g. time, temperature, pH, aw) at a step or combination of steps that can be applied to achieve a performance criterion. ❚ ❚ ❚ ❚ Factors to Consider Pathogens to be controlled The food Conditions of processing distribution, storage, and preparation procedures for serving ❚ All relevant sources of information Process Criteria Validation of Process Criteria ❚ Maximum intrinsic resistance of the pathogen ❚ Composition of the food ❚ Process variability ❚ Storage, distribution, preparation for use ❚ Process criteria will commonly appear as critical limits for critical control points in HACCP plans Microbiological Criteria Uses I ❚ Safety of food ❚ Adherence to good manufacturing processes ❚ Keeping quality of certain perishable foods ❚ Utility (suitability) of a food or ingredient for a particular purpose Microbiological Criteria Uses II ❚ When appropriately applied, can be a useful means for ensuring safety and quality of foods, which in turn, elevates consumer confidence ❚ Provide the food industry and regulatory agencies with guidelines for control of food processing systems ❚ Internationally accepted criteria can advance free trade through standardization of food safety and quality requirements Who Establishes Criteria? ❚ Joint Food & Agricultural Organization and World Health Organization ❚ Codex Alimentarius-WTO ❚ International Committee for Microbiological Specification of Foods ❚ National Academy of Sciences ❚ National Advisory Committee on Microbiological Criteria for Foods Establishing Need for Micro Criteria I ❚ evidence of hazard to health ❚ nature of natural or acquired microflora and ability of food to support growth ❚ effect of processing on food microflora ❚ potential for contamination and/or growth during processing, storage, distribution Establishing Need for Micro Criteria-II Establishing Need for Micro Criteria-III ❚ ❚ ❚ ❚ category of consumers at risk state in which food distributed potential for abuse at consumer level spoilage potential, utilities, and GMPs ❚ manner in which the food is prepared for ultimate consumption ❚ reliability of methods available to detect and/or quantify microbes and toxins of concern ❚ costs and benefits of application of criteria Components Components of Microbiological Criteria for Foods Why Indicator Microorganisms? ❚ Tests may be used to assess either microbiological quality or safety when a relationship between the occurrence of the indicator organism and the likely presence of a pathogen or toxin has been established ❚ Level of spoilage organisms may reflect the microbiological quality, or wholesomeness, of a food product, as well as the effectiveness of measures used to control or destroy such microorganisms ❚ statement of the microorganisms of concern and/or their toxins/metabolites and the reason for that concern ❚ analytical methods for their detection/quantification ❚ plan defining the number of field samples to be taken and the size of the analytical unit ❚ microbiological limits considered appropriate to the food at the specified point(s) of the food chain ❚ number of analytical units that should conform to these limits Ideal Indicator Microorganisms I ❚ present and detectable in all foods whose quality is assessed ❚ growth and numbers should have direct and negative correlation with quality ❚ easily detected and enumerated and clearly distinguishable from other organisms Ideal Indicator Microorganisms II ❚ enumerable in short period of time ❚ growth should not be affected adversely by other components of food or other microorganisms ❚ history of relationship to quality parameter under test Fecal Contamination Indicator Organisms I Fecal Contamination Indicator Organisms II ❚ easily and rapidly detectable ❚ easily distinguishable from other food organisms ❚ history of association with pathogen that they indicate ❚ always be present when pathogen present ❚ numbers should ideally correlate with pathogen(s) ❚ possess growth requirements and rate same as pathogen ❚ die-off rate that parallels that of pathogen ❚ absent from foods free of pathogen Fecal Contamination Indicator Organisms III Fecal Common Fecal Indicators ❚ E. coli for fecal contaminationfor presence implies risk of other “enteric” pathogens ❚ fecal coliforms ❚ Enterococci ❚ ideally indicator should occur only in intestine ❚ should occur in high numbers in feces ❚ should possess high resistance to environment ❚ detectable at low levels Zero Tolerance for Pathogens ❚ ❚ ❚ Salmonella E. coli 0157:H7 0157:H7 Listeria monocytogenes Pathogens ❚ Can pathogens be used as indicators? ❚ Can indicators ever be absolutely ruled out as pathogens? ...
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