Food safety and Microbial standards, Food quality standards
Food safety-Indicators of food microbial Quality and safety-Coliforms, Enterococci, Bifidobacteria, Coliphages/Enteroviruses, predictive Microbiology/ Microbial modeling
Microbial Standards of Processed and preserved Foods
The Center for disease control (CDC) investigates each documented outbreak of food borne disease and attempts to determine not only the specific microorganisms and foods involved but also the events which led to the outbreak.
Indicators of Food Safety:
Microbial indicators are employed more often to assess food safety and sanitation than quality. Ideally a food safety indicator should meet certain important criteria.
- It should be easily and rapidly detectable
- It should be easily distinguishable from other members of the food biota.
- It should have a history of constant association with the pathogen whose presence it is to indicate
- It should always be present when the pathogen of concern is present
- It should be an organism whose numbers ideally should correlate with those of the pathogen of concern.
- It should possesses growth requirements and a growth rate equaling or exceeding that of the pathogen
- It should have a die-off rate at least it parallels that of the pathogen and ideally persists slightly longer than pathogen of concern.
- It should be absent from foods that are free of the pathogen except perhaps at certain minimum numbers.
HACCP (Hazard Analysis Critical Control Point) System
- HACCP is a system that should lead to the production of microbiologically safe foods by analyzing for the hazards of raw materials-those that may appear throughout processing and those that may occur from consumer abuse.
- It is a proactive, systematic approach to controlling food bome hazards.
- Although some classic approaches to food safety rely heavily on end product testing, the HACCP system places emphasis on the quality of all ingredients and all process steps on the premise that safe products will result if these are properly controlled.
- The system is thus designed to control organisms at the point of production and preparation.
HACCP principles:
Although interpreted variously, the ICMSF and NACMCF view HACCP as a natural and systematic approach to food safety and as consisting of the following seven principles:
- Assess the hazards and risks associated with the growing, harvesting, raw materials, ingredients, processing, manufacturing, distribution, marketing, preparation, and consumption of the food in question.
- Determine the CCP(s) required controlling the identified hazards.
- Establish the critical limits that must be met at each identified CCP.
- Establish procedures to monitor the CCP(s).
- Establish corrective actions to be taken when there is a deviation identified by monitoring a given CCP.
- Establish procedures for verification that the HACCP system is working correctly.
- Establish effective record-keeping systems that document the HACCP plan.
Coli forms:
- Etiologic agent of cholera in 1885.
- Originally named as bacterium coli concerne because it was present in the stools of each patient he examined.
- Schardinger – suggested the use of this organism as an index of fecal pollution. Rapidly than individual water borne pathogens.
- A test for this organism as a measure of drinking water portability was suggested in 1895 by T. Smith.
- They produce metallic sheen on calories embager coliforms, citro bacter, Enterobacter, klebsicela, Raoultella.
- IMVIC formula is the classic method used.
(I = Indole Production; M = Methyl red reaction; V = Voges – Proskauer reaction; C = Citrate utilization)
Coliphages / Enterovinuses:
- Indirect indicators.
- A coli phage assay procedure for water samples that contain five or more phases / 100ml and that can be completed in 4-6 hours is described in “Standard methods for the examination of water and waste water”
Bifidobacteria:
Tissier (1908) identified and named as Bacillus bifidus. Later it was named as Lacto bacillus bifidus and contently known as Bifidobacterium bifidum.
- Commonly present in stools
- They are gram positive anaerobic bacteria as indicators of fecal pollution, especially of waters.
- Some bifido bacteria are employed in the production of fermented milks, yogurt and other food products and they are belived to provide some health benefits.
- Growth conditions – Temperature min 25-28°C and max 43-45°C and PH 5-8
- Produce lactic and acetic acids as the major end products of their carbohydrate metabolism
Distribution:
- Found in human feces at higher lutes per gram (108 – 109 ) than E. coli (106 – 107 ) and this makes them more attractive as indicators of human fecal pollution.
- By using the bifide bacteria, it is possible to determine their origin among the following three sources: human feces, animal feces or environmental conditions.
- Gavinietal (1991) devised the method to distinguish between human and animal strains and it devides bifido bacteria into suten groups.
- Human origin belong to I, III and VII.
- B. adolescentis and B. longum are mount often isolated in highest numbers.
Coliform criteria and standards:
- Grade A pasteurized milk & milk products including cultured products not over 10/ml
- Certified raw milk not more 10/ml. Certified pasteurized milk not over 1/ml
- Pre cooked & partially cooked frozen foods not over 10/ml
- Crab meat not over 100/ml
- Custard filled items not over 100/ml
IEMSF – International commission on the microbiological specifications for foods
Enterococci:
E. Faecalis (M. ovalis)
- Pollution indicators for water: