Foodsafetyandcheese食品安全和奶酪ppt课件

1、Food safety and cheeseInternational Food Safety ConsultancyDr.W.R. Marsman1;.2Raw milk- summarylIt is impossible to ensure that raw milk is free from pathogenic micro-organismslThat subsequent hygiene measures will not remove pathogens already presentlThat majority of cheese borne outbreaks have bee

2、n associated with raw milk cheese3continuelFollowing measures are important:lRaw milk should be collected and maintained in good hygiene conditionlIf raw milk is not used immediately it should be refrigerated lFor those product where a risk assessment indicates a hazard from pathogens in raw milk ,t

3、he milk should undergo a full pasteurization or equivalent process1.Good conditions of hygiene should be maintained through cheese production ,ripening ,distribution ,sale and storage until consumption to prevent contamination4continuelThe safety of cheese may be compromised by post pasteurization c

4、ontamination but that ,except in the case of low risk cheeses such as Parmesan, the total health risk to the consumer is less from cheese made from properly pasteurized milk than from cheese of similar composition made from unpasteurized milk5BackgroundlCheese was originally developed as a mean of p

5、reserving raw milk in times of excess productionlWas generally considered to be relatively safe food however the spread of some diseases have been demonstrated which resulted that most cheeses are now produced from milk that has been pasteurised6continuelCheese manufactured by traditional processes

6、may be made from raw milk whilst some larger scale operations may use thermised milk (less severe than pasteurization of 71.7 Celsius for 15 seconds)lSome pathogenic bacteria as Listeria Monocytogenes ,Salmonella and E. coli0157 may survived7Microbiological safety of cheeselThe compositional charact

7、eristics of the soft, mould ripened cheeses (e.g. Brie) are very different from those of the very hard, acid types (e.g. Parmesan) PH and water activities differ so it cannot be assumed that all pathogenic micro organisms will die out in all types of cheeselPathogenic bacteria vary just as widely as

8、 the cheeses they contaminate and their survival characteristics are equally variedlThe manufacture of cheese is complex8continuelThe manufacture of safe cheese demands the application of systems base on HACCP principles and must be applied at all points in the process from the rearing of milk produ

9、cing animals to cheese consumption by the consumerlIn addition to potential faecal contamination pathogens may also be excreted into milk directly from udder.lCorrectly controlled milk pasteurization kills such bacteria lA farm to fork approach employing HACCP base systems is widely advocated to control pathogens in food production9continuelMicrobiological tests on finished cheese are useful for monitoring the success