Microbiological hazards and safe process design M.H. Brown, Unilever Research, Sharnbrook 11.1 Introduction Many different ingredients and raw materials are processed to make chilled foods. At harvest or slaughter these materials may have a wide range of microbes in or on them. Some of them carry the micro-organisms that cause their eventual spoilage(e.g. bacilli or Lactic acid bacteria) whilst others pick them up during harvesting or processing. Many food poisoning bacteria occur naturally with farm animals and agricultural produce(e.g. Salmonella, E coli o157 and Campylobacter)and hence can contaminate meat and poultry, milk and vegetable products. The numbers and types present will vary from one ingredient to another and often product safety at the point of consumption will depend on manufacturing, consumer use and the presence or numbers of thogens in the raw material and eventually in the manufactured product. In order to ensure safe products with a reliable shelf-life, the manufacturer must identify which food poisoning and spoilage bacteria are likely to be associated with particular raw materials and products(e.g. by microbiological surveys) Therefore it is essential to design food processing procedures according to principles that ensure that the hazard of food poisoning is controlled. Thi especially important in the prepared foods and cook-chill sectors where safety relies on the control of many features of the manufacturing process (ICMSF 1988, Kennedy 1997). The appropriate means of control should be incorporated into the product and process design and implemented in the manufacturing operation. Often the means of control exist at several stages along the supply chain. For example Gill et al.(1997) have suggested that the overall hygienic quality of beef hamburger patties could be improved only if hygienic quality beef (i.e. lowest possible levels of contamination with pathogens) was used for11.1 Introduction Many different ingredients and raw materials are processed to make chilled foods. At harvest or slaughter these materials may have a wide range of microbes in or on them. Some of them carry the micro-organisms that cause their eventual spoilage (e.g. bacilli or Lactic acid bacteria) whilst others pick them up during harvesting or processing. Many food poisoning bacteria occur naturally with farm animals and agricultural produce (e.g. Salmonella, E.coli O157 and Campylobacter) and hence can contaminate meat and poultry, milk and vegetable products. The numbers and types present will vary from one ingredient to another and often product safety at the point of consumption will depend on manufacturing, consumer use and the presence or numbers of pathogens in the raw material and eventually in the manufactured product. In order to ensure safe products with a reliable shelf-life, the manufacturer must identify which food poisoning and spoilage bacteria are likely to be associated with particular raw materials and products (e.g. by microbiological surveys). Therefore it is essential to design food processing procedures according to principles that ensure that the hazard of food poisoning is controlled. This is especially important in the prepared foods and cook-chill sectors where safety relies on the control of many features of the manufacturing process (ICMSF 1988, Kennedy 1997). The appropriate means of control should be incorporated into the product and process design and implemented in the manufacturing operation. Often the means of control exist at several stages along the supply chain. For example Gill et al. (1997) have suggested that the overall hygienic quality of beef hamburger patties could be improved only if hygienic quality beef (i.e. lowest possible levels of contamination with pathogens) was used for 11 Microbiological hazards and safe process design M. H. Brown, Unilever Research, Sharnbrook