Food Safety is essential to prevent outbreaks of foodborne illness such as Salmonella. Agronomic foods, such as meat, dairy, nuts, grain, seeds and spices are processed in an agricultural environment and are often contaminated with pathogenic microorganisms (harmful bacteria). Because infestations are hard to prevent at the source of production it is necessary to render harmful pathogens inactive before they enter our food supply chain.
To improve food safety and extend shelf-life the number of pathogens need to be reduced before consumption. In addition to liquids such as milk, it is now recommended for dry products such as nuts, seeds, grain and spices to be pasteurized.
After several outbreaks of foodborne illness in the US due to Salmonella (involving dry products such as almonds and grain) the USDA issued new food safety legislation in 2007 concerning the treatment of almonds with a 4 Log reduction.
Pasteurization vs Sterilization
Today, the killing of germs in food processing to enhance food safety or to extend shelf life has become standard procedure. Treatment with heat is very common, especially for foods which have favorable conditions for the growth of bacteria.
Two common treatments for the killing of pathogens are the thermal processes Pasteurization and Sterilization.
Pasteurization is performed on all types of perishable foods for food safety:
Designed to reduce the number of viable pathogens with such numbers so they are unlikely to cause disease.
Not sufficient to prevent microbiological growth in the long term.
Spore forming bacteria and moulds will be able to sprout after pasteurization, creating a new investation.
Mild treatment with minimal changes to product structure.
Typical time-temperature combinations for wet products 2 mins at 72 °C (1bar).
FDA recommend 5 log reduction of the most pertinent pathogen in this type of food available for for example fruit juice (e.g. Salmonella, Eschirichia Coli O157:H7 or Cryptosporidium parvum).
Sterilization is performed on all types of perishable foods for food safety:
Sterilization creates a product which is fully cooked, altering the product completely (e.g. canned foods).
Typical time-temperature combinations for wet products 15 mins at 121 °C (1bar).
Targets spores, to prevent regrowth in aqueous media after the sterilization step.
Generally accepted performance indicator is a 12 log reduction.