ABSTRACT
Food safety and emerging food biosecurity issues are important to consumers, food manufacturers, and food producers alike. Though foodborne pathogen statistics show a slight decline in the number of cases, outbreaks and product recalls continue to exert a huge economic burden on the producers. Microbial populations in foods, food ingredients, and the food contact environment normally constitute many different species coming from different sources. The total microbial population in a food varies greatly depending upon the level of sanitation used at all phases of production, the degree of abuse that leads to microbial growth, and the processing and preservation methods used to kill and prevent growth of microorganisms. Similarly, contamination of a food by specific types or species of microorganisms is dependent on the presence or source of these microorganisms and their entrance into the food, mostly as a result of poor sanitation during handling and processing. Microbiological examination of foods and food ingredients helps one assess their safety to consumers, their stability or shelf life under normal storage conditions, and the level of sanitation used during handling. In addition, the microbiological load and type can be important in determining whether a food and food ingredient meet acceptable standards, specifications, and guidelines. Microbiological evaluation of raw materials also provides important information about the heat-processing parameters that would be necessary to meet the microbiological standard, guideline, or specification of a product. Finally, microbiological evaluation of a food, food ingredient, and environment helps determine possible sources of a specific microbial type in a food and, in the case of a thermally processed food, the source and nature of post-heat treatment contamination. Despite all precautions, pathogens are found in ready-to-eat products, which is a serious concern because these products do not receive further treatment before consumption. In fact, several foodborne outbreaks occurred because of consumption of undercooked or minimally processed ready-to-eat meats (hotdogs, sliced luncheon meats, and salami), dairy products (soft cheeses made with unpasteurized milk, ice cream, butter, etc.), or minimally processed fruits (apple cider, strawberries, raspberries, cantaloupe, etc.) and vegetables (sprouts, lettuce, spinach, etc.). Food animals and poultry are the most important reservoirs for many of the foodborne pathogens, including Salmonella, Campylobacter, Listeria, or Escherichia coli O157:H7. Animal byproducts, such as feed supplements, may transmit pathogens to other animals (e.g., Salmonella, Prion associated with bovine spongiform encephalopathy [BSE] or mad cow disease). Application of untreated manure onto farmland can also contaminate soil or water with the eventual contamination of fruits and vegetables. Seafoods are another potential source of foodborne pathogens, including Vibrio species, Listeria monocytogenes, and Hepatitis A. Infectious doses of many of these pathogens are very low (~10–1000 cells). Detection technologies, both traditional and rapid, are able to detect such low numbers, but they are lengthy and laborious. Furthermore, ongoing concern with intentional administration of harmful microorganisms or toxins in food or water supplies demands significant improvement in detection technologies for a fast time to result with a high degree of accuracy. Modern biosensor technologies are showing some promising results in pathogen detection and principles, and application of some selected technologies are presented later in this chapter.
