Introduction to Foodborne Pathogens

Food microbiology is a branch of microbiology that focuses on the study of microorganisms that are associated with food intended for human or animal consumption. Microorganisms use food as a source of nutrient for survival and growth or a vehicle of transmission to the human or animal host. Food microbiology is broadly classified into three focus areas: beneficial microorganisms, spoilage microorganisms, and pathogenic microorganisms. Beneficial microorganisms are those used for making traditional or ethnic fermented products, and as probiotics, which are gaining increased popularity because of their health-beneficial effects. Spoilage microorganisms, on the other hand, are responsible for product spoilage and place an economic burden on the producers, processors, and retail store owners for product losses. This is a serious issue in developing countries because of inadequate processing and refrigeration facilities. Foodborne pathogen contamination in foods presents a serious challenge which may result in severe diseases such as food intoxication, toxicoinfection, and infection. Mortality, morbidity, and product recalls are serious consequences of outbreaks caused by foodborne pathogens. Most foodborne pathogens grow in the mesophilic range and a few in the psychrophilic range and their growth does not usually alter the aesthetic quality of foods. Some pathogenic traits are sometimes acquired through plasmids, transposons, bacteriophages, or through pathogenicity islands. Foodborne pathogens can be zoonotic, geonotic, or human origin, and consumption of contaminated foods results in foodborne diseases. In order for a foodborne pathogen to cause disease, the microbe must be able to survive in food and, when transferred to human hosts, find niches, multiply, and express virulence factors to cause host cell damage. Worldwide, foodborne pathogens are responsible for large numbers of outbreaks, illnesses, and mortalities. Foodborne pathogens are a serious public health concern, and outbreaks are attributed to the emergence of new pathogens and reemergence of some old pathogens. The routine epidemiological and food product surveys are introduced by many countries in order to provide an accurate picture of global distribution and occurrence of foodborne diseases. The reasons for the emergence of increased foodborne diseases have been investigated. Several factors are thought to be responsible: improved survey system and the creation of the database for various pathogens; changes in agricultural and food manufacturing practices; consumer’s habits of food consumption and preparation; the increased population of the susceptible group; improved survival and adaptation of pathogens in harsh food environments; and improved detection methods. To control foodborne pathogen-related illnesses and deaths, the US government has passed the Food Safety Modernization Act (FSMA) in 2011 as a science-based proactive preventive strategy rather than a reactive passive approach to the food safety. Globally, food safety is a major concern due to increasing numbers of food- and water-associated illnesses and mortality, the emergence of highly infectious diseases from bush meats derived from wild animals, travel-associated intercontinental transfer of pathogens, and globalization of food supplies.