Current Issues Related to Meatborne Pathogenic Bacteria

Food animals may be infected, contaminated or be asymptomatic carriers of pathogenic microorganisms and together with the environment they serve as sources of contamination for carcasses during the slaughtering process and for meat products during processing, storage and handling, or for water and other foods through contaminated manure (Sofos, 2002a). Foodborne microbial hazards have a devastating impact on human suffering because they are estimated to cause approximately 76 million cases of illness, 325,000 hospitalizations, and 5,000 deaths in the United States each year (Mead et al., 1999). It is estimated that bacterial agents are responsible for only 30% of the total foodborne illnesses; however, 72% of total deaths are due to consumption of foods contaminated with bacteria (Mead et al., 1999). The United States National Health Objectives for 2010 aim at reducing the incidence of illness caused mainly by four foodborne pathogens, namely Campylobacter, Salmonella, Escherichia coli O157:H7 and Listeria monocytogenes, to 12.3, 6.8, 1.0, and 0.25 cases per 100,000 population, respectively (DHHS, 2000). According to the latest (2002) surveillance data (CDC, 2003), Salmonella are responsible for causing the highest total number of cases of gastrointestinal illness among bacteria; however, despite the high incidence of illness, the case-fatality rate is <0.05%. Campylobacter is responsible for the second highest total number of gastrointestinal illnesses and like Salmonella, it has a case-fatality rate of <0.05% (CDC, 2003). Although E. coli O157:H7 has a much lower rate of incidence compared to Salmonella and Campylobacter, this organism has a higher case-fatality rate (0.1%). Compared to the abovementioned pathogens, L. monocytogenes has the lowest rate of incidence but a significantly higher (approximately 20%) fatality rate (Mead et al., 1999). Thus, there is a need to control pathogenic microorganisms in animals and their products in order to enhance the safety of our meat supply.