Salmonella Interventions for Beef

Salmonellae are ubiquitous gram-negative bacteria, generally originating from the colonized digestive tracts of birds, reptiles, and mammals (Bacon and Sofos, 2003). Salmonellosis, the illness associated with serovars of the genus Salmonella (Varma et al., 2005), usually involves gastroenteritis and enteric fever symptoms, and is in part, transmitted through contaminated food, including various beef products. Although the majority of patients experience a 4 -7 d period of diarrhea, fever, and abdominal cramping, a fraction of patients may experience extended periods of joint pain, irritated eyes and urinary tracts, and possible development of chronic arthritis symptoms. Voetsch et al. (2004) estimated that, based on FoodNet data, the occurrence of U.S. nontyphoidal salmonellosis in the period 1996-1999 was 1.4 million cases, and a subsequent 168,000 doctor visits per annum (19961999); these culture-confirmed infections, coupled with nonculture-confirmed infections, resulted in approximately 15,000 hospitalizations and 400 deaths per annum (Voetsch et al., 2004). Although various statistics (Chalker et al., 1988; Mead et al., 1999) verify the public health risk related to Salmonella infections, the true incidence of salmonellosis is not known as many foodborne illness events go unreported; it is estimated that the causative agent is determined in less than one fifth of the estimated 76 million of the U. S. annual cases of foodborne illness (Mead et al. 1999). Various studies have determined Salmonella serotypes isolated from various sources in the environment, animals, food products and ill humans (Table 1) (Bacon et al., 2002a; Beach et al., 2002b; CDC, 2004; Schlosser et al., 2000; Sorensen et al., 2002). As indicated (Table 1), Salmonella serovars isolated from humans match those found in cattle or meat and vice versa; however, serovar predominance can vary between human, meat product, and cattle sources. This interesting observation needs further examination. As salmonellosis remains an important public health risk, there is a need for its control throughout the food production chain. In order to improve the microbiological quality and reduce presence of pathogens such as Salmonella in beef, the United States Department of Agriculture Food Safety and Inspection Service (USDA/FSIS) introduced the process management system of hazard analysis critical control point (HACCP) in meat and poultry inspection (FSIS, 1996). In addition to the concept of HACCP and the required establishment of sanitation standard operating procedures (SSOP), the new meat and poultry inspection regulation (FSIS, 1996) introduced the requirement of microbiological performance criteria as a means of HACCP verification and pathogen reduction. Established microbiological performance criteria and standards include those for Escherichia coli biotype I and Salmonella (FSIS, 1996). In order to meet these regulatory requirements and to improve the microbiological condition of meat, the industry has sought and implemented pre-harvest pathogen control strategies and carcass sanitization or decontamination interventions (Sofos, 2002; Sofos and Smith, 1998; Sofos et al., 1999a; Stopforth and Sofos, 2006). In this paper we discuss sources and extent of Salmonella contamination of fresh beef, and the interventions applied preand post-harvest for its control.