Competitive Inhibition of E. coli 0157:H7 and Salmonella spp. in Ground Beef Products

<p>Highly publicized outbreaks of food-borne illness since 1993, primarily caused by bacteria such as E. coli O157:H7, Salmonella spp. and Listeria monocytogenes, elicited intense consumer concern about meat safety. In response, regulatory authorities, researchers and the beef industry initiated efforts to implement food safety management systems that would improve microbiological quality. The USDA Food Safety and Inspection Service (FSIS) began initiating new regulatory requirements during the mid-1990s. Packers were required to knife-trim carcasses to remove all visible contaminants, comply with written sanitation standard operating procedures (SSOP), implement Hazard Analysis Critical Control Point (HACCP) systems, and meet microbiological performance criteria and standards for E. coli and Salmonella as a means to verify HACCP effectiveness and pathogen reduction.</p>

<p>Researchers and beef packers/processors have addressed consumer food safety concerns by developing a variety of methods that are now implemented, or are being further developed, to reduce numbers of bacteria on beef and beef products and improve microbiological safety. These microbiological decontamination technologies include:</p>

<ul>
<li>Animal cleaning;</li>
<li>Chemical dehairing at slaughter;</li>
<li>Spot-cleaning of carcasses by knife-trimming or steam/hot water vacuuming; and</li>
<li>Spraying/washing/rinsing of carcasses before evisceration and/or before chilling, with water, chemical solutions and/or steam or hot water.</li>
</ul>

<p>Ground beef products are commonly implicated as sources for E. coli and Salmonella outbreaks. While many intervention technologies exist for beef carcasses, very few interventions exist that have been validated for ground beef products. Previous research has found that lactic acid bacteria (LAB) inhibit L. monocytogenes in ready-to-eat meat products. It was hypothesized that LAB, when added to ground beef, could inhibit the growth of both E. coli 0157:H7 and Salmonella spp. in ground beef stored at refrigeration temperatures.</p>