Antimicrobial activity of cetylpyridinium chloride washes against pathogenic bacteria on beef surfaces

Cetylpyridinium chloride (CPC), a water-soluble, neutral pH, colorless comp ound, is widely used in oral hygiene products to inhibit bacteria responsib le for plaque. Previously, researchers have demonstrated that CPC not only reduces Salmonella Typhimurium on poultry but also prevents cross-contamina tion. To determine the effectiveness of CPC against pathogens associated wi th lean and adipose beef surfaces, several spray-washing experiments (862 k Pa, 15 s, 35 degrees C) with 1% (wt/vol) CPC were conducted. On lean beef s urfaces, CPC immediately reduced 5 to 6 log(10) CFU/cm(2) of Escherichia co li O157:H7 and Salmonella Typhimurium to virtually undetectable levels (0 l og(10) CFU/cm(2)), as well as after 35 days of refrigerated (4 degrees C), vacuum-packaged storage. On adipose beef surfaces, 5 log(10) CFU/cm(2) Salm onella Typhimurium and E. coli O157:H7 were reduced immediately (>2.5 log(1 0) CFU/cm(2)) with 1% CPC; by day 35 the reduction was <1.3 log(10) CFU/cm( 2). Further plate overlay analyses indicated that the effectiveness of CPC against pathogens on adipose surfaces was not hampered by the presence of m eat components or fatty acids. Additional chemical and microbiological anal yses of 1% CPC-treated beef surfaces subjected to a secondary water wash (f ollowing contact times of 0, 5, 10, 15, or 30 min) or grinding did reduce p athogenic bacteria and CPC levels. However, residual CPC levels following a ny of the treatments were considered excessive for human consumption. Despi te the residual levels, this study is the first to demonstrate the effect o f CPC on pathogenic bacteria associated with beef surfaces immediately afte r treatment and also after long-term, refrigerated, vacuum-packaged storage .