Incidence of coagulase positive Staphylococcus on beef carcasses in three Australian abattoirs

The contamination of beef carcasses with coagulase-positive staphylococci (CPS) was studied at three beef abattoirs (A, B and C). The incidence and the number of CPS were determined on cattle hides immediately after slaughter and on three carcass sites (brisket, flank and round) at different points during processing along the slaughter line. The incidence of CPS on cattle hides ranged from 20 to 68.6%. At abattoir A, 6.5% of the carcasses sampled before evisceration were contaminated with CPS, compared to 40% of the carcasses after evisceration. The incidence on carcasses changed little during further processing; however, after chilling for 72 h, the incidence increased to 83%. After evisceration, the brisket and flank areas were more often contaminated than the round. A similar pattern of contamination was observed at abattoir B. At abattoir C, 26.7% of the samples collected before evisceration were contaminated and this fell to 16.7% after evisceration. After chilling for 72 h, the incidence of carcass contamination with CPS increased to 46.7%. The average number of CPS on contaminated carcasses prior to and after overnight chilling was less than 50 colony-forming units (cfu)/cm2 and, after weekend chilling, increased to 64 and 112 cfu/cm2 in abattoirs A and B, respectively. Of the isolates tested, 71.4% produced staphylococcal enterotoxin and 21% could not be classified phenotypically. The hands of workers and environmental sites associated with the evisceration process were examined for CPS at abattoir A. Hands were heavily contaminated and were the likely source of CPS contamination at this abattoir.