Bacterial contamination of processed poultry

Abstract

Results from the bacteriological examination of uneviscerated, cooled eviscerated, and frozen eviscerated poultry carcasses from six different processing plants are presented. Eighty‐three per cent of the uneviscerated carcasses had total bacterial counts (on nutrient agar incubated at 22° C for 3 d) of less than 250,000 on a 16 cm² area of breast skin. The relative percentages for cooled and frozen eviscerated carcasses were 65.4 and 64.7 respectively. Over 90 per cent of the uneviscerated and frozen eviscerated carcasses had coli‐aerogenes counts of less than 1000 per 16 cm². Only 59.6 per cent of the cooled eviscerated carcasses were in this category. The cooled eviscerated carcasses carried more faecal streptococci than the uneviscerated and frozen eviscerated (79.8, 92.4 and 93.0 per cent respectively had less than 10,000 streptococci per 16 cm²). Of all carcasses, 66.8 per cent carried less than 100 Staphylococcus aureus per 16 cm² while 3.2 per cent carried more than 1000. A regression of total count on nutrient agar on the counts on the selective media showed that none of the regression or correlation coefficients for the uneviscerated carcasses was significant; for the cooled eviscerated carcasses (all plants) and the frozen eviscerated carcasses (plant F), both the coli‐aerogenes and faecal streptococcal counts were significantly correlated.