THE CONTAMINATION OF PORK WITH SPOILAGE BACTERIA DURING COMMERCIAL DRESSING, CHILLING AND CUTTING OF PIG CARCASSES

Swab samples from the surfaces of carcasses and cuts were obtained at various stages of the dressing, chilling and cutting operations in three pig processing plants. The aerobic microflora obtained those swabs were enumerated and characterized. The flora on the skins of carcasses exiting the scalding tanks were dominated by Gram-positive organisms, with numbers about 10(3)/cm2. After dehairing, numbers were about 10(4)/cm2 with major fractions of Gram-negative organisms. Flora numbers and compositions were largely unaltered after the singeing operations, but lesser numbers were recovered after the carcasses were polished. Carcass dressing did not change the numbers on the skin. During the chilling of carcasses, the flora at two large plants altered little, but drying of the carcass surfaces at a smaller plant reduced the Gram-negative fraction of the flora. Numbers on serous and fat surfaces exposed during the dressing and cutting of carcasses were initially about 10(2)/cm2. That number was approximately maintained on finished skinned cuts produced at the smaller plant, but further contamination with lactobacilli and Brochothrix thermosphacta occurred during cutting. At the larger plants, the flora on skinned cuts were similar to those on skins, although further contamination with B. thermosphacta occurred at one plant.