Enhanced Control of Microbiological Contamination of Product at a Large Beef Packing Plant

摘要

Swab samples were obtained from groups of 25 carcasses at various stages of processing at a large beef packing plant. The log mean number of aerobes recovered from carcasses after skinning was 2.2 log CFU/cm~2. Spraying the uneviscerated carcasses with 5% lactic acid reduced the numbers of aerobes by about 1 log unit; but subsequent carcass dressing operations, a second treatment with 5% lactic acid, pasteurizing, and carcass cooling had no substantial effect upon the number of aerobes on carcasses. The total numbers of coliforms or Escherichia coli cells recovered from skinned carcasses were <2 log CFU/ 2,500 cm~2. The numbers were reduced by the washing of uneviscerated carcasses but increased after evisceration operations. The numbers were reduced by spraying with lactic acid and pasteurizing, with no coliforms or E. coli being recovered from pasteurized carcass sides. No coliforms or E. coli cells were recovered from the forequarters of cooled carcass sides, but E. coli cells were recovered from the hindquarters of 1 of 50 cooled carcass sides, at 1.4 log CFU/1,000 cm~2. The numbers of aerobes on conveyor belts in the carcass breaking facility were similar to the numbers on cooled carcass, but the numbers of aerobes on cuts and trimmings and the number of coliforms and E. coli cells on the products and belts were higher than the numbers on carcasses. The findings indicate that most cooled carcasses produced at the plant carry E. coli at numbers <1 CFU/10,000 cm~2 but that product can be contaminated with small numbers of E. coli (<1 CFU/100 cm~2) during carcass breaking.