Microbial efficacy and impact on the population of Escherichia coli of a routine sanitation process for the fabrication facility of a beef packing plant

The aim of this study was to assess the microbiological effect of a sanitation process used at a beef fabrication facility. On each of three fabrication days and the following mornings, samples were collected from meat contacting surface (CS) and non-contacting surface of two conveyor belts and from surfaces of cuttings tables before cleaning and before work, respectively, for recovery of total aerobes, coliforms and Escherichia coli. Selected presumptive E. coli isolates from belt 2 were purified and the confirmed isolates were genotyped using multiple-locus variable-number tandem-repeat analysis (MLVA). The numbers of aerobes before cleaning were mostly 6 log cfu/1000 cm2 and were not significantly (p > 0.05) different from those before work. The log total numbers of coliforms and E. coli before cleaning and before work were largely similar. However, the numbers of samples from which no coliforms or E. coli were recovered were fewer before cleaning than before work. Of the presumptive E. coli isolates from CS and NCS before cleaning and before work, 88 (95%) and 1 (5%), and 134 (84%) and 78 (65%), respectively, were confirmed. MLVA of 89 (CS) and 212 (NCS) E. coli isolates revealed 18 and 16 distinct genotypes, respectively. Of the E. coli from CS, 98% were found at one sampling time. Of the E. coli from NCS, however, >90% were found more than once, and both before cleaning and before work. The findings show that the sanitation process did not have significant impact on the numbers of aerobes or coliforms, but was effective for removing E. coli from CS and to a lesser degree from NCS of conveyor belt.