Distribution and prevalence of airborne microorganisms in three commercialpoultry processing plants

Airborne microbial contaminants and indicator organisms were monitored with in three poultry processing plants (plants A B, and C). In total, 15 cubic feet (c.f.) of air was sampled per location during 15 visits to each plant and quantitatively analyzed for total mesophilic and psychrophilic aerobic counts, thermophilic campylobacters, Escherichia coli, and Enterobacteriace ae. The prevalence of Salmonella spp. in air samples was also evaluated. Si gnificant reductions in total aerobic counts were observed between defeathe ring and evisceration areas of the three plants (P < 0.05). Mesophilic plat e counts were highest in the defeathering areas of all plants compared to e quivalent psychrophilic plate counts. Enterobacteriaceae counts were highes t in the defeathering areas of all three plants with counts of log(10) 1.63 , 1.53, and 1.18 CFU/15 c.f. recovered in plants A, B, and C, respectively. E. coli enumerated from air samples in the defeathering areas exhibited a similar trend to those obtained for Enterobacteriaceae with log(10) 1.67, 1 .58, and 1.18 CFU for plants A, B, and C, respectively. Thermophilic campyl obacters were most frequently isolated from samples in the defeathering are as followed by the evisceration areas. The highest mean counts of the organ ism were observed in plant A at 21 CFU/15 c.f. sample with plants B and C a t 9 and 8 CFU/sample, respectively. With the exception of low levels of Ent erobacteriaceae recovered from samples in the on-line air chill in plant A, E. coli, Enterobacteriaceae or Campylobacter spp. were not isolated from s amples in postevisceration sites in any of the plants examined. Salmonella spp. were not recovered from any samples during the course of the investiga tion.