Enumeration of total airborne bacteria, yeast and mold contaminants and identification of Escherichia coli O157:H7, Listeria spp., Salmonella spp., and Staphylococcus spp. in a beef and pork slaughter facility.

摘要

Environmental air monitoring programs can be employed to reduce unsanitary conditions in animal slaughterhouses due to suspended bacterial particles in the air. The main objectives of this study were to enumerate total airborne bacteria and yeast and mold contaminants and determine the presence of Escherichia coli O157:H7, Listeria spp., Salmonella spp., and Staphylococcus spp. in bioaerosols generated in a slaughter facility and on pork and beef carcasses. Air samples were taken before and during three separate pork and beef slaughter processes at the bleeding area, hide removal or dehairing area, back splitting area and holding cooler using an Andersen N6 single stage impactor. Pork and beef carcass surface bacterial swabs were collected from five different carcass sides which had been held in the holding cooler at 0°C for 12 hours.;Total airborne bacterial (TAB) counts (log CFU/m3 of air) were generally higher during slaughtering than before slaughtering. TAB counts were greater than three logs during slaughtering and less than three logs before slaughtering. The holding cooler had TAB counts less than or equal to two logs. Similar recovery rates for Staphylococcus, Escherichia and Salmonella species were obtained through direct air and enriched air microbiological sample analysis methods. Most of the Gram negative airborne bacteria isolated during slaughtering were from the Enterobacteriaceae and Pseudomonadaceae family. The predominant Gram positive airborne bacteria isolated during slaughtering were Staphylococcus, Microbacterium, Bacillus and Micrococcus species. Potentially pathogenic Staphylococcus aureus, Escherichia coli and Salmonella spp. were isolated from bioaerosols generated during slaughtering and from pork and beef carcasses. Neither Listeria spp. nor Escherichia coli O157:H7 were insolated from air samples or pork and beef carcasses.;The isolation of various microorganisms, including Staphylococcus, Escherichia, and Salmonella spp., from air samples and carcass swabs support the theory that bioaerosols transport bacteria and contribute to contamination of pork and beef carcasses. The determination of the levels and types of airborne bacterial contaminants present in a small scale slaughter facility has various implications. The effectiveness of a plant's sanitation program can be evaluated and the sources of airborne contamination can be determined allowing for increased food safety.