Identification of Enterococci, Staphylococci, and Enterobacteriaceae from Slurries and Air in and around Two Pork Farms

Abstract

In this study, we investigated the airborne dissemination of bacteria from the inside of two very different pork farms (an intensively confined farm and an open-range farm) to the immediate environment. Samples were taken from the slurry, from the air inside the farms (area 0), and from their immediate surroundings at a distance of 50, 100, and 150 m in four directions (north, south, east, and west). A control sample in the air of a zone far away from human or animal activity was also taken. Identification of isolates was made by means of the matrix-assisted laser desorption-ionization time of flight system. A total of 1,063 isolates were obtained, of which a mere 7 came from the air of the control area. Staphylococci, enterococci, and Enterobacteriaceae were selectively targeted for isolation and represented 48.6, 27.2, and 21.6% of the isolates, respectively. The species identified from the air of surrounding areas ( Enterococcus faecalis, Enterococcus hirae, and Staphylococcus arlettae, mainly) were also present inside the farms studied. The results suggest that air is involved in bacterial dissemination, and pork farms should be considered a potential source of foodborne bacteria that might contaminate surrounding areas, including vegetable orchards. Wind direction appears as a factor involved in bacterial dispersion through the air, but its effect may be conditioned by existing vegetation and orographic conditions.

Keywords: Air; Bacteria; Dissemination; Matrix-assisted laser desorption–ionization time of flight; Pork farm.