ZOONOTIC POTENTIAL OF SALMONELLA SPP. IN RAW MILK DISTRIBUTION CHAINS IN INFORMAL MARKETS

Abstract

The study was a cross-sectional assessment of the zoonotic potential of Salmonella spp. in the raw milk distribution channels in informal market places.  We collected a total of 250 samples; 200 raw milk samples and 50 ambient swabs at dairy farms, transport system and vendor stands.  Twenty-four percent of milk samples and 30 percent of ambient samples were positive to Salmonella spp.  The most prevalent serovars were S. Enteritidis (41.3%) and S. Typhimurium (33.3%) based on molecular identification.  Antimicrobial susceptibility test revealed that, 68.4% of the isolates were resistant to ampicillin, 60.5 percent were resistant to tetracycline, and 55.3 percent were resistant to streptomycin. Also, the isolates were categorized with 39.5 percent being multidrug-resistant (MDR).  Logistic regression revealed that poor udder cleaned (OR=3.75), unclean equipment (OR=4.20), lack of cold storage (OR=2.93) and transportation delay (OR=2.15) were significantly risk factors of infections (p<0.05).  Vendor tests revealed that 72 percent of them failed to meet reasonable hygiene standards and 85 percent of the consumers interviewed never boiled raw milk prior to consuming it.  The rate of contamination was directly correlated to increased ambient temperatures and extended storage time.  These results support the high zoonotic potential of Salmonella in uncontrolled raw milk markets and highlight the need of improved hygiene control, official oversight, and consumer awareness to mitigate the health risks to the population caused by the use of raw milk in the informal sector.