Prevalence of Salmonella, Listeria Monocytogenes, Campylobacter Spp., Yersinia Enterocolitica and Cryptosporidium Spp. in Bulk Milk, Cows' Faeces and Effluents of Dairy Farms in Trinidad

The prevalence of Listeria, Salmonella, Campylobacter, Yersinia and Cryptosporidium species in bulk milk, faeces of dairy cows and effluents of milking parlours from dairy farms in Trinidad was investigated. Of the 177 bulk milk samples studied, 3 (1.7%), 3 (1.7%) and 2 (1.1%) were positive for L. monocytogenes, Salmonella spp. and Y. enterocolitica, respectively, but were all negative for Campylobacter and Cryptosporidium species. From 333 faecal samples tested, L. monocytogenes, Campylobacter spp. and Cryptosporidium spp. were detected in 11 (3.3%), 19 (5.7%) and 7 (2.1%), respectively, which were significantly (P < 0.05; chi 2) higher than the detection rate (0%) for Yersinia spp. Salmonella spp. were isolated from 3 (0.9%) of the faecal samples. From 168 effluent samples cultured, Campylobacter spp. were isolated from 7 (4.2%) samples while Salmonella was recovered from only 1(0.6%) sample with no sample positive for either Yersinia or Listeria. The difference was significant (P < 0.05; chi 2). A total of 19 (73.1%) of 26 Campylobacter isolates exhibited resistance to one or more of the six antimicrobial agents tested. All 14 (100%) isolates of L. monocytogenes were resistant to at least one agent while all Salmonella and Yersinia enterocolitica strains were susceptible to all antimicrobial agents used. It was concluded that the five enteropathogens tested were present on dairy farms in Trinidad and the potential for milk-borne diseases, due to these pathogens, exists for consumers, emphasizing the need for good sanitary practices.