Microbiological Quality of Raw Goat's and Ewe's Bulk-Tank Milk in Switzerland

Abstract

A total of 407 samples of bulk-tank milk (344 of goat's milk and 63 of ewe's milk) collected from 403 different farms throughout Switzerland, was examined. The number of farms investigated in this study represents 8% of the country's dairy-goat and 15% of its dairy-sheep farms. Standard plate counts and Enterobacteriaceae counts were performed on each sample. Furthermore, the prevalence of Staphylococcus aureus, Campylobacter spp., Shiga toxin-producing Escherichia coli, Salmonella spp., and Mycobacterium avium ssp. paratuberculosis was studied. The median standard plate count for bulk-tank milk from small ruminants was 4.70 log cfu/ml (4.69 log cfu/ml for goat's milk and 4.78 log cfu/ml for ewe's milk), with a minimum of 2.00 log cfu/ml and a maximum of 8.64 log cfu/ml. Enterobacteriaceae were detected in 212 (61.6%) goat's milk and 45 (71.4%) ewe's milk samples, whereas S. aureus was detected in 109 (31.7%) samples of goat's milk and 21 (33.3%) samples of ewe's milk. Campylobacter spp. and Salmonella spp. were not isolated from any of the samples. However, 16.3% of the goat's milk and 12.7% of the ewe's milk samples were polymerase chain reaction (PCR)-positive for Shiga toxin-producing E. coli. Seventy-nine (23.0%) goat's tank-milk and 15 (23.8%) ewe's tank-milk samples were PCR-positive for insertion sequence 900, providing presumptive evidence for the presence of M. avium ssp. paratuberculosis. These results form the basis for determining the microbiological quality standards for goat's and ewe's milk. Moreover, the data presented form part of the risk assessment program for raw milk from small ruminants in Switzerland.

Qualidade higiênica de leite caprino por contagem de coliformes e estafilococos

“…Na Itália, foi verificada média de 1,2x10 4 UFC mL -1 de S. aureus, em 43% das amostras de leite de mistura analisadas (FOSCHINO et al, 2002), e, na Suíça, este microrganismo foi observado em 31,7% das amostras analisadas (MUEHLHERR et al, 2003 alimentos. Comparando-se os valores de coliformes totais e fecais e estafilococos observados entre as propriedades que utilizam ordenha mecânica e aquelas que empregam a ordenha manual, não houve diferença estatística significativa (P>0,05).…”

“…Por outro lado, amostras de leite armazenadas em latões imersos em água refrigerada por até três dias apresentaram contagem máxima de 1x10 2 UFC mL -1 de coliformes fecais (MURICY et al, 2002) no RS e na Suíça, sendo que 61,6% das amostras coletadas em tanques de expansão apresentaram enterobactérias (MUEHLHERR et al, 2003).…”

Detection methods for Mycobacterium avium subsp paratuberculosis in milk and milk products: a review

“…However, potential MAP contamination of milk from other ruminant species remains to be elucidated. In sheep and goats, MAP was detected by means of IS900 PCR in 23% of bulk tank milk samples from 403 different farms throughout Switzerland in the year 2003 (Muehlherr et al, 2003). The first report of isolation of cultivable MAP from goat's milk originated from India (Singh and Vihan, 2004).…”

Mycobacterium avium subsp. paratuberculosis in powdered infant milk: paratuberculosis in cattle - the public health problem to be solved

“…In Switzerland, 19.7% of bulk-tank milk samples were IS900 PCR positive (Stephan et al, 2002). Goat's tank-milk and ewe's tank-milk samples were also PCR-positive for the IS900 (23.0 and 23.8%, respectively), providing presumptive evidence for the presence of MAP in Switzerland (Muehlherr et al, 2003). MAP has been cultivated from cheese (Mason et al, 1997;Donaghy et al, 2004;Stabel and Lambertz, 2004;Ikonomopoulos et al, 2005) as well.…”