Incidence of pathogenic bacteria in raw milk in Ireland

Abstract

Raw milk from 70 farms was sampled over 13 months for salmonellas, listerias, Escherichia coli, Staphylococcus aureus and mastitic streptococci; total bacterial counts (TBC), coliforms and somatic cells were also counted. TBC < or = 30,000/ml were obtained in 63% of samples. High count milks were found mainly during the winter months: 13% of samples had > 10(4) mastitis pathogens/ml of milk. The mean somatic cell count varied from 4.0 x 10(5) to 8.0 x 10(5)/ml throughout the year with highest counts during the late lactation period. Coliforms were present in all samples, but 65-71% of samples had < 100 coliforms/ml. Up to 60% of supplies had < or = 10 E. coli/ml. One of the 589 samples tested (0.1%) was positive for salmonellas. Yersinia enterocolitica and Y. enterocolitica-like organisms were isolated from 39% of samples with up to 68% of samples positive at some sampling periods. A total of 222 strains of yersinias were isolated; Y. enterocolitica (59%) was the most common strain followed by Y. fredriksenii (35%), Y. kristensenii (1.0%), Y. intermedia (4.5%) and Y. aldovae (0.5%). Listerias were isolated from 8.3% of samples tested; 4.9% were Listeria monocytogenes and 3.4% were L. innocua. There was a significant rise in the isolation rate between December and April from a base line of 0-5% during the spring and summer to 35-37% during the winter months while the cows were indoors. Of 66 silage samples tested from the farms involved in the survey 9% of samples were positive for listerias; 3% of these were L. monocytogenes and 6% were L. innocua.(ABSTRACT TRUNCATED AT 250 WORDS)

Türkiye’nin Güneydoğu Bölgesi’nde Üretilen Mısır Silajı ve Çiğ Sütlerde Listeria Türlerinin Varlığı

“…In our study, the pH values of the Listeria spp.-positive silage samples ranged from 4.05 to 5.77 and the pH value of the silage samples contaminated with L. monocytogenes was higher than 5.5. In other studies, pH values were reported between 5.1 to 8.3 by Taşçı et al [12] , 3.8 -5.2 by Rea et al [22] , <4 -5.89 by Ryser et al [10] and 4.47 -6.97 by Vilar et al [11] . However, Ryser et al [10] could not identified L. monocytogenes in 3 Listeria spp.-positive grass silage samples were all of poor quality, ranging in pH from 5.78 to 5.89.…”

The immunological consequences of pasteurisation: Comparison of the response of human intestinally-derived cells to raw versus pasteurised milk

“…Pasteurisation, a process whereby raw milk is heated to 72 C for 15 s, was introduced to protect consumers against pathogenic bacteria that can contaminate milk, and to extend its shelf life (Rea, Cogan, & Tobin, 1992;Ternstrom, Lindberg, & Molin, 1993). Pathogenic bacteria associated with raw milk include Escherichia coli O157, Staphylococcus aureus, Mycobacterium paratuberculosis and Listeria monocytogenes (Rea et al, 1992). Indeed, even though raw milk consumption according to European legislation drafted by the European Food Safety Authority is legal, the Food Safety Authority of Ireland (FSAI) still advises against the consumption of non-pasteurised milk (Commission, 2013;FSAI, 2009).…”

Listeria monocytogenes in Milk Products

“…In Ireland the incidence was 3% (Rea et al 1992), and 6% (Fox et al 2011a), in Northern Ireland 8.8% (Harvey and Gilmour 1993), in the USA 19.7% (Latorre et al 2009), 1% (Waak et al 2002), 4.1% (Rohrbach et al 1992) and 0% (D'Amico and Donnelly 2010). Other reported incidences include 1.7% in Iran years, it is difficult to compare these reported incidences.…”