No seasonal effect on culturable pseudomonads in fresh milks from cattle herds

Abstract

Freshly drawn raw milk from 37 single herds on farms manufacturing raw cow cheese under the Protected Designation of Origin (PDO) label were sampled over 13 mo for pseudomonad counts. Coliforms, somatic cells, and coagulase-positive staphylococci were counted and total fat and protein contents measured. For pseudomonad counts, the overall mean value was 3.60×10(3) cfu/mL. We observed very high variation between different producers and within the same producers (average standard deviation 1.30×10(4) cfu/mL), but we did not detect a seasonal effect. The only statistical correlation with other milk quality parameters was with coliforms. A survey of milking practices and milking machine sanitation together with environmental and milk sampling for pseudomonad counts in 7 cheese workshops showed that no real negligence or error could be imputed to producers. The main problems were the presence of non-aeruginosa pseudomonads in potable water and a few isolated failures during the cleaning and rinsing phases of sanitation.

Dissemination and persistence of Pseudomonas spp. in small-scale dairy farms

“…All in all, these results highlight that the frequency of Pseudomonadaceae in dairy farm is high in all sample typologies, however no difference among proportions was observed among farms and seasons, therefore implying a constant environmental contamination. Considering that water is one of the most acknowledged sources of these family of Gram negative bacteria (Leriche et al , 2004 ; Leriche and Fayolle, 2012 ) our results confirmed that Pseudomonas spp. is present in water used in primary production, both in well waters and in potable water, as already suggested (Leriche and Fayolle, 2012 ).…”

“…Considering that water is one of the most acknowledged sources of these family of Gram negative bacteria (Leriche et al , 2004 ; Leriche and Fayolle, 2012 ) our results confirmed that Pseudomonas spp. is present in water used in primary production, both in well waters and in potable water, as already suggested (Leriche and Fayolle, 2012 ). The high frequency of positive in drains and in teat coups indicates that microbes are still present and alive after the sanitising procedures as well.…”

“…may contaminate raw milk via biofilms in the milk tanks, contaminated water, or soil, few studies have been conducted focusing on primary production. For example, some authors (Leriche and Fayolle, 2012 ) revealed the presence and the level of Pseudomonas spp. and related species in milk just after milking and identified hygienic programmes and water quality as the most influential control measures.…”

N2 Gas Flushing Alleviates the Loss of Bacterial Diversity and Inhibits Psychrotrophic Pseudomonas during the Cold Storage of Bovine Raw Milk

“…The species, originally isolated from natural mineral water, is lipase- and phospholipase- negative, produces a fluorescent pigment on KB medium, is capable of growth at 4°C, and exhibits physiological flexibility during periods of anoxia [ 45 , 46 ]. Several reports highlighted the crucial role of water as a major source of pseudomonal contamination of milk [ 5 , 47 – 49 ]. All preceding observations could explain why OTU 0001 was equally dominant in the initial stages of the analyses but also in cold-stored milk where the O 2 tension is lower because of excessive bacterial growth, or in N 2 -flushed milk where O 2 is absent.…”

Quality and Safety of Bovine Raw Milk: Present Challenges and Technological Solutions

“…i v. Water and beddings: when employed for milk production, water should be of high microbiological quality as either pathogenic or saprophytic bacteria present in water can contaminate raw milk. Several reports highlighted the crucial role of water as a major source of pseudomonal raw milk contamination [8][9][10]. Beddings materials may, especially at winter, carry high bacterial loads (10 8 -10 10 cfu/g), which may contaminate teats [11].…”