Efficient milking hygiene reduces bacterial spore contamination in milk

Abstract

Clostridia in the milk can lead to late blowing, a cheese defect. Clostridia are ubiquitous, deriving from both the farm environment and the feed ingested by the cows, and are transferred into the milk through faecal contamination. Our aim was to investigate the effect of different in-parlour practices on the content of anaerobic spore-forming bacteria in milk, and to monitor the variation in spore content in the feed and environment. The experiment, conducted in an experimental dairy during autumn, was repeated in exactly the same way for two consecutive years. The experimental design applied three different milking routines in three consecutive 7-d periods: forestripping alone (F); forestripping and post-dipping (F+Post); pre-dipping, wiping, forestripping and post-dipping (Pre+F+Post). Teat skin swabs and samples of feed, faeces, bedding materials and milk were collected for microbiological analyses. The dietary forage of the lactating cows included maize silage, which, in both years, was found to have the highest level of clostridial spore contamination. Pre-dipping with a detergent/emollient solution, and drying with a disposable paper towel, proved much more efficient in reducing spore contamination than forestripping alone, both on the teats (1·30 vs. 2·20 log10 MPN/swab; P < 0·001) and in the milk (1·82 vs. 2·47 log10 MPN/L, P < 0·02), while post-dipping had little influence on spore count. The standard plate count in milk was significantly lower with Pre+F+Post treatment than with F (3·80 vs. 4·51 log10 CFU/mL, P < 0·01). The teat preparation procedure did not influence the lactic acid bacterial levels in the milk, which is very positive in that decreased lactic acid bacterial content can lessen raw milk cheese quality.

The use of integrated data collection system to evaluate milking performance, microclimatic condition and cows’ behaviour

“…Drying procedure, which is useful to remove pre-dipping detergent and to avoid milk contamination through bacteria presence on the teat surface, resulted to be the most time consuming operation (6.27 ± 2.83 s). Total preparation time per cow was determined by the sum of different factors such as the number of operations performed, and how fast and scrupulous the workers are (Smith et al 2005); a complete udder preparation (pre-dipping, washing, forestripping, postdipping) can improve hygienic milk quality, as reported by Bava et al (2017). Total stimulation time, as the time from the first touch of the teat till the attach of the cluster, is a function of total preparation time per cow and the moving time of the milker.…”

Bedding and bedding management practices are associated with mesophilic and thermophilic spore levels in bulk tank raw milk

“…This study identified and quantified a direct relationship between spore levels in used bedding and raw milk: BT raw milk spore levels increase with used bedding spore levels. Previous studies have investigated transmission of spores from environmental sources, including used bedding, to BT raw milk and have proposed that used bedding influences spore levels in raw milk via contamination of the udder and teats (Slaghuis et al, 1997;Magnusson et al, 2007a;Vissers et al, 2007a;Bava et al, 2017). In the case of TS farms where milking occurs in the housing area, spores in used bedding may also influence BT raw milk spore levels via contamination of the milking apparatus (e.g., in the event of a milking unit kick-off).…”

Impacts of Milking and Housing Environment on Milk Microbiota

“…Quintana et al adopted a MALDI-TOF approach to study possible contamination routes of on sheep's milk microbiota on a farm and demonstrated that the farming practices was the main factor for milk contamination [15]. Moreover, the development of culture-independent methods and high-throughput DNA sequencing techniques have improved the approach to study microbiota communities in milk and milk products [10,[16][17][18][19][20][21]. For instance, the high-throughput DNA sequencing technique can discover more viable but non-cultivable microorganisms, extremely rare microorganisms in the community can now also be detected, and it can more accurately determine the relative abundance of various microorganisms in the environment.…”