Management practices and forage quality affecting the contamination of milk with anaerobic spore-forming bacteria

BACKGROUND: Anaerobic spore-forming bacteria (ASFB) in milk derive from the farm environment, and the use of silages and management practices are the main responsible of milk ASFB contamination. The aim of this study was to evaluate the relationshipsbetween feeding, milking routine and cowhygiene and milk andGrana Padano cheese (produced with andwithout lysozyme) ASFB contamination. RESULTS: The study involved 23 dairy farms. ASFB in corn silage were on average 2.34±0.87 log10 MPN g-1. For grass, Italian ryegrass and alfalfa, ASFB (log10 MPN g-1) were numerically higher for silages (3.22) than hays (2.85). The use of corn silages of high quality (high lactic and acetic acids concentrations) decreased the milk ASFB contamination, whilst the use of herbage silages did not affect it. The presence (>40%) of cows with dirty udders increased the ASFB contamination of milk, while forestripping had a positive effect (-9%ASFB). RipenedGrana Padano had an ASFB count belowthe analytical limit; Clostridium tyrobutyricum DNA was found only in wheels produced without lysozyme, which also showed late blowing. CONCLUSION: The factors increasing milk spore contamination were corn silage quality, cow udder hygiene and inadequate milking routine. Late blowing was present only in cheeses without lysozyme. © 2014 Society of Chemical Industry