title: Management practices and forage quality affecting the contamination of milk with anaerobic spore-forming bacteria.
abstract: 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 relationships between feeding, milking routine and cow hygiene and milk and Grana Padano cheese (produced with and without 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). Ripened Grana Padano had an ASFB count below the analytical limit; Clostridium tyrobutyricum DNA was found only in wheels produced without lysozyme, which also showed late blowing.
  
  
  CONCLUSIONS
  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.
authors.affiliation: Università degli Studi di Milano, Dipartimento di Scienze Agrarie e Ambientali, via Celoria 2, 20133, Milan, Italy.
authors.forename: Maddalena
authors.initials: M
authors.lastname: Zucali
authors.forename: Luciana
authors.initials: L
authors.lastname: Bava
authors.forename: Stefania
authors.initials: S
authors.lastname: Colombini
authors.forename: Milena
authors.initials: M
authors.lastname: Brasca
authors.forename: Marilù
authors.initials: M
authors.lastname: Decimo
authors.forename: Stefano
authors.initials: S
authors.lastname: Morandi
authors.forename: Alberto
authors.initials: A
authors.lastname: Tamburini
authors.forename: G Matteo
authors.initials: GM
authors.lastname: Crovetto
mesh_terms: D000822:Animal Husbandry / Q000379:methods*; D000818:Animals; D001419:Bacteria; D002417:Cattle; D002611:Cheese / Q000382:microbiology; D003013:Clostridium; D003612:Dairying / Q000379:methods*; D005260:Female; D005516:Food Microbiology; D006801:Humans; D006920:Hygiene; D000455:Medicago sativa / Q000382:microbiology; D008892:Milk / Q000382:microbiology*; D009113:Muramidase; D006109:Poaceae / Q000382:microbiology; D012820:Silage / Q000382:microbiology* / Q000592:standards; D013171:Spores, Bacterial; D003313:Zea mays / Q000382:microbiology
chemical_list: D009113:Muramidase
keywords: Clostridium; management practices; milk; silage; spore