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This survey investigated the antimicrobials most commonly used in dairy herds and antimicrobial residues most frequently detected in milk to evaluate the suitability of rapid screening tests to determine antimicrobial residues in milk. The investigation was carried out in 45 dairy herds consulting the farm administration records and in a national dairy industry collecting milk from almost all the dairy farms studied. Data were recorded on: i) treatments with drugs containing antimicrobials during the 12 months prior to the visit; ii) antimicrobial active substances present in the drugs; iii) data from routine controls to detect antimicrobial residues (52,771 samples). The antimicrobial classes most commonly used were penicillins, cephalosporins, fluoroquinolones, macrolides, sulphonamides, tetracyclines, aminoglycosides and lyncosamides; the most frequently used antimicrobial not belonging to any of the previous groups was riphaximin. Sixty-four samples collected from milk trucks yielded antimicrobial residues exceeding the detection limit of the screening test used: sulphonamide residues were the most prevalent (3.4%), followed by tetracycline (0.3%) and penicillins and cephalosporins (0.03%). The antimicrobial classes most commonly used on dairy farms are the same as the residues most frequently detected in milk. The association of several commercially available rapid test kits proved satisfactory for determination of the veterinary antimicrobial drugs most used on dairy farms but at least five kits are required. Therefore, knowledge of the most frequently used veterinary drugs and periodic monitoring are required for the dairy industry to develop a targeted and effective control plan. [ABSTRACT FROM AUTHOR]

Water buffalo mozzarella cheese (WBMC) is a fresh pasta filata cheese produced from whole chilled buffalo milk. Although pasteurization of milk and the use of defined starter cultures are recommended, traditional technology involving the use of unpasteurized milk and natural whey cultures is still employed for WBMC production in Italy. The aim of this study were to assess the behaviour of Salmonella Typhimurium during the production of artisan water buffalo mozzarella cheese and during its shelf life under different temperature conditions. Raw milk was inoculated with S. Typhimurium and the evolution of S. Typhimurium count during production and shelf life was monitored. In artisan WBMC production technology S. Typhimurium multiplied in the curd during ripening, but its growth rate expressed in log CFU/g/h was lower than the growth rate reported by theoretical predictions. Stretching proved to be a process with good repeatability and able to reduce S. Typhimurium contamination by 5.5 Log CFU/g. The intrinsic characteristics of traditional WBMC proved to be unable to obstacolate the growth of S. Typhimurium during storage in the case of thermal abuse. Control of raw milk contamination and a proper refrigeration temperature are key factors in reducing the risk for consumers. [ABSTRACT FROM AUTHOR]