Determinazione del contenuto di anaerobi sporigeni in latte e prodotti del settore lattiero caseario

In the absence of an official method, anaerobic sporeforming bacteria in milk products are commonly determined by the Weinzirl technique, based on gas formation in tubes containing different dilutions of pasteurized sample material. This is a simple, low-cost method, but it takes 7 days and indicates only the most probable number of spores. From a study of daily data during an experimental 7-day period the relationship between recording time and validity of results was evaluated. The test material consisted of 256 samples of raw milk, 147 of cattle feed, including roughages and concentrate, and 106 of bovine faeces. A correct result could be obtained in 6 days for all sample types. For faeces and milk respectively, it took 4 and 5 days (minimum) to achieve results that were not significantly different from those obtained after 7 days.