engleski

The microbiological examination of raw goat milk and the survival of the goat milk microbiota on three different temperatures

The aim of this study was to define microbiological quality of unprocessed goat milk as well as the dynamic of multiplication of the raw goat milk bacteria on three different temperatures. The sample has been taken from a small family farm using sterile equipment in a volume of 500mL. The goat udder was washed with a warm tap water prior to milking. One milliliter of freshly obtained milk was inoculated into 10mL yeast extract agar for the determination of number of aerobic mesophilic bacteria (AMB). Total volumes of 100µL were inoculated onto VRBG, Baird-Parker and XLD agar, while 1mL of milk was pour with TNS agar for the isolation of anaerobic bacteria genus Clostridium. The milk was separated in three sterile bottles and kept in three different temperatures 4°C, 22°C and 37°C for 48 hours. Samples were tested daily and number of bacteria was monitored. According to “Guidelines of the microbiological food criteria” the number of AMB was in inside the limits proscribed by the guidelines. Salmonella, Staphylococcus and Clostridium were not detected. The Enterobacteriaceae were detected and their number was higher than the guidelines prescribe. The raw goat milk kept on +4°C resulted in inconsiderable growth of AMB while the room temperature allows significant growth of the bacteria. Interestingly, the temperature of 37°C inhibits the growth of the bacteria probably because of the activation of the enzymes which activity is most expressed on this temperatures. Since the Enterobacteriaceae were detected in higher number than the guidelines proscribe, this sample was unacceptable microbiological quality.

raw goat milk; microbiota; survival; temperature

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