The influence of air hygiene on microbiological safety of butter

In this work, the microbial air quality in a butter factory was studied, and the microbial safety of packaged butter during its shelf-life is presented. Control of air hygiene was performed in two halls in one butter factory. The production hall housed the butter churner, and here, 20 kg blocks of butter were packaged in cardboard boxes (8 different locations were examined). The packaging hall housed a line for splitting the 20 kg blocks of butter into 125 g amounts and a butter packaging machine producing smaller cardboard boxes containing the 125 g packets of butter (6 locations were examined). The hygienic quality of air in the two halls was assessed by determining the numbers of mesophilic aerobic bacteria, yeasts and molds. Microbiological examination of bulk 20 kg butter blocks and 125 g packets of butter was conducted every tenth day over 60 days. The air in the production plant contained mesophilic bacteria that settled on plates during 20 minutes' exposure; numbers were from 620 at churning, and 12-36 colonies at packing. The mycological profile of packaged butter is largely a result of the presence of molds in the packaging hall air and their direct incorporation onto the finished product.