Effect of air hygiene in butter plant on quality of final product

In this work, results of examination of the environment impact, ie. impact on quality of packaged butter during its shelf-life depending on the air hygiene in butter plant, have been presented. Control of air hygiene was performed in two dairy plants. First control was carried out in part of the plant where churning of butter and packaging in carton boxes of 20 kg (8 different places of examination) takes place, and in the part of the plant where machines for butter packaging in smaller carton boxes of 125 g (6 places) are placed. Control of air hygiene was performed by determination of total number mesophilic aerobic bacteria (TNB), as well as total number of yeasts and molds. Air sampling was carried out by exposing the open Petri dishes with the appropriate nutrient medium (nutrient agar for TNB, and Sabouraud maltose agar (SMA) with streptomycin (from 0.01 to 0.2%) to the air of the total number of yeast and molds). Butter samples were stored in refrigerator (at temperature up to +4 deg C), in order to monitor the expiration date. Microbiological control of packaged butter on 125 g as well as block of butter of 20 kg, was controlled every tenth day within a 60 days period. The results showed that the total number of bacteria colonies in the samples of air in the production plant, ranged from 6-20 (churning), and 12-36 colonies (packing). A similar trend was observed in tests concerning the presence of yeasts and molds. Microbiological testing of samples of butter during storage at 4 deg C (storage capacity test), showed that the presence of pathogenic bacteria was not established. The increased number of aerobic mesophilic bacteria, in stored butter within smaller packaging compared to the butter in a block, is, above all, the result of a variety of manipulative actions that are performed before and during the process of packaging. This causes the increase of certain groups of microorganisms in relation to the butter in block which is immediately stored in cold storage at temperatures below 4 deg C after churning process. The largest number of mold was found in butter in 125 g packages, which was 89 cfu/g during the 60-day storage period, while in the butter block that number was lower – 22 cfu/g. Such a mycological profile of packaged butter is largely a result of the presence of mold in the air in the packaging room and their direct incorporation into the finished product.