MANUFACTURE OF FLAVOURED PASTEURIZED MILK SACHETS WITH HIGHER SENSORY QUALITIES AND LONGER SHELF LIFE UNDER REFRIGERATED CONDITION

Abstract

Rich Life Dairies is a company which collects milk from local dairy farmers and processes them into various dairy products marketed under the brand Rich Life.Among other fluid milk based products, Rich Life flavoured pasteurized milk sachets have a prominent ranking. These milk sachets only have an estimated 4 days of shelf life which has created a lower demand for sachets in the market. The present study was focused on the identification of causative factors leading to the limited shelf life of pasteurized milk sachets and the application of necessary corrective measures to improve the shelf life o f the product. The determination o f shelf life of milk sachets with better sensory qualities under refrigerated condition (4°C) and available transportation conditions were also expected. The quality of milk was assessed from the point of receiving raw milk which was subjected to routine platform tests. Every production step until the finished product is obtained was investigated to identify the factors which limit the shelf life of pasteurized milk sachets. Pasteurization efficiency was tested by using the phosphatase test and every sample was identified to be phosphatase negative. Shelf life of sachets under refrigerated conditions (4°C) was determined through microbiological examinations and using sensory analysis techniques during a period of one month. According to the results, Flavoured Pasteurized milk sachets could be kept for 19 days at 4°C with no difference in taste from sachets freshly produced. But the odour was slightly deviated from that of the fresh ones after a lapse o f 7days. The shelf life of milk sachets which were kept under the existing transportation conditions showed 15 days of shelf life. This taste and odour losses during the shelf life period could be minimized by using a strong flavour additive. The major causative factors that limit the shelf life are presumed to be poor microbial quality of raw milk, unsatisfactory condition during the transportation and poor storage in retail shops. Hence it can be concluded that the shelf life can further be extended by improving the quality o f raw milk, storing the finished products under refrigeration immediately after packing and maintaining the chilled conditions during transportation and storage in retail shops.