Identification of Bacteria in “REAL GOOD Sereal Coklat” UHT Milk

Abstract

MIlk is considered as one of the most nutritious drinks produced by mammals. However, milk is also perishable due to its nature. In the milk industry, heat treatment, such as Ultra HIgh Temperature (UHT) is commonly applied to extend the shelf life of the milk and inactivate unwanted microorganisms and undesirable enzymes. UHT treatment sterilizes the milk from the presence of vegetative cells and spores of bacteria. However, the presence of bacteria in sterilized products still has a chance to occur, which is indicated by pH drop. This study focuses on the identification of bacteria genus in the milk indicated by pH drop from 6-7 until 5.25-5.28 through biochemical tests (gram staining, catalase and oxidase test) and media selection were used to support the identification. There are also 4 factors of the possibility in bacteria survival in the milk processing, such as heat resistance bacteria, chemical resistance bacteria, spore-forming bacteria, and biofilm formation. A finding of bacterial growth in 4 of 15 samples results in 3 suspected bacteria, which consist of Acinetobacter, Staphylococcus, and Bacillus genus. Some of the limitations in this study include lack of proper replication and limited material and equipment. There are several applicable improvements in keeping the milk quality, such as analyzing the flush water in the cleaning process, the use of ATP sensor, UV radiation, and natural antimicrobial to the milk.