Volume No. 5 Issue No.: 2 Page No.: 384-392 October-December 201

 

STUDIES ON PROTEOLYTIC THERMODURIC PSYCHROTROPHIC BACTERIA IN MILK AND FERMENTED MILK PRODUCTS

 

Neeta V. Mane* and M. B. Gandhi

Department of Microbiology, Yashwantrao Chavan College of Science, Karad, Vidyanagar, Karad, Dist. Satara, Maharashtra (INDIA)

 

Received on : July 14, 2010

 

ABSTRACT

 

Pasteurization is adopted for making milk free from milk borne organisms. However thermoduric psychrotrophic bacteria that are capable of surviving pasteurization temperature and are able to grow in a cold environment (7°C) may grow in milk and fermented milk products during refrigerated storage. Thus they represent a significant spoilage problem in the storage of refrigerated dairy products. They also produce heat resistant exoenzymes such as protease, lipase etc. which withstand pasteurization and may function during cold storage and attack protein and fats in milk and milk products, thereby producing defects such as sour milk, gassiness, rancidity, bitter milk etc. Due to spoilage activities of thermoduric psychrotrophs studies were undertaken on these organisms. For studying thermoduric psychrotrophs, milk and fermented milk products were collected from five different dairies of Kolhapur region in Maharashtra, India. Total thermoduric psycrotrophic count and seasonal variations in that were determined. In all 36 isolates were obtained, of these three isolates of gram positive bacteria were identified as Macrococcus equipercicus, Exiguobacterium sp., Arthrobacter sp. on the basis of morphological, biochemical, physiological features as well as 16S rRNA sequencing. Proteolytic activities of these isolates were analyzed by qualitative and quantitative methods. All were positive for proteolysis, whereas Macrococcus sp. showed greater proteolytic activity than Exiguobacterium sp. and Arthrobacter sp.

 

Keywords : Pasteurization, Thermoduric psychrotrophs, Proteolytic, 16S rRNA sequencing, Bacteria

 

 

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