Biodiversity of culturable psychrotrophic microbiota in raw milk attributable to refrigeration conditions, seasonality and their spoilage potential. (June 2016)

• Record Type: Journal Article
• Authors: Vithanage, Nuwan R.; Dissanayake, Muditha; Bolge, Greg; Palombo, Enzo A.; Yeager, Thomas R.; Datta, Nivedita
• Is Part Of: International dairy journal. Volume 57(2016:Jun.)
• Page Start: 80
• Page End: 90
• Publication Date: 2016-06
• Subjects: Dairying -- Periodicals; Industrie laitière -- Périodiques; Electronic journals; 338.1762142
• DOI: 10.1016/j.idairyj.2016.02.042
• Languages: English
• ISSNs: 0958-6946

Abstract

Abstract: Refrigerated storage of raw milk promotes the growth of psychrotrophic bacteria, some of which produce heat-stable exoenzymes causing dairy product spoilage. The effects of storage conditions and season on the biodiversity of psychrotrophs in raw milk were examined using matrix-assisted laser desorption time of flight mass spectrometry and 16S rRNA analysis. The ability of psychrotrophs to produce protease, lipase and phospholipase C was determined. The predominant genera found were Pseudomonas (19.9%), Bacillus (13.3%), Microbacterium (5.3%), Lactococcus (8.6%), Acinetobacter (4.9%) and Hafnia (2.8%); a considerable number of isolates were hitherto unknown species and genera. Diversity varied significantly ( P < 0.05), depending on the storage temperature, time, initial microbiota and season. The predominant isolates showed significantly higher heat-stable exoenzyme activities after heating at 142 °C for 4 s. Improving the quality of milk products may require differential processing of raw milk depending on the type of microbiota present, storage temperature and seasonality.