Impacts of Milk Microbiota Composition on Whey Quality in California

RESEARCHER: Maria Marco, UC Davis

TIMELINE: January 2021 to December 2022

BACKGROUND: Annual losses to the U.S. dairy industry due to unwanted microbial loads and product defects in whey powder is in the $5 – 10 million range. The value and marketability of whey products are highly dependent on whey quality, with microbiological quality having paramount importance. There is currently no reliable information on the sources affecting the microbial contents (species/strains and tota loads) in whey. It is possible that milk-associated, thermoduric bacteria survive milk processing and cheese production, and ultimately negatively affect whey powder quality.

OBJECTIVE: To identify sources of microbial contaminants in whey powder in order to determine whether milk is the main source of microbial contaminants in whey powder produced in California. Determine microbial genotypes consistent with increased survival in whey powder to identify control points that may be used to minimize microbial survival and contamination of whey.

INDUSTRY BENEFIT: The California dairy industry will gain first-hand knowledge on the dominant microbial contaminants in whey powder and any relationships between those contaminants and bacteria entering whey powder via raw milk. The thermoduric bacteria and genes associated with whey powder contamination will be known and therefore can be targeted in subsequent methods aimed at eliminating those bacteria whey products.