Milk undergoes heat treatment — pasteurization — to kill off microbes that can cause food spoilage and disease, but certain bacterial strains can survive this heat shock as spores and cause milk to curdle in storage.
Researchers in the Milk Quality Improvement Program at Cornell’s College of Agriculture and Life Sciences have identified the predominant spore-forming bacteria in milk and their unique enzyme activity, knowledge that can now be used to protect the quality and shelf life of dairy products.
“We studied 1,288 bacterial isolates in raw milk, pasteurized milk and the dairy farm environment; however, only a handful of strains accounted for 80 percent of the spore-formers present,” said Wiedmann. “They grow well in milk — and possibly other foods — at temperatures as low as 43 F, and we can identify Paenibacillus because of their uniquely high galactosidase enzyme activity at 32 C.”
FoodWorld 