Milk undergoes heat treatment -- pasteurisation -- to destroy microorganisms 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.
The organisms are Paenibacillus bacteria, are ubiquitous in nature and cause off-flavours in a variety of foods and curdling in dairy products. The bacteria can the bacteria survive pasteurization and grow under refrigeration conditions.
To read more, see the research brief from Cornell University.