Microbiological aspects in whey powder production: What is the relevance of enterotoxigenic Staphylococcus aureus?

Whey, a greenish-yellow liquid resulting from curd separation in cheese manufacturing, was historically considered economically insignificant in the dairy industry and often discarded into the environment without proper oversight. However, recognizing its high nutritional value, whey has become a valuable ingredient in the food industry. Unprocessed whey (raw material) is highly susceptible to contamination, as it can serve as a substrate for the multiplication of a range of microorganisms, including spoilage, spore forming, pathogenic and toxin producing bacteria, particularly if stored at inappropriate temperatures. Staphylococcus aureus is one of these potential pathogenic bacteria often associated to dairy, that can also persist in the environment through biofilm formation and, once reaching the food matrix, can grow and produce enterotoxins. During the processing of whey powder production, there are points where S. aureus might find its way into the final product. Here we demonstrate critical contamination steps, and we highlight the need for more research to assess the microbiological integrity of whey powder, especially in Brazil, where its production has been growing in recent years. Considering the increasing use of whey powder as an ingredient for various formulations, continuous surveillance for the presence of spoilage microbiota and potentially pathogens, including S. aureus and associated enterotoxins is indispensable to prevent food poisoning outbreaks.