The laboratory reports a positive coliform test that exceeds permissible limits on a bottle of pasteurized milk. What does this indicate?

A positive coliform test that exceeds permissible limits on a bottle of pasteurized milk indicates a failure in the pasteurization process or a subsequent contamination of the milk. Coliform bacteria are often associated with fecal contamination and indicate that harmful pathogens may be present, which raises serious safety concerns regarding the product.

When considering improper bactericidal treatment of the equipment, it highlights that the equipment used in the processing or handling may not have been adequately sanitized, allowing for the survival of bacteria even after pasteurization. Pasteurization is designed to eliminate harmful microorganisms, so the detection of coliforms suggests that there may have been lapses in the sanitation protocols or processes employed in the production of the milk.

Other options like virucidal treatment and a contaminated water supply are less directly related to the detection of coliforms in pasteurized milk. While water quality can affect food safety, in this scenario, the focus is more on the equipment used during the milk's processing. A contaminated food supply could be a broader implication, but the findings here specifically point toward an issue with the bactericidal aspects of the equipment rather than an external source of contamination like water or inherent contamination from the food supply itself.