Final answer:
Food can become contaminated through cross-contamination, poor hygiene, and improper temperature control.
Step-by-step explanation:
Cross-contamination is a major way that food becomes contaminated. This occurs when microbes are transferred from one food to another. For example, if an employee uses a cutting board to prepare raw meat and then uses the same cutting board to prepare sandwiches without properly cleaning it in between, the sandwiches can become contaminated with bacteria from the raw meat.
Another way food can become contaminated is through poor hygiene. If the employee does not wash their hands properly before preparing the sandwiches, they can transfer bacteria from their hands to the food.
Lastly, improper temperature control can lead to food contamination. If the deli employee does not store the food at the correct temperature, bacteria can multiply and cause contamination.