Final answer:
A foodservice manager can continue serving a beef stir-fry without heat for up to two hours according to food safety guidelines. After this period, the food should be discarded to prevent bacterial growth and potential foodborne illness.
Step-by-step explanation:
According to food safety guidelines, if a foodservice manager loses their heat source for hot-holding food, they can utilize a written time as a public health control procedure to continue serving the beef stir-fry without heat for a limited period. This time period is typically up to two hours. Once this two-hour limit has been reached, the food must be discarded to prevent the risk of bacterial growth and potential foodborne illness, as bacteria multiply most rapidly between temperatures of 40 and 140 degrees Fahrenheit. Serving food that has been in the "danger zone" for temperatures longer than two hours puts consumers at risk.