In order to prevent food contamination, a food handler must:

While all the options listed relate to general kitchen operations,frequent handwashingis the single most important practice a food handler can perform to prevent the spread of foodborne illness. According to the CDC and ServSafe, human hands are the primary vehicle for transferring pathogens likeNorovirus,Hepatitis A, andStaphylococcus aureusto food and food-contact surfaces. Handwashing is a "preventative" measure that addresses the root cause of many outbreaks: poor personal hygiene.

The FDA Food Code is very specific about handwashing: it must take at least 20 seconds, with at least 10–15 seconds of vigorous scrubbing. It must be done in a dedicated handwashing sink—never in a prep sink or three-compartment sink. Food handlers must wash their hands at critical junctures: after using the restroom, after touching their face or hair, after handling raw meat, after coughing or sneezing, and before putting on gloves. Option B is incorrect because the safe holding temperature is $41^{\circ}F$ or lower, not $45^{\circ}F$. Option C is incorrect because frequently used surfaces must be sanitized every 4 hours, not 5. Option D is a general task, but it doesn't match the critical preventative impact of hand hygiene. By making handwashing a mandatory, frequent habit, the manager ensures that the most common path of contamination is blocked. This is often described as the "gold standard" of food safety because it protects the food throughout the entire "Flow of Food," from preparation to the final service to the customer.