Final answer:
Plastic or metal mesh covers over light bulbs in food prep areas primarily reduce the risk of contamination by preventing glass shards from entering food if a bulb breaks.
Step-by-step explanation:
Placing plastic or metal mesh covers over light bulbs in food prep areas reduces the risk of contamination. These covers are designed to protect food from potential contaminants that could result from glass shards if a bulb breaks. Such a safety measure is important in the food service industry where hygiene and food safety regulations strictly prohibit contaminants in food preparation areas. These covers do not significantly reduce energy consumption, heat emission, or light intensity; rather, they are a precaution against physical contaminants.