Many people are afraid of getting the flu from their food sources, but really it is very unlikely for you to contract the flu from the things you eat. But during flu season you should keep a mindful eye on the foods you are preparing.
Foodborne illnesses is due largely in part to cross contamination of cooked and uncooked food. Ways to keep you safe include; washing your hands before and after dealing with food, washing your kitchen, dishes and utensils with hot water, cooking and serving food on clean plates and dishes, and constantly washing your cutting boards and countertops before and after use.
Also, foodborne illnesses are also caused by bacteria. Bacteria is capable of attacking your food in under two hours if kept at room temperature. So when preparing food, make sure you defrost and marinate foods in the refrigerator, not the counter. After two hours of being out at room temperature -- you should discard the food item.