Science

Listeria, not so much, but choosing reputable sources of milk products can guard against it.

Washing fresh fruits, vegetables and meat is the single most effective way to reduce pathogens. Even washing fruits from which you peel the skin (such as bananas) is recommended.

Ensuring you cook to the temperature at which pathogens are killed, especially for pork and chicken. Maintain the temperature for a few minutes to ensure complete eradication.

Maintaining the food at a safe temperature after serving (Ensure egg products are kept cold all the way through especially in summer; don't leave them in the sun).

Maintain awareness of which implements were used on uncooked meats, and which are used to serve cooked meats.

Color code implements for Vegan preparations (Red for meat, yellow or orange for fish, and Green for veggies is obvious).