In the microscopic level you can use non-toxic chemicals etc and you can aslo keep the food in desirable temperature inorder to prevent it from being rotten, incase of some food get contaminated you can just not use it because it can make you sick or if it only partly contaminated, then you can use the uncontaminated part of it and not use the other part.
a turkey sandwich has more protein unlike the potato chips. a turkey sandwich would fill your stomach better than potato chips. a turkey sandwich is heathier than potato chips for multiple reasons including sodium, and carbs.
therefore the turkey sandwich would be a better choice.