Apples, bananas and cucumbers already have a handy God-made covering, but mankind wanted more. Browned apples and bananas don't look very appetizing. So a thin layer of carnauba wax from the leaves of palm trees did the trick. Other common coatings include starch, carrageenan, gluten, whey and beeswax. Yum.
But there's something unnatural about sliced apples that last 2-3 weeks without turning brown, even with the newer process of coating them with Vitamin C. Coating foods has been done since the 1100s when Chinese merchants shipped oranges to Europe. They used melted fat from hogs. Yum again.
Definitely don't need bacteria to enter our food, but waxed fruit is still not my thing. My grandson agrees. Note the teeth marks above.