Kitchens, like restrooms require flushing and checking each system. Ice machines can be a source for growing microbes if left to sit. When the ice machine filter removes chlorine from the water before making ice, this becomes a common issue even for normal operating conditions. Dried out floor drain traps can create odors. Usually, flushing a volume of water down them will seal them off. However, if odors continue, there are both mechanical and chemical trap seal options that will eliminate the problem.
When it comes to barriers, it may seem obvious to think about gloves and masks, but physical space can be a barrier as well. Consider the touch-less commercial kitchen faucet. It creates a space, an air-gap if you will, between usage, eliminating cross contamination.