[merryocha]

One thing I rarely see discussed is the possibility of contaminants like machine grease, spray lubricants, and dust getting into food. When the process for making food is automated, it seems much more likely to me that some of the moving parts in the process end up getting coated with small amounts of machine grease or lubricants. Maybe a moving machine part was sticking, so a technician used some spray lubricant on it, some of which found its way to the conveyor belt that was transporting the food to the next stage of the process. Maybe a metal part that is used in the process was coated in some kind of oil to protect it during storage. Someone may install it without cleaning it off with a solvent. Maybe something is being stored in an open-air vat, and work is being done nearby that generates dust. The more processed a food is, the more opportunities there are for contaminants to find their way into the food.

I think of these things because I worked in a kitchen that made dough, and our dough mixer always needed to be lubricated. I once found grease that had dripped from above into the mixing bowl. Luckily I am someone who takes such things seriously, but there are a lot of careless people out there. Even if you wipe off grease, an invisible trace amount will remain on the surface unless you clean it with a solvent. I also worked in a warehouse that stored machine parts used in food packaging equipment. There was drywall work being done at the time and the whole place was coated in gypsum dust. I remember handling "food grade" lubricant and looking up its safety data sheet (SDS) out of curiosity, and my takeaway from reading it was that it's still probably not something you would want to eat.