Today’s lesson did the opposite of what cooking school should actually do: I lost my appetite. We had a visit from Chef Gregg Drusinsky who teaches ServSafe, a food-safety certification program. And to describe his lecture, I’m going to borrow a word he continually used: “gnarly.”

We spent about four hours (not consecutively, thank God) talking about foodborne illnesses, or diseases that can be transmitted to people through food. Basically your food can be tainted in many ways from an unprofessional food handler (think: that gross nail in your dip) to a burger that’s been sitting out for hours. And if you really want to convince your friends, family or kids to wash their hands, let them know that bacteria like shigella, which is sourced from human feces, can end up in your food because people don’t wash their hands before preparing food.

When we he moved on to talking about fish, the motto was, “Why eat fish if it’s not fresh?” Agreed, but some of us don’t have access to a dock, and have to resort to supermarket fish, which, in Chef Gregg’s words is just “gnarly.” A lot of the fish in supermarkets are farmed, and at these farms, fish are packed on top of each other. Plus, these liquid plantations can be set up next to sewage centers and if you’re buying farmed cod or crab, which are bottom feeders, guess what you’re eating: crap.

I’ll be tested on this information in two weeks. I don’t think I’ll be ordering takeout during my study session.

TIP OF THE DAY: Ask your food handler to change their gloves before they prepare your meal. Gloves can be a false sense of security—make sure your server is just preparing your food while wearing them (not ringing you up, picking his nose, or counting bills while sporting them).