A food-poisoning expert reveals 5 things he never orders at restaurants - and it's not what you'd expect

Cleanliness of ice and ice cream machines can cause huge problems when workers aren't following safety guidelines. There's a grossness factor of finding mold in soft-serve ice cream machines — but there are also real risks.

"There have been a number of cases linked to listeria, where listeria will get into the inner workings of these ice cream machines and kill people," Marler said.

Marler agrees with known-germaphobe President Trump on at least one thing: well-cooked meat is the way to go.

"Skip the medium hamburger and get it well done, and just add a little ketchup like the president," he said.

According to the expert, meat needs to be cooked to 160 degrees throughout to kill bacteria that could cause E. coli or salmonella.

"I never eat a buffet," Marler said. "I'll order off the menu."

Buffets have a heightened risk of exposure to the lines of people who might touch or sneeze on food, contaminating the dish for anyone else. Then, there is the temperature issue, as dishes are better able to host bacteria when kept at room temperature.

In general, Marler says people can best avoid food poisoning by simply eating food handled by as few people are possible and only eating at restaurants with strict food safety practices.

While chain restaurants tend to have strict safety policies, if they serve food from suppliers that got contaminated at some point along the supply chair, there is little they can do. And, those risks are exacerbated in the cases of food that is being imported from a significant geographical distance.

"You can get Hepatitis from scallops from the Philippines, but you probably shouldn't be eating scallops from the Philippines," Marler said. "You can get Hepatitis A from strawberries from Egypt, but you probably shouldn't be getting strawberries from Egypt."