5. Cheese
You want to believe that cheese is vegetarian, right? No animals killed in the production? Well, that’s not always the case. Most cheeses contain a compound called rennet, which is traditionally found in the stomach of nursing calves.
It may not be impossible to find cheese that you can eat without turning your stomach. Approximately 80% of rennet used today has been genetically engineered by inserting cow DNA into certain bacteria, fungi, and yeasts.