A Mexican chef and over 100,000 YouTube viewers learned a very important lesson in the kitchen: Not all cheeses are created equal. In an effort to make a statement about processed foods, Jose Raul Reyes conducted an experiment to prove whether processed cheese slices are made with real cheese. The chef filmed himself while he put the packaged cheese directly over the hot flame, and what happened next is not what you would expect.

Rather than melt, the cheese in the video, sold by discount chain Aurrera, merely blackened and became charred — just like plastic would. “I tried it out after hearing from a friend of mine that these cheese slices are not real cheese and don’t melt,” Reyes says. “I felt like I was being ripped off, so I videoed it and stuck it on YouTube, and was surprised about the reaction.”

Some of the comments included, “Why doesn't the health Ministry ban something like this, which clearly isn't cheese?” While another wrote: “If anybody wants to know why cancer is on the increase, look no further.” The question is, Will Reyes's video deter cheddar enthusiasts from buying processed cheese?

A similar experiment was done in the U.S. with several packages of processed cheese, including Kraft. In a video posted by jewls73184, she shows exactly what happens when you hold a lighter to a piece of this “cheese.” The YouTube user attempted to heat a single slice of Kraft cheese using a lighter, only to discover it did not melt.

This prompted Kraft to release their own YouTube video explaining why their cheese doesn’t melt at high temperatures. The company stressed their cheese was perfectly healthy to eat and contained only real cheese and natural product additives. However, they do use emulsifiers, which prevents cheese from melting at high temperatures, to bind the proteins and fat.

Processed cheese is one of the leading cheese varieties in the world. They typically cost less than natural cheeses and have a longer shelf-life, but just don’t expect them to actually be made with real cheese. Dish out a couple of more dollars when you can on the real thing, and remember to say “cheese!”