Why You Should Think Twice About Saving Costco's Caesar Dressing

Science is a harsh mistress. For instance, Difference Between says if you have two atoms of hydrogen bonded to one atom of oxygen, you get water. However, if you have two atoms of hydrogen conjoined with two atoms of oxygen, you get another clear fluid, hydrogen peroxide. While water nourishes your body and keeps you alive, CNN explains that hydrogen peroxide can make you intensely ill.

Though we don't generally think of cooking as being chemistry, ECPI University says that chefs use chemistry on a daily basis. It's important that science and chemistry are some of the secrets chefs learn at culinary school. This helps would-be kitchen mavens understand how to make food and why food is prepared in a particular way. As with water and hydrogen peroxide, the chemistry used in cooking can either enhance food or turn it into something disastrous.

One Reddit user ended up getting a mildly disgusting lesson in chemical reactions when they suddenly found their Caesar dressing from Costco was bubbling up like the world's creamiest soft drink. Which sounds delicious should you be among those who like anchovy paste in their soda. Tragically, that's very few people.

It's not always clear which foods need to be refrigerated, and which do not. According to the USDA, unopened salad dressing can be kept in the pantry. This may not be true of Primal Kitchen's Caesar dressing, however. A short video made by a Reddit user shows a bottle of Primal Kitchen Caesar dressing that is oozing creaminess all over the counter. The poster didn't seem to know what was happening, but the commenters certainly had some theories. "It fermented," said one. "Natural yeast ate the sugar released CO2 and boom dressing soda."

This could possibly be the case. According to MasterClass, fermentation can occur in a substance with microorganisms — yeast and bacteria — and carbohydrates like sugars, which can release carbon dioxide. Another pointed out that the issue could be with the seal on the bottle. "These primal kitchen products almost universally have a bad seal," complained a visitor to the thread. "They're going to kill someone and or have a massive recall someday," they wrote.

Whatever the cause, the Redditor said the dressing was sealed and in the pantry, which means anyone buying Primal Kitchen Caesar dressing would be wise to keep it cool, as temperatures under 40 degrees limit the growth of bacteria, per Michigan State University.