Sriracha odor: Why chili pepper particles spread so easily

A plant in Irwindale that makes Sriracha chili sauce has been under fire lately after residents complained of "noxious odors" wafting from the facility. Turns out it came from the chili peppers used to make the sauce. 

Danise Coon can relate.

She is a researcher with the Chili Pepper Institute at New Mexico State University, and she says when she works with the spicy plant, it gets everywhere.

Related: Irwindale to hold public hearing on Sriracha Odor complaints.

“It gets into the air. It gets on your clothes. It gets in your hair," she explained. "It gets in your eyes very easily if you are not wearing protection."

Coon says the reason the pepper plant is so pervasive is that the active ingredient, capsaicin, is microscopic and therefore easily airborne.

In fact, when her students clean particularly spicy pepper varieties, they wear full hazmat suits with respirators to protect their skin and lungs.

Ingenious defense

Like many edible plants, peppers need animals to eat their seeds and pass them elsewhere for the plant spread.

However, the digestive system of mammals completely harms the pepper seed, making them useless when they're eventually left behind.

Coon says peppers likely evolved to carry capsaicin as an ingenious way of preventing this.

That's because capsaicin binds to the same pain receptors in mammals that are triggered by actual fire, resulting in a burning sensation.

This stops most mammals from eating the spicy plant. Birds however are different story.

"Birds don’t have the receptor that binds to capsaicin so they don’t feel the heat at all when they eat super hot chilies,” Coon notes.

Fortunately for pepper plants, birds also don't destroy the seeds as they digest, so when they pass them later on they can grow into healthy plants.

Coon says the pepper's defense mechanism may have backfired a bit since now hot-sauce hungry humans eat more of it than ever before.