Dangerous Greens

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Astronauts: Beware of the lettuce.

That’s because while a 2020 study found that lettuce grown in space was as safe and nutritious as the leafy greens found on Earth, new research has shown that space-grown salad could make space explorers very sick, according to Science Alert.

In their paper, researchers from the University of Delaware conducted a series of tests on plants grown in simulated microgravity.

To replicate the space environment, they used a device called a clinostat to perform some rotation tricks in the lab. This put the lettuce plants into a similar state as microgravity.

The team then added the Salmonella enterica bacteria to the leaves and noticed something peculiar: The plants’ stomata pores – which keep attackers out – opened up and allowed the pathogens to go inside.

Even adding helpful bacteria to combat the invaders didn’t help the plants, the researchers noted.

While more research is needed on the phenomenon, they theorized that the microgravity state disabled the chemical reactions that the lettuce would normally use to keep itself safe.

“In effect, the plant would not know which way was up or down,” said lead author Noah Totsline. “We were kind of confusing their response to gravity.”

The authors hope that further studies can come up with innovations to make food safer in space and potential future missions.

“You don’t want the whole mission to fail just because of a food safety outbreak,” noted co-author Harsh Bais.