Celebrity chef Robert Irvine shares the biggest red flag he looks for when dining out in any restaurant

• Robert Irvine is a Food Network star and celebrity chef.
• While at South Beach Wine and Food Festival, he spoke with Insider about dining out.

Celebrity chef Robert Irvine has been helping struggling restaurants turn around their businesses for years on his Food Network show, "Restaurant: Impossible." So it's no surprise that when he goes out to eat, there are certain things he's always looking out for to tell him whether it's somewhere worth dining.

In an interview with Insider around his appearance at the South Beach Wine and Food Festival, Irvine shared the No. 1 marker he pays attention to, which isn't even directly related to the food: the bathrooms.

"Well, the first thing I look for is, are the bathrooms clean?" he said. Irvine said this is his top red flag "because if the bathrooms are clean, the kitchen's clean, everything else is clean."

He told Insider the bathrooms are a great indicator of how the rest of the establishment is kept and cared for. And if it's a dirty restroom, that might mean there are less-than-stellar cleanliness standards being set for the eatery as a whole.

"We look at signs that are amenable to us," Irvine said, explaining that since he keeps his bathrooms, kitchen, and the rest of his own home clean, that's an easy thing for him to examine elsewhere. "So that's what I look for when I go to a restaurant."

The Food Network star and military philanthropist said he also tries to observe the servers to see if they're happy while on the job.

But regardless of the cuisine, the type of dining establishment, or where on the map you're visiting, the chef said the biggest favor you can do for yourself if you're questioning whether to eat somewhere is to take a trip to the bathroom first.