It's only a thing in New York, California, Texas, Illinois, and Washington, D.C. for now. 

yelp app can help with food poisoning
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What do you look for in a restaurant? Good food, pleasant service, maybe comfortable seating, and hopefully it's clean, too. Many cities have adopted a policy of assigning letter grades to restaurants, which help consumers determine which eateries have passed health inspections. Now, Yelp is adding a similar feature to its restaurant listings by providing so-called hygiene scores.

As CNN reports, though the feature is currently only available for restaurants in New York, California, Texas, Illinois, and Washington, D.C., Yelp plans to continue the roll-out through the year, eventually providing hygiene scores for 750,000 restaurants in cities nationwide.

Yelp hopes that clearly, openly posting the info will help customers—who usually have to physically go to the restaurant and look for a letter grade taped in a window—weed out spots whose cleaning standards aren't up to par.

After all, it would be incredibly frustrating to find a restaurant in your neighborhood with seemingly-good reviews, only to get there and discover that it has a C-grade from the health inspector.

To get grades for restaurants in its network, Yelp began working with local governments in 2013 to create a database called the Local Inspector Value-Entry Specification, a platform where cities can post the health scores of local eateries. Not every city provided information, though, so Yelp turned to another startup (called HDScores), which aggregates restaurant inspection data.

The new system does help diners make informed decisions (and might even encourage restaurants to clean more) but there is a negative side: Health codes vary from city to city, meaning that a B-grade doesn’t mean the same thing in New York City as it does in Washington, D.C., and the health inspectors who give the grades aren’t always consistent.

Consumers should, as always, use their best judgment when picking a dining spot, keeping in mind that a low hygiene score doesn’t automatically mean there was a mouse in the toaster. Of course, when it comes to your health, you might not want to give a restaurant the benefit of the doubt—but it’s probably best to not take all the information you find on the internet at face value, either.