Food and Drug Administration said in a letter that was written on January 27, but released today, that Kellogg Co. must fix sanitation violations at an Atlanta plant after the contamination of Eggo buttermilk waffles with Listeria bacteria. These bacteria can contaminate food that can result in mild illness or sometimes life-threatening, illness called invasive listeriosis.

The Food and Drug Administration said that the October 2009 inspection of the Atlanta plant found bacterial contamination and sanitation violations such as improper handling of waste and food, and inadequately sterile equipments that had been cleaned with high-pressure water that splashed near raw ingredients.

It is essential for Kellogg to identify the regions where Listeria can grow and survive. It should take the necessary actions to control the organism, said the Food and Drug Administration.

"We have made a variety of enhancements in our facility, and have fully addressed all of the observations in the letter", said Kellogg spokesman Kris Charles in an email.

In the New York Stock Exchange shares of Kellogg rose 18 cents to $52.52.