Mexican authorities have reportedly snubbed U.S. Food and Drug Administration (FDA) authorities for the agency's handling the salmonella outbreak.

Enrique Sanchez, director of Mexico's Farm Food Quality Service, said that he is very upset by the FDA investigation and assured that not a single case of salmonella has been reported by the Mexican Health Secretariat. He added that the same product has been consumed in Mexico and no cases of illness had been reported.

Sanchez told a news conference on Thursday that the test sample cited by American officials was taken from a water tank that has not been used for more than two months to irrigate crops. The tank held rain water, he said, which could possibly be contaminated by environmental factors.

On Wednesday, U.S. officials said they had traced the outbreak to irrigation water and peppers grown on a farm in Mexico but also have refused to completely clear tomatoes as carriers of the bacteria.

The FDA has advised consumers to avoid raw serrano and jalapeno peppers from Mexico and any foods that contain them. The salmonella strain has sickened 1,300 people in the United States.