Samples of Salmonella bacteria have been detected by inspectors of the U.S. Food and Drug Administration at a farm in Mexico that produces serrano peppers, officials announced on Wednesday. Furthermore, the samples matched the strain that has affected over 1,300 people across the United States and parts of Canada, David Acheson, FDA associate commissioner for food protection, told a congressional hearing, as reported by Reuters.

As cited by the same source, FDA spokeswoman Stephanie Kwisnek authenticated the fact that Salmonella Saintpaul had been found “in a sample of serrano peppers and a sample of water from a farm in Mexico,” in spite of the fact that the Mexican government criticized the FDA examinations and explained that the sample had been taken from stagnant water in a reservoir which contained rainwater, and not from the water supplies used to irrigate peppers.

The Mexican Embassy in Washington previously said the government had taken the preventive measures of canceling exports of produce coming from the company believed to be the source of the outbreak.

On Monday, Colorado health officials announced they had discovered a Salmonella-tainted jalapeno pepper in the house of someone that got sick in the outbreak. Furthermore, a contaminated pepper was found in a shipment of jalapenos from Mexico last week.

Although investigators had initially focused on tomatoes as a potential cause, regulators retracted their warning on the produces last week. Even though they did not lift the warning because tomatoes were cleared from suspicion, any of the contaminated products would have rotted and been disposed of up to then.

Salmonella poisoning, which causes diarrhea, fever and abdominal cramps, is very frequent, with 40,000 cases and 400 deaths each year in the United States alone.