The Produce News reports that the health department of the government of Mexico, in an official memorandum dated Oct. 9, announced an immediate halt on the importation of all fresh lettuce from the United States including bulk lettuce and fresh salads containing lettuce, an action that baffled many in the U.S. produce industry.

The memo, which was written in Spanish and which originated from office of the Federal Commission for the Protection against Sanitary Risks, noted that "this Sanitary Authority has knowledge" that "irrigation water used in the lettuce production fields in the Salinas Valley of California is contaminated with the bacteria E. coli." The memo stated that the ban was a precaution intended to minimize the risk to public health while "the source of contamination" was being identified.