Elsewhere in Ca Mau, Nguyen Van Hoang packs shrimp headed for the U.S. in dirty plastic tubs. He covers them in ice made with tap water that the Vietnamese Health Ministry says should be boiled before drinking because of the risk of contamination with bacteria. Vietnam ships 100 million pounds of shrimp a year to the U.S. That’s almost 8 percent of the shrimp Americans eat.

Using ice made from tap water in Vietnam is dangerous because it can spread bacteria to the shrimp, microbiologist Mansour Samadpour says, Bloomberg Markets magazine reports in its November issue.