As the official toll in the listeria-in-cantaloupe outbreak rose to 13 dead and 72 sick in 18 states, a major retailer said cantaloupe growers need to do more to prevent outbreaks of foodborne disease.

“I don’t think the cantaloupe industry can continue on doing the very same thing and expecting a different result,” said Craig Wilson, the head of food safety for Costco, the Seattle-based warehouse retailer, which is regarded as a leader in requiring food safety measures from its suppliers. “It’s time for companies to get more aggressive. If they know this is going to happen, let’s step up and not let it happen.”

William Neuman of the New York Times reports federal officials on Tuesday that there had been at least 19 previous outbreaks involving more than 1,000 illnesses and three deaths resulting from cantaloupe consumption since 1984. We count at least 36 outbreaks.

Wilson further said Costco would consider setting standards for how melons are grown and how they are cleaned and handled after they are picked. He said the company would most likely require that suppliers test melons for pathogens before shipping them to Costco.

He called on the industry to finance research into the best way to wash or clean cantaloupes to remove contaminants.

Dr. Margaret Hamburg, commissioner of the Food and Drug Administration, said that investigators had yet to determine how the melons became contaminated.

Trevor V. Suslow, an extension specialist at the University of California, Davis, who has done industry-financed research into food safety and cantaloupes, said that the fruit’s rough skin made it more susceptible to harboring unwanted bacteria.

“You have these tremendous hiding places, if you will, nooks and crannies, lots of areas for microbes to get in and attach and hide,” Dr. Suslow said.
It is best to keep cantaloupes dry to reduce the possibility that bacteria will grow on them, he said. In California, growers typically do not immerse melons in water to wash them and use chilled air to cool them.

In other regions, he said, cantaloupes are often washed in a large tank or with a water spray and are cooled with sprays of cold water as well. Those techniques may be more likely to spread bacteria.

Stephen F. Patricio, a melon shipper who is the chairman of the California Cantaloupe Advisory Board, a trade group, said that sales were plummeting, even though only melons from the farm in Colorado were implicated.

“The entire melon category needs to look at the best practices and research that’s been done by the California industry and others to best analyze their own risks,” Mr. Patricio said. “Or we’re all going to continue to suffer.”