WASHINGTON – A salmonella outbreak that sickened hundreds of people and prompted the recall of hundreds of millions of eggs from a company in Iowa will likely grow, federal health officials said Thursday.

That’s because illnesses occurring after mid-July may not yet be reported, said Dr. Christopher Braden, an epidemiologist with the federal Centers for Disease Control and Prevention.

Almost 2,000 illnesses from the strain of salmonella linked to the eggs were reported from May to July, he said.

No deaths have been reported. The CDC is continuing to receive information from state health departments as people report their illnesses.

The recall of 380 million eggs from Wright County Egg is one of the largest egg recalls in recent history.

Scarborough-based Hannaford Supermarkets said Thursday that it doesn’t sell eggs produced by Wright County Egg.

“We have checked with our suppliers and our stock is safe. We are monitoring the situation,” said Matt Paul, spokesman for Hannaford.

Wright County Egg is owned by Jack DeCoster. He also owns Quality Egg of New England in Turner, formerly called the DeCoster Egg Farm.

Bob Leclerc, compliance manager for Quality Egg, said his farm’s 3.5 million hens consistently test salmonella-free. He said Quality Egg ships throughout New England and the Northeast.

The outbreak could have been prevented if new rules to ensure egg safety had been in place a few months earlier, an FDA spokeswoman said.

The rules, which require producers to do more testing for salmonella and take other precautions, took effect in July. They had languished for more than a decade, after President Clinton first proposed that egg standards be toughened.

Maine has one of the toughest programs in the country to combat salmonella, said State Veterinarian Donald Hoenig. It was developed in response to outbreaks in the 1980s. “Our poultry companies really stepped up to the plate,” he said.

Maine’s regulations are more stringent than the rules announced by the FDA last month, he said. Large-scale egg producers are required to vaccinate and test their hens.

The federal rules require egg producers to control rodents such as mice, which spread salmonella to hens through their feces.

Hinda Mitchell, a spokeswoman for Wright County Egg, said it abided by guidance issued by the United Egg Producers, an industry group.

Those procedures mirror several aspects of the federal egg safety rule.

Illnesses were traced back to eggs produced on three of five farms the Iowa company owns, said Sherri McGarry of the FDA’s Center for Food Safety and Applied Nutrition.

The investigation, which includes sampling, records review and sanitation assessments, is focusing on those three farms.