A major egg recall has been expanded to 380 million eggs because of a salmonella outbreak that has sickened hundreds of people in four states. Federal officials said the outbreak could have been avoided if the producer had complied with new safety rules before they went into effect last month.

Wright County Egg of Iowa recalled the tainted eggs packaged nationwide under the names Lucerne, Albertson, Mountain Dairy, Ralph's, Boomsma's, Sunshine, Hillandale, Trafficanda, Farm Fresh, Shoreland, Lund, Dutch Farms and Kemp. The eggs were distributed in 17 states. No natural or organic eggs have been included in the recall.

The U.S. Food and Drug Administration is investigating sanitation conditions at the egg processing facility, including rodent control, said Sherri McGarry, director of public health and biostatistics at the FDA’s Center for Food Safety and Applied Nutrition.

McGarry said at a press conference on Aug. 19 that measures could have been taken to prevent the outbreak if new rules had been in place before they took effect July 9.

Officials did not say what rules would have helped. The rules include requirements that farms test eggs routinely for salmonella and take precautions against hens becoming infected with the bacteria. Eggs are infected with salmonella through a hen’s ovaries.

In a statement, Wright County Egg said it was fully cooperating with the FDA’s investigation.

Gail Damerow, the author of several books about raising chickens, including A Guide to Raising Chickens: Care, Feeding, Facilities (Storey Books, 1995), said Wright County Egg eggs are packaged and repackaged by different distributors. Such a centralized food production system involves more handling, longer travel times and the possibility of different refrigeration temperatures, she said.

“Eggs from natural and organic producers usually take a more direct route to the customer,” Damerow said. “When customers know where their food comes from, producers have a greater incentive to provide safe products.”

In addition, she said that hens are overcrowded and overstressed in large industrial operations, leading to lower resistance to disease, and that the routine use of antibiotics contributes to more resistant strains of bacteria.

“Natural and organic producers rely on proper management practices rather than on the improper use of antiobiotics (and) generally follow more humane, less stress-inducing practices,” Damerow said.