FDA reports pull back curtain on Salmonella risk at egg farms

Sep 1, 2010 (CIDRAP News) – Reports of mice, other pests, and manure piles in the US Food and Drug Administration 's (FDA's) initial egg farm investigation findings this week are still reverberating among the public, the industry, and longtime observers of poultry and egg production.

Though the FDA has had some authority to regulate egg farms, the launch of new egg safety rules in July for large producers imposed more stringent and specific Salmonella Enteritidis (SE) prevention targets. The national SE outbreak and recall of about 550 million eggs from two large Iowa producers prompted the FDA's first extensive egg farm inspection under the new rules, which led to long lists of findings contained in the agency's Form 483 inspection reports released on Aug 30.

David A. Halvorson, DVM, an avian health expert who is retired from the University of Minnesota, has spent more than 40 years visiting poultry houses in most US states and Canadian provinces and in Mexico, South America, Europe, and Asia. He said he was still analyzing the 483 inspection reports and was not in a position to support or criticize the egg farmers or the FDA findings. However, he offered observations that relate to some of the SE risk factors found on the farm. In general, he suggested that some of the FDA's findings are not as surprising as they might seem at first glance.

So far the FDA has announced some positive SE lab findings in environmental samples, feed produced at one of Wright County Egg's farms, and egg wash water from a Hillandale Farms facility, but it hasn't announced any positive or negative findings from tests on the eggs. FDA spokeswoman Pat El-Hinnawy told CIDRAP News today it has collected hundreds of samples from Wright County Egg and Hillandale Farms, and lab results on most of them are still pending.

Mice tough to control
Halvorson said mice play an important role in SE ecology, so mouse control is critical in an egg production operation. Feces from SE-infected mice can contaminate poultry feed, transmitting the disease to chickens. In the 483 reports, federal investigators said they found live mice in some of the poultry barns and evidence of unsealed rodent holes in some others. A farm that has a million hens consumes about 250,000 pounds of feed each day, he said. "Even a very small amount of spilled feed attracts pests. So far, eradicating pests from a farm has not been possible, so a constant effort to control them is necessary."

Observing 31 mice over a period of 18 days in perhaps 50 or 60 poultry houses might or might not be considered excessive, Halvorson said.

Wild birds theoretically may play a role in SE transmission, he said. The inspection reports detailed evidence of wild birds in some of the poultry barns and around the feed mill. Halvorson said wild birds can enter poultry facilities when doors are opened to allow tractors to enter. "So a wild bird in a poultry house, while not desired for many reasons, does happen."

Flies also may play some role in spreading SE, but a significant role has not been established, he said. In the 483 reports, FDA investigators found numerous live and dead flies in the poultry barns, including around the egg conveyors. Halvorson said a farm that has 1 million hens typically produces about 250,000 pounds of manure each day.

"Manure is an excellent substrate for fly reproduction, so flies, and also maggots, are a fact of life on a farm that produces animals," he said, adding that it would be unusual not to find flies on an animal farm, and the presence of flies means maggots are nearby.

The 483 reports also described several other biosecurity lapses, such as gaps in walls and doors, holes in feed ingredient bins, and access doors that were pushed open from the weight of accumulating manure.

Handling large volumes of manure usually requires either tractors to enter the barns through large doors or conveyors to penetrate barn walls to move manure out, Halvorson said. It's not unusual to see gaps around doors and conveyors, he said.

Clothes-changing rule questioned
Inspectors said they observed instances of employees not changing or wearing protective clothing when moving from laying house to laying house, according to the 483 reports. Halvorson said in his many years of visiting poultry houses, he doesn't recall seeing workers routinely change clothing when going from one house to the next, though he said changing clothes when going between adult chickens and chicks is a common practice.

On the day the FDA released its findings, Halvorson said the egg safety inspections break new ground for the agency's inspectors and seem to herald a shift away from assuring that farms are free from SE and more toward making sure firms are complying with SE prevention plans.

He said requirements such as changing clothes between barns connected by an egg conveyor and forbidding employees to own pet birds are inexplicable and indicate a lack of understanding of farm operations and SE biosecurity, respectively. He added that the FDA would help egg producers as well as consumers by focusing prevention efforts on known successful mitigation strategies: SE-negative chicks, rodent control, an SE-negative environment, and vaccination.

Though Iowa, the nation's biggest egg producer, is among states that do not have their own egg quality assurance programs for farms, a spokeswoman for Wright County Egg has said the company was in compliance with the new federal rules as well as an industry-based food safety program that addresses cleaning and disinfection of poultry houses, pest control, proper egg washing, biosecurity, and refrigeration from packing through delivery.

In the wake of the inspection reports, both Wright County Egg and Hillandale Farms have issued statements saying they're fixing the problems reported by the FDA inspectors, the Des Moines Register reported yesterday.

FDA officials said that over the next 15 months investigators will inspect about 600 of the nation's largest egg producers, starting in September with the facilities that are at highest risk.

In other developments, FDA inspectors returned to the two farms yesterday, the Associated Press (AP) reported today. An FDA spokeswoman and a federal attorney who covers Iowa confirmed that the agents were at the sites but did not reveal why they were there, according to the AP report.

At an Aug 30 media briefing about the 483 reports, FDA officials didn't say what their next steps would be in response to the egg safety violations they found. The options could include seizure, injunction, or even criminal prosecution.

See also:

Aug 30 CIDRAP News story "FDA reports show multiple biosecurity gaps at two egg farms"

Aug 31 Des Moines Register story

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