The U.S. Department of Agriculture does not believe that it will be able to determine the source of the salmonella that sickened at least 19 people and prompted Hannaford Supermarkets last month to issue a chain-wide recall of its store-brand ground beef.

Officials from the USDA’s Food Safety and Inspection Service said Friday that they plan to close the investigation within a week.

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A spokesman says Hannaford disagrees with the USDA that its practices are “high risk,” but does “understand their frustration” with not being able to find the salmonella source. 2011 Associated Press file

The officials said Hannaford’s “high-risk practices” for grinding beef were the barrier in their investigation, although those practices did not break any regulatory requirements and are probably used by other meat retailers.

The practices involve making packages of ground beef by using the trimmings from steaks and roasts that are cut in stores. Hannaford spokesman Michael Norton has said that trimmings constitute about 20 percent of the ground beef in store-brand packages. Most ground beef comes to the company in tubes of coarsely ground meat that is ground again in the stores.

Norton said Hannaford disagrees with the USDA that its practices are “high risk,” but it does “understand their frustration” with being unable to determine the source of the contamination.

Daniel Engeljohn, assistant administrator of the Food Safety and Inspection Service, said it was not always clear from Hannaford’s records when the stores were grinding the trimmings. Investigators found that Hannaford would grind trimmings and tube meat without cleaning the equipment in between, he said, raising the possibility of cross-contamination.

Engeljohn noted that there is a lower sanitary standard for the cuts of meat that are used for trimmings than there is for the ground beef that comes in tubes.

There is no requirement that equipment be cleaned between grinds of meat from different companies, Engeljohn said, but the USDA has told retailers for several years that it recommends it, along with more complete information in grinding logs.

He said the Hannaford investigation gives the USDA “evidence that, industry-wide, there has not been good adoption of best practices.”

Engeljohn said the USDA is turning its recommendations into requirements and expects that to happen by the end of this year.

Hannaford temporarily stopped grinding trimmings on Dec. 15, the day the USDA determined there was a link between a salmonella outbreak and ground beef sold by Hannaford. That’s also the day Hannaford recalled all store-brand ground beef with sell-by dates of Dec. 17 or earlier.

Norton said Friday that the supermarket chain plans to start grinding the trimmings again soon, but will record the source of all meat that is used and will clean the equipment before and after grinding trimmings.

“We’ve implemented changes, and we support formal rule-making for the industry,” he said.

U.S. Rep. Chellie Pingree of Maine, a member of the House Agriculture Committee, said Friday that if the USDA does not develop new rules on its own, she will propose legislation requiring it to do so.

“We definitely need stricter regulations for large retailers so they are required to keep more detailed records on the ground beef they sell, so it’s possible to track down the source of contamination,” she said in a prepared statement.

Staff Writer Leslie Bridgers can be contacted at 791-6364 or at:

lbridgers@pressherald.com