Tracing Food-Borne Illnesses Through Grocery Loyalty Cards

By: Michele Wolfson

There have been food-borne illnesses this year that have killed over two-dozen people and have made about double that amount extremely ill. Many more may have been afflicted if it weren't for food safety officials finding value in shopper loyalty cards. These officials are faced with food-borne illness outbreaks across communities and states that seem to have no obvious links- until now.

Food purchases can be traced through loyalty cards and provide an accurate record of everything shoppers bought at the store going back for years. New York State and local health officials noticed an increased number of salmonella cases and started conducting routine interviews. The outbreak of pine nuts contaminated with salmonella in Wegmans, a big chain supermarket, was discovered through loyalty shopper card records.

There has been a controversy with breech of privacy due to these kinds of investigations. Stores have the right to refuse to share their records with health officials, but many believe it is necessary in order to provide a valuable trail of evidence that can save lives. Given permission by patients to check their shopper club card data, officials found "a lot of these people were buying bulk Turkish pine nuts," or foods that contained them, says Casey Barton Behravesh, with the Centers for Disease Control and Prevention.

Other recent cases include:

  • An outbreak of E. coli that sickened 33 people and led to 15 hospitalizations in five Western states in 2010 was quickly traced to raw milk Gouda cheese produced by Bravo Farms in Traver, Calif., using Costco purchasing data.
  • A bewildering outbreak of salmonella that sickened 272 people in 44 states in 2009 was finally cracked when health officials examined shopper records from Costco and saw that almost everyone who had gotten sick had purchased salami from Daniele Inc. Testing showed it was not the sausage but the black and red pepper it was coated in that carried the bacteria.

The shopper loyalty cards also can help public health workers when consumers misremember what they consumed. "One person swore she didn't eat cantaloupe, she only ate honeydew melons," says William Keene, a senior epidemiologist with Oregon Public Health Services. "When we pulled her records, we found that she only bought cantaloupe, not honeydew. When we showed her that, she said 'Oh, I guess I did eat cantaloupe.'" Apparently these loyalty cards are useful for more than just a discount.

Photo: joelogon 

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