Costco’s Craig Wilson still recalls the Salmonella outbreak in almonds in 2004. “It started in Oregon, and ultimately it moved to almost every state,” he said. More than 30 cases in 12 states and one Canadian province were linked to the same Salmonella isolate.
Epidemiologists tracking the five initial cases of Salmonella in the outbreak had determined that all had made purchases at Costco warehouse stores. “They came to us and said, ‘It looks like the source of the pathogen could have been raw almonds, or a couple of other different items. Could you let us know who bought what and when they bought it?’” recalled Wilson, Costco’s food safety director. “The members had given them their Costco membership numbers, so we were able to use those to track their purchases and nail down the organism.”
On May 18, 2004, Paramount announced a nationwide recall of all raw almonds sold under the Kirkland Signature, Trader Joe’s, and Sunkist labels. Costco mailed 1,107,552 letters to members who had purchased the recalled almonds. “This all led to the new almond pasteurization law,” Wilson said. “We figured out what the problem was and worked with the California Almond Board and almond growers in a process that kind of reshaped the almond industry.”
That was nearly eight years ago, but even then, using member purchasing information to contribute to epidemiological investigations of foodborne illness outbreaks and alert consumers about recalls of foods that they had specifically purchased was nothing new at Costco.
“We’ve been doing this for at least a dozen years,” Wilson said. “It makes perfect sense. When you’re an epidemiologist and you’ve got an outbreak of illness and you talk to 20 people and they all think they ate the walnuts, the ground beef, the tangerines, the bagged salad, and they all shopped at different places, what do you do? Often, state epidemiologists will call us and say, ‘We have an outbreak of X illness in this area, and we think we have it narrowed down to these five food items with these five people, and three of them are Costco members. Here are their numbers—can you see what they purchased?’ Of course we’ll do that, always with our members’ permission. It’s worked just great. We’ve cracked some really big cases.”
A nationwide recall of raw almonds in 2004 led to the new almond pasteurization law — thanks in large part to Costco’s use of member information to track the outbreak and identify the organism responsible.
A November 2011 article in USA Today highlighted the utility of shopper loyalty cards in tracing foodborne illness outbreaks—but it’s worth noting that most of the cases described in the USA Today article involved Costco-facilitated investigations, including a 2010 outbreak of E. coli 0157:H7 in raw milk Gouda cheese and the notorious 2009 Salmonella Montevideo outbreak ultimately traced to black and red pepper used to coat sausages. USA Today also cited Wegman’s as helping out in one other case it described, and Kroger is also known for utilizing its shopper loyalty card data to facilitate outbreak investigations.
But beyond Costco—which is a membership store, so everyone has a card—and a few others like Kroger and Wegman’s, it doesn’t seem that grocery store chains have broadly taken up the use of these ubiquitous little plastic cards to help find out what may have made some of their customers sick, or to keep them from getting sick in the first place.
Several grocery chains contacted by Food Quality magazine declined to comment for this story. A spokesperson for SuperValu said that he could not comment because the national chain, which has more than 4,000 stores under a dozen names in almost every state, was “in the early stages of implementation” of a plan to leverage loyalty card data for foodborne illness outbreak investigation.