The often-missed Bill Keene was quoted in 2013 about using loyalty cards in an outbreak investigation ‘We rely on people’s memories, which are quite fallible, and on our interviews, which are quite fallible; Shopper club cards are a good source of finding out what people ate.’

Cards can be used to connect with members who purchased specific products if those products are part of an outbreak or recall – a tool to overcome the poor memories.

Lots of data is collected by retailers with every swipe of a loyalty or membership card: date, product, lot, location. CDC reported that the cards aided in an investigation into a 2009 outbreak of Salmonella montevideo linked to pepper (which was used as an ingredient in multiple foods).

And this frozen cherry/berry hepatitis A outbreak at a Canadian membership retailer in 2013 (sounds familiar).

It’s not failsafe though; folks, who, according to PHAC, sampled frozen berry dishes at Canadian Costco outlets recently, may not know they might have been exposed to hepatitis A.

CBC says go ahead and get an IgG shot at Costco quickly. Because it might not work for too long (based on the window of exposure).

Eastern Health’s chief medical officer David Allison is warning people who have eaten or handled contaminated fruit to get vaccinated within 14 days.

Allison said that one person in the province has contracted hepatitis as a result, but no other cases have been found. Twelve other cases have been identified in provinces across Canada.

According to Costco, approximately 1,600 households in the province have purchased the product.

While vaccines “aren’t easy to come by,” Costco is offering post-exposure immunization to those who have come into contact with the berries.