Shopper Loyalty Card Data — Outbreak Response Success Stories

During a 2021 multistate outbreak of Salmonella I 4,[5],12:i:- illnesses associated with Italian-style meats, ill people shared the last four digits of their credit card number with public health officials who worked closely with a retailer to obtain food purchase information. This information confirmed the specific Italian-style meat product that ill people purchased. The information was also used to guide sampling and traceback activities, which led to a recall of the Italian-style meat products.

During a 2021 multistate outbreak of Salmonella Infantis and Typhimurium illnesses associated with Italian-style meats, ill people reported purchasing Italian-style meats from a retailer with a shopper card program. Ill people shared their shopper card numbers with public health officials who worked with the retailer to obtain the shopper histories. The shopper history information was used to confirm the food vehicle and trace the products back to the producing establishment.

During a 2020 multistate outbreak of 80 Salmonella illnesses from 15 states associated with produce, a retailer used its shopper card program to provide case-patient family shopper histories within 24 hours of the request, allowing our agency to identify the produce items, purchase dates, and store locations most likely linked to illness. The retailer then provided product distribution pivot tables linking stores where these products were sold with shipments and growers, allowing us to determine the most likely sources. The retailer’s novel use of these records enabled investigators to take action at the farms days earlier than ever before.

We were investigating a cluster of salmonella cases that reported consuming prepackaged salad mixes (slightly different descriptions) that were purchased from a common chain store. We received permission from cases to obtain their purchase records from the store and the company quickly produced those purchase records. The records identified a common brand and variety of salad mix, which allowed the store to immediately pull the product from store shelves and contact everyone who had purchased the product. This quick response undoubtedly helped prevent further illness.

In a 2018 multi-state outbreak of E. coli O26 illnesses associated with ground beef, three different mechanisms allowed investigators to obtain purchase data that led to identification of the ground beef source and a “supplier-level” recall. Retailer 1: this retailer established a phone line for cases to call with their credit card information which allowed the retailer to look up their purchases. Retailer 2: This retailer looked up a case’s purchases made by check using the case’s check cashing card number, which was required by the retailer for check purchased from this retailer. Retailer 3: one case provided a receipt for ground beef purchased from this retailer.

In a 2013 outbreak which sickened 165 people from 10 states with Hepatitis A, after consumption of pomegranate arils, regulatory officials were able to utilize retailer-provided membership program records to identify the implicated product, resulting in a recall. The retailer used purchase records to identify and notify 250,000 customers via automated phone calls that they had purchased the implicated product.

During the Salmonella Carrau outbreak, we requested 12 shopper card records from the supermarket, which were all provided within 24 hours of request.

During the Salmonella Newport ground beef outbreak our agency was able to request records early on in the investigation to confirm ground beef purchase history and exposure information.

During the 2013 2014 Salmonella Heidelberg outbreak associated with chicken, CDPH obtained shopper purchase records for 92 cases from two grocery store chains. These records were shared with USDA-FSIS and enabled the agencies to conduct trace back on specific chicken products listed on the purchase histories and identify the source of the outbreak.

In a 2011 outbreak which sickened 43 people from five states with Salmonella Enteritidis, retailer shopper card records showed that cases had common purchases of pine nuts from bulk bins. This finding ultimately led to a recall of adulterated pine nuts.

In a 2014-2015 multi state outbreak of Listeria monocytogenes illnesses associated with commercially produced prepackaged caramel apples, one case provided an original purchase receipt that verified purchase of caramel apples prior to illness onset. This receipt helped focus that investigation and eventually led to a recall.

Use of the store’s government shopper card purchase data request form has helped to streamline the process for obtaining shop or purchase information, eliminating the need for notarization of request by case patients.

Shopper card information helped identify a suspect food vehicle in a case where the ill patients could not recall their food history.

In a 2010 outbreak which sickened 272 people in 44 states with Salmonella Montevideo, retailer membership program records allowed investigators to identify salami product purchases in common amongst the cases. This finding led to a recall and further investigation at the manufacturer, where pepper was identified as the contaminated ingredient.

In a 2019 multi-state outbreak of Salmonella Dublin illnesses from eight states that was linked to ground beef, one case’s Electronic Benefits Transfer (EBT) card was used to look up and identify purchase information, which provided supporting evidence for a recall.

We have used loyalty data to track food product purchases by reported cases in several outbreaks. We have found the information extremely valuable in identifying potential foods that were implicated in the outbreak. We have also found that the use of loyalty or shopper card data for this purpose is well-supported by consumers.

We were investigating a cluster of salmonella cases that reported consuming prepackaged salad mixes (slightly different descriptions) that were purchased from a common chain store. We received permission from cases to obtain their purchase records from the store and the company quickly produced those purchase records. The records identified a common brand and variety of salad mix, which allowed the store to immediately pull the product from store shelves and contact everyone who had purchased the product. This quick response undoubtedly helped prevent further illness.