Leveraging Food Purchase History to Solve Foodborne Outbreaks

The Shopper History Outbreak Partnership (SHOP) is a group of public health and food safety officials dedicated to working closely with industry partners to use consumer food purchase data as a tool to solve foodborne outbreaks, remove contaminated food from the marketplace, and prevent additional illnesses.

How Food Purchase History Protects Public Health


Best Practices for Investigators on Collection & Use of Shopper History during Foodborne Outbreak Investigations

Shopper history: best practices for use during foodborne illness investigations

Shopper history (any record that provides information about a specific shopper’s food purchases) provides an objective source of information to investigations and is an essential tool in solving outbreaks. This best practice document provides recommendations that local, state, and federal public health and regulatory officials can use when requesting and using shopper history as part of a foodborne outbreak investigation. Learning about shopper history best practices may help industry partners and consumers develop ideas for how to better collaborate with government investigators to solve outbreaks.


Success Stories

Limited Credit Card Information Helps Solve Outbreak

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.

Shopper Card Information Quickly Confirms Food Vehicle

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.

Novel use of data leads to quick response

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.

Retailers shopper card program yields purchase histories within 24 hours

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

Industry records confirm ground beef purchase information

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.

Loyalty cards trace purchase history for 92 illnesses

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.

Shopper cards identify suspect food vehicle

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.

Receipt verifies consumer purchases in Listeria outbreak

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.

Credit card and shopper cards help identify suspect food vehicle

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.

Credit card, check cashing card, and receipt helped identify source of ground beef

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.

Membership program used to trace purchase data and notify customers of recall

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.

Retailer streamlines government requests using standardized form

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.

Using shopper data can help to narrow down suspect foods

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

Membership program identifies common food product among ill people

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.

Novel use of EBT card leads to recall

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.

Loyalty purchase data for outbreak investigations has customer support

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.

Membership numbers assist in rapid removal of product

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.

If you would like to share your success story on the site, please email the completed form to the Shopper History Outbreak Partnership (SHOP).


Frequently Asked Industry Questions

Regarding Consumer Purchase Data Sharing   

Rapid and effective information sharing between the food industry and government officials can be a critical component to solving foodborne outbreaks.  Successfully solving a foodborne outbreak requires cooperation and collaboration while also acknowledging each other’s limitations and concerns on information sharing.   Below are some commonly asked questions and answers regarding sharing of consumer food purchase data.  Processes and requests may vary based on different states’ regulations. It is best to work with your company’s legal counsel and the state’s regulatory authorities prior to food emergencies to determine information sharing requirements and processes.  

Q1: How do I know that the consumer has consented to sharing their food purchase information with public health officials? 

Most investigators will not request purchase history from industry without having already obtained permission from the consumer during the epidemiologic interview. Consumers may consent verbally over the phone during an epidemiologic interview, or in writing via paper form, email, or text. This information will be shared with the retailer upon requesting the food purchase history. It is recommended that the company’s legal department and the state agency discuss the data sharing request process before an actual event, to clarify expectations and prevent delays.  

Q2: How do health officials protect privacy and maintain confidentiality?  

Health officials only share information with other public health and regulatory officials and industry if it is needed for the investigation. Once the shopper history is received, the requesting agency will redact the personal information (name, phone number, shopper card number, credit card number, etc.) before sharing with any other public health or regulatory partners investigating the outbreak. 

Q3: During a foodborne outbreak investigation do I need to provide information about everything a person purchased?  

Shopper history inquiries are focused on food/grocery items; data like pharmacy records are typically not needed (or wanted) by the investigating agency. Other non-food purchases like liquor, gasoline, and tobacco are not needed during a food traceback investigation. Companies with questions on what to include in a purchase history request should contact the requesting agency.  

Q4: How do health officials determine the timeframe of interest when requesting shopper history? 

The timeframe of interest can vary greatly depending on the food product of interest (particularly its shelf life) and the reason for the investigation. An investigation may be initiated because of a pathogen (i.e., E. coli, Salmonella, Listeria) or other contamination (chemical or physical contaminant). The time it takes for someone to become ill after eating the product (the incubation period) will also have an effect on the date range for the shopper history request. 

Q5:  Is my company required to provide consumer purchase data if we do not have a loyalty/shopper card program? 

If your company can track the consumer’s purchase data through other transaction or payment records (i.e., phone number, credit/debit cards, etc.), you might be required to turn those records over if the state has legal authority to obtain them. This varies from state to state.  

Q6:  If a state has laws in place that allow them to obtain consumer purchase data, should our company still wait until we obtain permission directly from the consumer before releasing the information to government officials?

Industry’s decision on requiring customer permission is internal, but bear in mind that generally most investigators will not request purchase history from industry without having already obtained permission from the consumer during an interview.  To prevent delays during an emergency, it is recommended that the company’s legal department and the state agency discuss the data sharing request process prior to an actual event, so expectations are clear. Industry may consider whether consumers can ‘opt-in’ during signup for loyalty/shopper cards to grant advance permission to share their data in case of an emergency. 

Q7: Can we be sued/held liable for releasing consumer purchase records if the State is authorized to obtain those records? 

The state statutes providing public health agencies with the authority to access records may help to reduce the risk to the retailer when they are providing records. Generally, the consumer has already granted permission to investigators during the interview. Laws within each state may vary, so it is recommended that the firm consult its legal counsel on this topic prior to an actual event.  Some state citations allowing them to obtain records may be found here https://www.afdo.org/resources/purchase-history/  

Q8:  Consumers buy products from us using various online grocery delivery services.  Are we still responsible for providing purchase data or does it become the responsibility of the delivery service to do so?

If your company has a record of the purchase, even if it is delivered by a third party, you would be expected to provide the information.  

Q9: Why would a government agency ask for a shopper history before a suspected food item has been identified?  

Food purchase history may be requested to test a hypothesis of which food item(s) may be a likely vehicle but have not yet been confirmed. Purchase histories may be compared to identify common food items between ill people who are part of an outbreak. More information about the investigation process can be found at How Food Purchase History Protects Public Health


State Legal Authorities

During multi-jurisdictional foodborne illness outbreak investigations, government officials may have an urgent need to obtain consumer’s product purchase information from industry in order to determine common food links between ill people. Industry partners must determine how to balance these requests with any potential legal concerns related to protecting consumer privacy, which may cause a delay in providing information to investigators. As a result, some industry partners have begun asking regulators to provide references to their legal authority to obtain these records.

This website is an online resource for industry to more rapidly access available states’ legal authorities or other documentation allowing government officials to obtain information such as consumer product purchase records from the food industry for investigative purposes.

The italic states have statutory citations that can be used for obtaining consumer purchase records during investigations.

Alabama

Alaska

Arizona

Arkansas

California

Colorado

Connecticut

Delaware

Florida

Georgia

Hawaii

Idaho

Illinois

Indiana

Iowa

Kansas

Kentucky

Louisiana

Maine

Maryland

Massachusetts

Michigan

Minnesota

Mississippi

Missouri

Montana

Nebraska

Nevada

New Hampshire

New Jersey

New Mexico

New York

North Carolina

North Dakota

Ohio

Oklahoma

Oregon

Pennsylvania

Rhode Island

South Carolina

South Dakota

Tennessee

Texas

Utah

Vermont

Virginia

Washington

West Virginia

Wisconsin

Wyoming

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