Salmonella From Charcuterie Meats, 2023–2024: How Shopping Records Sped a Recall

Since 2010 three multistate outbreaks of salmonellosis in the United States have been linked to charcuterie-style meats. From December 2023 to March 2024, CDC, the U.S. Department of Agriculture's Food Safety and Inspection Service (USDA-FSIS) and health departments in 33 states investigated another — the largest U.S. outbreak of infection linked to such meats since 2010. Customers' grocery purchase records were central to finding its source quickly.

Detecting the outbreak

On December 19, 2023, PulseNet, CDC's national molecular subtyping network for foodborne disease surveillance, flagged a cluster of 13 Salmonella enterica I 4:I:- infections in five states. Whole genome sequencing showed the strains were closely related, suggesting an outbreak. Patients' accounts of what they had eaten pointed to charcuterie, and the bacteria were genetically related to those from a 2021 outbreak linked to salami sticks.

A case was counted in the outbreak if the infection's strain was within three allele differences of the outbreak strain and the illness began between November 20, 2023 and February 10, 2024.

Who got sick

PulseNet found 104 cases in 33 states. Patients ranged from 1 to 92 years old, with a median age of 48, and 40% were female. Twenty-seven were hospitalized. No one died.

People infected with the outbreak strain, by the date their illness began, United States, 2023–2024. Where the onset date was missing, the date the specimen was collected minus three days was used. CDC, MMWR.

Following the meat

In their first interviews, two patients said they had eaten the same charcuterie product from "company A" in the week before falling ill. It held three ready-to-eat pork products that are fermented, salt-cured and dried rather than cooked: coppa, salami and prosciutto. The two had bought it at different stores of the same national grocery chain.

Three days after the outbreak was identified, CDC sent states a questionnaire about charcuterie and asked the grocery chain for purchase records — receipts and shopper-card histories — for patients who shopped there and agreed to share them.

• Eating history. Of 68 patients in 27 states with food histories, 50 (74%) had eaten charcuterie-style meat before falling ill. That was significantly higher than the 39% reported in the 2018–2019 FoodNet Population Survey, the benchmark for spotting when a food is eaten unusually often in an outbreak.
• Lab confirmation. The Minnesota Department of Agriculture found the outbreak strain in a company A charcuterie product from a patient's home, and that lot was recalled. Washington and Vermont tested company A products and found no Salmonella.
• Traceback. Sixteen purchase records from 10 states went to USDA-FSIS. Eleven charcuterie purchases, covering several product lots, led back to two of company A's federally regulated plants. The remaining purchases led to other suppliers.

Inside the plants

USDA-FSIS carried out for-cause food safety assessments — full reviews of a plant's food safety system prompted by a specific concern such as an outbreak — at both company A plants and collected 179 samples of product, food-contact surfaces and the environment. Two samples of a ready-to-eat product containing coppa grew Salmonella, though not the outbreak strain. The assessments found that the coppa might not have been salt-cured and dried enough, which could leave Salmonella in the finished product.

USDA-FSIS allows no Salmonella at all in ready-to-eat products. The positive samples, the epidemiology and the risk of underprocessing together led, on February 12, to a wider recall of every company A product containing coppa that was still within its shelf life.

Lessons

Charcuterie-style meats are usually made by fermenting and drying or salt-curing and drying, not by cooking. Done properly, that process controls the bacteria that make people sick; done carelessly, the meat can be underprocessed. USDA-FSIS requires plants to show scientific evidence that their process achieves a 5-log reduction of Salmonella (or of another pathogen) and makes the product shelf-stable, among other controls, and publishes guidance on producing these meats safely.

Purchase records helped investigators form their first theory and laid the groundwork for the traceback. Together with patient interviews, they allowed the contaminated products to be identified and recalled 17 days after the investigation began — about a week faster than earlier CDC-led foodborne investigations that did not use purchase records — probably preventing more illnesses.

Sources

• Lodato A, Cote A, Rounds J, et al. "Notes from the Field: Multistate Outbreak of Salmonella enterica I 4:I:- Infections Linked to Charcuterie-Style Meats — United States, 2023–2024." MMWR 74(17). CDC.