Ready-To-Eat Pork Products Are Suspected Source of Listeria Monocytogenes Outbreak

The US Centers for Disease Control and Prevention (CDC) has announced a multistate outbreak of Listeria monocytogenes, this time linked to pork products.

This is the second Listeria outbreak linked to pork products declared this fall, with an outbreak linked to deli ham declared in October.

As of November 21, 2018, there have been 4 cases of infection associated with this outbreak from 4 states. Those who have become ill range in age from 35 to 84 years, with a median age of 60 years. All 4 affected individuals are female and have been hospitalized. No deaths have been reported at this time.

The onset of illnesses ranges from July 1, 2017, to October 24, 2018. Additional illnesses may not be reported yet because of the timeline for reporting Listeria infections which can take between 2 to 10 weeks.

Whole genome sequencing (WGS) conducted on bacteria that were isolated from ill individuals indicated a close genetic relation, suggesting that the individuals are likely to share a common source of infection.

Health officials from the CDC, several states, and the US Department of Agriculture’s Food Safety and Inspection Service (USDA-FSIS) have indicated that early epidemiologic and laboratory evidence has linked this outbreak to pork products from 165368 C. Corporation, which operates Long Phung Foods.

As part of the investigation, interviews were conducted with ill individuals about consumption and exposure in the 4 weeks prior to falling ill. All 4 individuals reported eating “Asian-style foods,” and 3 of the 4 reported shopping at stores where Long Phung Food Products are sold.

Officials from USDA-FSIS also collected samples from items produced at the Long Phung Food Products facility in Houston, Texas. The samples tested positive for the presence of Listeria and WGS indicated that the strain isolated from the products is a close genetic match to the isolates from those who are infected; thus, providing evidence that Long Phung Food products are likely the source of the outbreak.

On November 20, 2018, the company issued a recall for ready-to-eat pork patty rolls produced between May 21, 2018, through November 16, 2018, which were shipped nationwide.

The CDC is advising all consumers to throw away or return recalled products to the place of purchase. Both consumers and retailers should follow the proper sanitation processes to sanitize surfaces where recalled products were prepared, served, or stored.

Clinicians practicing in affected states should be cognizant that patients who present with fever and diarrhea may be suffering from listeriosis. Invasive listeriosis can cause headache, stiff neck, confusion, loss of balance, and convulsions. This condition is concerning for individuals with weakened immune systems and can lead to complications for pregnant women.

This is an ongoing investigation and the CDC will provide updates as they become available.

For the most recent case counts associated with the Listeria monocytogenes outbreak associated with ready-to-eat pork products, check out the Contagion® Outbreak Monitor.