The FDA has released a summary of a new strategy aimed at reducing foodborne outbreaks and illness associated with the consumption of soft fresh queso fresco type cheeses.

Soft queso fresco-type (QFT) cheeses are fresh or un-ripened cheeses that have not been aged. These types of soft cheeses have high moisture, low salt content, low acidity and a shorter shelf life than aged cheeses. They can support the growth of Listeria monocytogenes (L. monocytogenes) and require refrigeration for food safety. Examples of soft fresh QFT cheeses include queso fresco, queso blanco, queso panela, and requeson. Consumers may find these cheeses at retailers, or in prepared dishes at restaurants.

Overview of Listeriosis Outbreaks linked to Queso Fresco-Type Cheese

In 2021, the FDA’s Coordinated Outbreak Response & Evaluation (CORE) Network, in collaboration with the Centers for Disease Control and Prevention (CDC) and state and local partners, investigated a multistate outbreak of L. monocytogenes infections linked to the consumption of queso fresco cheese, a variety of soft fresh QFT, that sickened 13 people. 

During the investigation the outbreak strain was found in a retail sample of queso fresco cheese. The FDA also initiated an onsite inspection of the firm where the cheese was produced. The FDA did not isolate the outbreak strain (or any L. monocytogenes) from the production environment but did identify potential contributing factors, including the failure to identify and implement appropriate controls for L. monocytogenes and lack of environmental monitoring for the presence of pathogens in the facility. (Environmental monitoring is an activity undertaken by a firm to determine if pathogens—including L. monocytogenes—are present in the production environment). The outbreak resulted in 12 hospitalizations, two pregnancy losses and one death in the U.S.

The FDA is aware of other L. monocytogenes outbreaks linked to soft QFT cheeses over the last decade. The FDA’s Coordinated Outbreak Response & Evaluation (CORE) Network investigated five listeriosis outbreaks linked to the consumption of QFT between 2014 and 2017. There were an additional 12 outbreaks of listeriosis in the U.S. during the period 1998‒2014 associated with soft cheeses made from pasteurized milk.¹ Most of these soft cheese outbreaks (8/12) were associated with QFT. Historical outbreaks of listeriosis have been associated with QFT made from unpasteurized milk, but recent outbreaks have been caused by cheeses made from pasteurized milk that was contaminated during the cheese-making process.

The FDA has developed this prevention strategy with the goal of reducing outbreaks and illnesses of listeriosis associated with soft fresh QFT cheeses. L. monocytogenes can cause a severe infection, sometimes leading to death, in susceptible populations.

Summary of FDA’s Strategy to Help Prevent Future Outbreaks of Listeriosis linked to Soft Fresh Queso Fresco-Type Cheeses

Food safety is a shared responsibility. Producers of QFT are responsible for producing safe food, including satisfying applicable food safety requirements. In addition, the FDA believes it is imperative that it shares data, knowledge and information, and works collaboratively to enhance food safety. Based on review of the outbreak findings, historical data and engagements with industry and other stakeholders, the agency has identified measures that can be taken to reduce future incidences of foodborne illness related to queso fresco-type soft cheeses, including:

• Prioritizing inspections with environmental sampling at soft fresh QFT manufacturing firms.
• Engaging with state partners to increase sampling of QFT cheese at retail operations in the U.S. for the presence of L. monocytogenes. This could result in potentially contaminated products being recalled and removed from the market.
• Develop and distribute a publication that outlines the potential causes of recent listeriosis outbreaks in soft cheeses and a fact sheet that describes requirements for Listeria control in cheese manufacturing.
• Collaborate with states and other food safety partners to disseminate training and education materials to producers and consumers of soft fresh QFT.

By implementing these activities, the FDA hopes to:

• Ensure that the cheese industry is aware of regulatory requirements applicable to the production of QFT.
• Enhance compliance with the applicable regulatory requirements by producers of QFT. 
• Verify through inspections and sampling that producers of QFT are adhering to those requirements.

Sources:

[1] Jackson KA, Gould LH, Hunter JC, Kucerova Z, Jackson B. Listeriosis Outbreaks Associated with Soft Cheeses, United States, 1998-2014(1). Emerg Infect Dis. 2018;24(6):1116-8.