Resources for the Control of Listeria monocytogenes for Manufacturers of Soft Fresh Queso Fresco-type Cheeses
This fact sheet is intended to help Queso Fresco-type soft cheese manufacturing groups further their understanding of possible food safety risks that can occur in production and the resources available to help them consistently produce safe food.
What are soft Queso Fresco-type cheeses?
Soft Queso Fresco-type (QFT) cheeses are fresh, unripe cheeses that do not go through a significant aging process. These types of cheeses are white/off-white in color and very moist. They also have a low salt and acid content, which gives them a shorter shelf life compared to that of other aged cheeses. This also means soft QFT cheeses must always be refrigerated. Depending on the country of origin, some of the more popular fresh, soft QFT cheeses are labeled as either Latin-style or Mexican-style cheeses. Well-known examples of QFT cheeses include Oaxaca, Asadero, Queso Blanco, Queso Fresco, Requeson, and Panela, amongst others [1],[2].
What are some concerns with soft Queso Fresco-type cheeses?
The pathogen of primary concern among soft QFT cheeses is Listeria monocytogenes (L. monocytogenes), a type of disease-causing bacteria that specifically causes the infection listeriosis. Outbreaks of listeriosis have been linked with soft QFT cheeses made from raw milk or those that contain ingredients that were contaminated somewhere during the cheese-making process. 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 soft QFT cheeses linked to past outbreaks were often manufactured by smaller-scale producers. These outbreaks have often affected a higher proportion of pregnant Hispanic women and their newborns. Listeriosis infections in pregnant women can result in serious illness, miscarriage, or even stillbirth. Older adults, newborns, and people with weakened immune systems are also at higher risk for developing serious symptoms associated with listeriosis. In addition to the risk of listeriosis linked to soft QFT cheese, the Centers for Disease Control and Prevention has reported multiple outbreaks linked to other pathogenic bacteria in these products, including Salmonella, Campylobacter jejuni, and Brucella [3],[4].
What are some food safety issues identified from past outbreak investigations?
FDA inspections of cheese manufacturers connected with outbreaks of L. monocytogenes illness have found food safety issues including, but not limited to, the following:
- Unlawful use of raw milk in QFT cheese making
- Poor employee hygiene practices
- Inadequate pest control
- Presence or continued existence of L. monocytogenes in production areas
- Irregular and/or unsatisfactory cleaning, washing, and maintenance of equipment
- Inadequate maintenance of facilities, causing issues such as roof leaks, cracked floors, and deteriorated walls
- Inadequate, or lack of, control measures in manufacturing, packaging, and storing products, especially measures needed to lessen the potential for bacteria growth and contamination
- Poor sanitation practices leading to standing water and cross-contaminated (when bacteria spreads from one substance/surface to another) food-contact surfaces
What are some requirements relevant to manufacturers of soft Queso Fresco-type cheeses?
"In general, manufacturers of soft QFT cheeses intended for consumption in the U.S. are required to comply with the Current Good Manufacturing Practice, Hazard Analysis, and Risk-Based Preventive Controls for Human Food Rule (CGMP & PC Rule) as mandated by the FDA Food Safety Modernization Act (FSMA),[5] unless an exemption applies.[6]" This rule identifies steps that all manufacturers must follow to lessen/stop food safety hazards from occurring. Compliance with these requirements results in a lower risk of L. monocytogenes occurring in food and thus reduces total consumer illnesses.
Preventive Controls Requirements: In order to comply with the preventive controls requirements of the CGMP & PC Rule, and thus reduce or stop contamination of their products, facilities must conduct a hazard analysis and create and carry out a written food safety plan throughout production. This plan is to lay out the required preventive controls needed to manage known sources of risk. Examples of preventive controls that could be applied to control L. monocytogenes in soft QFT cheese production include cheese-preparation process controls, workspace and employee sanitation controls, and supply-chain controls on incoming ingredients.
| Preventive Control | Examples for soft QFT cheese manufacturers |
|---|---|
| Process Controls | Milk must be heated (pasteurized) to eliminate germs such as L. monocytogenes and other types of bacteria found in raw milk (see 21 CFR 117.135(c)(1) and 21 CFR 1240.61) |
| Sanitation Controls | Regular cleaning and sanitizing must occur to minimize or prevent bacteria such as L. monocytogenes from becoming established in processing equipment and the production environment (see 21 CFR 117.135(c)(3)) |
| Supply-chain Controls | When the facility relies on the supplier(s) to control a hazard, then the receiving facility is to always use approved suppliers and regularly verify that the supplier(s) has applied adequate controls (see 21 CFR 117.135(c)(4) and 21 CFR part 117 subpart G) |
Current Good Manufacturing Practice (CGMP) requirements
CGMPs address areas including:
- Employee Hygiene
- Equipment and Facility Maintenance
- Training
- Adequacy of Water Supply
- Facility Design (and how it impacts sanitation)
What environmental and product testing for milk and dairy products, like Queso Fresco-type cheese, is required by the CGMP & PC Rule?
The rule includes requirements for environmental monitoring and finished product testing as verification that preventive controls are effective, as appropriate, to the food, the facility, and the preventive controls used throughout (see 21 CFR 117.165), especially for certain ready-to-eat products (see 21 CFR 117.130(c)(1)(ii)). For example, environmental monitoring for L. monocytogenes may be required for manufacturers of soft QFT cheeses that are exposed to possible hazards in the environment prior to packaging, especially when the packaged cheese can support bacterial survival and/or growth, and does not receive a treatment that would significantly minimize the presence of L. monocytogenes.
What resources are available for manufacturers of soft QFT cheese?
Manufacturers of soft QFT cheese have many resources available to them, including:
FDA resources:
- FDA-developed Guidance Documents
- Small Entity Compliance Guide: What You Need to Know About the FDA Regulation: Current Good Manufacturing Practice, Hazard Analysis, and Risk-Based Preventive Controls for Human Food (21 CFR Part 117): Guidance for Industry
- Draft Guidance for Industry: Control of Listeria monocytogenes in Ready-To-Eat Foods
- The Technical Assistance Network (TAN)
- The Food Safety Preventive Controls Alliance (FSPCA)
- FSPCA Participant Training Courses
- Food Safety Plan Builder
Non-FDA resources:
- University food safety specialists, especially those aimed in assisting farmers/producers
- Regulation partners and food safety experts at state and local government agencies
- Cheese manufacturers and trade associations
What other information is available for manufacturers of soft QFTC?
[1] Guide to California Hispanic-style Cheeses
[2] Hispanic-style cheeses and their association with Listeria monocytogenes
[3] CFR - Code of Federal Regulations Title 21
[4] Check the Cheese Avoid Listeria
[5] FSMA Final Rule for Preventive Controls for Human Food
[6] Guidance for Industry: Determination of Status as a Qualified Facility