Tag Archives: testing and detection

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Cronobacter Regulation and Detection


As we saw with the recent large scale recalls of infant formula, Cronobacter has become a pathogen of growing public health concern for vulnerable populations. Our guest experts, Sally Powell Price, Regulatory Expert Food and Beverage Safety at MilliporeSigma, and Andrew Lienau, Food Regulatory and Validation Senior Expert at MilliporeSigma, detail the importance of Cronobacter in food manufacturing, summarize detection solutions and provide a glimpse into the future of this potentially deadly pathogen.

Why is Cronobacter detection important?

Cronobacter are ubiquitous pathogens that have been isolated from a wide variety of sources including dried herbs and spices, soil, starches and milk products. They are found naturally in the environment, for example, in our yards, kitchens and living rooms. They even can live on surfaces including kitchen counters, sinks and food facility manufacturing equipment.

Andrew Lienau
Andrew Lienau

Infant formula, as we have seen in recent years, can be contaminated by this type of bacteria. While Cronobacter infections are rare, they can be fatal to newborns and immunocompromised individuals. When these infections are diagnosed in infants, they are often linked to consumption of powdered formula.

According to CDC, the potential mortality rate for Cronobacter infection is 40%. It has high risks for newborns, especially low-birth weight infants. Cronobacter is highly resistant to stress and can survive in products such as powdered infant formula for more than two years, which is the major risk factor. Almost all Cronobacter species are linked to human infections (adults and infants).

How is MilliporeSigma’s Assurance® GDS method fit-for-purpose for detection of Cronobacter?

Ensuring an assay is robust is a lengthy process. Microbiology methods are reviewed and approved by standards or certification bodies. Certification organizations for food microbiology include AOAC International and Health Canada in North America and AFNOR Groupe and MicroVal in Europe. Approved testing methods undergo rigorous, systematic scientific scrutiny and validation to ensure they are credible and legally defensible and thus can be used with confidence by industry, regulatory agencies, research organizations, testing laboratories and academic institutions. It is important during this validation process to demonstrate that the methods are reproducible and provide consistent results across a variety of sites and users.

MilliporeSigma logo

During the certification process, methods are compared against standard reference methods or a “gold standard.” For example, there is a reference method developed by ISO for enrichment of Cronobacter from foods. Through the certification process, the MilliporeSigma Assurance® GDS method performed as well as the reference method. But the GDS Cronobacter method requires less time, materials and personnel to obtain comparable results. This certification improves both industry confidence and access to a rapid, reliable method for detection of Cronobacter in food.

The GDS for Cronobacter method has been reviewed and approved by both MicroVal (MicroVal 2017LR77) and AOAC International (AOAC PTM 121903; AOAC OMA 2021.08). These review processes can take more than one year from initial submission of protocol to generation of the validation data, including final review of the results by the certification organization. Outside expert peers also review the method for approval.

This year MilliporeSigma was honored that the Assurance® GDS Cronobacter method was recognized as the Method of the Year Award in Microbiology by AOAC International.

What are the regulatory implications and outlook for Cronobacter & infant formula?

The recent move towards restructuring the FDA and Human Foods Program was in part driven by the high-profile recalls and subsequent infant formula shortages due to Cronobacter contamination. Over the next year, we can expect to see continued regulatory scrutiny of Cronobacter and similar pathogens or analytes that put infants and other vulnerable populations at risk.

Sally Powell Price
Sally Powell Price

Last year, the U.S. FDA released a strategy to help prevent Cronobacter illnesses, and in 2023, they expanded their approach by increasing inspection capacity and updating the Infant Formula Compliance program.

Beginning in 2024, Cronobacter infection will be a nationally notifiable disease as recognized by the US Centers for Disease Control (CDC). The FDA will collaborate with states and public health labs to bolster testing efforts. This will provide more clinical isolates, complementing the FDA’s environmental and product sample collection and sequencing strategies. It will also increase sequencing data available in the NCBI database in hopes of bridging scientific gaps related to Cronobacter.

Furthermore, the FDA is reviewing existing testing criteria to potentially enhance finished product safety with a focus on infant formula regulations led by the Office of Critical Foods. The Agency is collaborating with Congress to explore legal avenues to require firms to report Cronobacter-positive product test results, among other requirements.

For infant formula manufacturers it’s not all about regulation, however. Manufacturers and stakeholders now have expanded opportunities for collaboration with the FDA and related working groups like the National Advisory Committee on Microbiological Criteria for Foods (NACMCF). These partnerships offer a unique chance for productive dialogue and the potential to engage in valuable initiatives aimed at providing scientific insights into Cronobacter and its prevention, including elective surveillance programs. Additionally, stakeholders in the infant formula industry can strengthen efforts to be transparent with consumers. They may actively participate in public meetings and engage with industry associations such as the Association of Food and Drug Officials (AFDO) or The Partnership for Food Safety Education (PFSE), fostering open discussions and sharing best practices to enhance safety and quality standards in the production and preparation of powdered infant formula. This proactive engagement not only fosters consumer confidence but also contributes to a safer environment for infants and vulnerable populations.















Margaret Vieth

Optimizing Environmental Monitoring Programs

By Margaret Vieth
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Margaret Vieth

The food manufacturing industry has seen a shift toward increased environmental monitoring testing to help mitigate risks in food processing. But it can be difficult for producers to build out environmental monitoring programs due to the lack of detailed regulatory guidance, particularly when looking at how many samples to collect and from which locations or surfaces they should be collected.

Below are five tips to help food manufacturers build more efficient and effective environmental monitoring programs.

1. There Is No “One Size Fits All” Approach to Environmental Monitoring

A successful environmental monitoring program is one that’s customized for each facility. When creating a program or evaluating an existing program, it is important to organize a cross-functional team that includes those who are most familiar with your products and processes. This cross-functional team can help determine critical program details such as determining from which areas samples will be collected and the frequency of sample collection.

One approach is to establish a comprehensive list of every site that will be tested over time, then evaluate how often those areas should be swabbed using a risk-based approach. A risk-based approach involves determining which sites within a manufacturing plant are the highest risk and which are the lowest risk, and then testing the highest risk sites more often and the lower risk sites less often.

Risk level is based on: the proximity of the test point to the food contact surface; how difficult the area or surface is to clean or sanitize; and/or historical data and knowledge of the facility and products. The goal is to collect data from all relevant areas in the plant over time, while spending the most time on those that are highest risk.

2. You Can’t Detect What You Don’t Collect

While it seems counterintuitive, food manufacturers should be seeking positive results when conducting environmental monitoring testing. It’s important to remember that all environments can and most likely will become contaminated with a pathogen at some point in time. If an environmental monitoring program does not detect a positive result for a common environmental contaminate throughout the course of a year, it may indicate that the right areas are not being swabbed or that they are not being swabbed well enough.

When environmental monitoring programs uncover contaminated areas through positive results, it offers the opportunity for producers to implement corrective and preventative actions to improve their programs long term. A food processor’s food safety program can be seen as stronger and more reliable when the goal is to find and address the positive.

3. Use the Right Tools

A major factor in the success of environmental monitoring testing lies in the types of tools being used to collect the samples and the techniques used to collect them. When investigating tools for an environmental monitoring program, there are two key traits to keep in mind. First, it is important to ensure a collection device uses a neutralizing buffer that is effective against the sanitizers in the environment. The collection buffer should keep organisms alive long enough to run an accurate test, while also having a wide enough capacity to neutralize the sanitizer on the surface being sampled. This is an especially important consideration in processing environments that are continuously experiencing sanitizer changeovers.

Second, collection tools need to effectively access and collect organisms from the surface of the sample area. Biofilms—protective barriers of bacteria where pathogens or other organisms can thrive—are a big challenge when collecting samples. If the collection devices are not well suited to collecting or penetrating biofilms, there is a risk that the biofilm as well as all the living organisms and potential pathogens within the biofilm are not collected. Using devices that have scrub dot technology allows producers to collect the biofilm itself, creating a better sample for an even stronger environmental monitoring program.

4. Don’t Forget to Re-evaluate

To ensure you are getting the most out of your environmental monitoring program, conduct regular re-evaluations of the program. Periodic reviews are important as environmental factors are always changing. In a single year, food manufacturers may introduce new employees, new equipment, new processes, new products and new vendors. All these factors can have an impact on the quality and hygiene of the environment and the products you produce. Therefore, environmental monitoring programs should be viewed as a continuous improvement program rather than something that’s set up once and left alone.

5. Take Advantage of Education and Training Resources

Providing proper training and education for the entire environmental monitoring program team can make a significant difference in the effectiveness of the program. There are numerous educational resources available for environmental monitoring program teams. These should be utilized as you build and assess your protocols and provided to new team members. Involve the sample collection team in the process of creating the program and ensure the program protocols are readily available and understood by all team members.

Creating robust programs to help mitigate food safety risks, such as those found within a manufacturing facility’s environment, is critical to protecting consumers and your company. Despite a lack of detailed regulations around environmental monitoring program development, food manufacturers can create successful programs by customizing their protocols to their facilities, conducting routine evaluations, searching for positives, utilizing proper collection tools and providing proper training and education. Sources of potential contamination are numerous, but a strong environmental monitoring program can help find them.


Thermo Scientific SureTect Listeria PCR Assays Granted AOAC Official Methods First Action


A poster by Thermo Scientific presented ay the 2022 IAFP Conference in August showed validation methods of the company’s SureTect Listeria monocytogenes and Listeria species PCR Assays, which led to AOAC recognition for official method of first action.

For the unpaired collaborative study, Evangelos J Vandoros, et al, compared the SureTect Listeria PCR Assays Method to the method outlined in the FDA-Bam Chapter 10. The matrix used for the study was full-fat cottage cheese with a test portion of 25g.

The researchers validated both SureTect Listeria PCR Assays (Listeria species and Listeria monocytogenes) in this study, as they follow the same method protocol and are validated for the same matrices.

Outcomes showed consolidated dLPOD data from 12 collaborators for the SureTect Listeria PCR methods and the FDA-BAM Chapter 10 reference method. The data was within confidence intervals showing that there was no significant difference between the SureTect methods and the reference method. The time to result was less than 24 hours.

Based on these findings, the SureTect Listeria monocytogenes and Listeria species PCR Assays were both granted AOAC Official Methods First Action

The validated categories for the assays include milk and dairy, fresh produce, seafood, raw meat, ready to eat/reheat and environmental,