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FDA Releases Findings on RTE Dips and Spreads

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In 2021, the U.S. Food and Drug Administration (FDA) conducted a routine assignment to collect domestic multi-commodity ready-to-eat (RTE) refrigerated dips and spreads to test for Listeria monocytogenes and Salmonella spp. The agency’s goal in conducting this assignment was to determine the prevalence of these pathogens in RTE dips and spreads and remove adulterated products from the market, when possible.

The assignment, which ran from March 2021 to January 2022, found that four out of the 747 samples tested were contaminated with Salmonella or L. monocytogenes. Ready-to-eat foods can become contaminated with environmental pathogens from harborage sites in the food manufacturing environment or process. Cross-contamination from ingredients can also occur.   Additionally, dips and spreads often have a pH and water activity that favor bacterial survival and outgrowth.  Consumers typically eat these dips and spreads without a ‘kill step,’ such as cooking, to reduce or eliminate any pathogenic bacteria that may be present. As such, dips and spreads contaminated with L. monocytogenes or Salmonella can present a significant public health risk. Ready-to-eat dips such as hummus and cheese spreads have been associated with multiple recalls over the past few years. The FDA’s assignment was initiated due to five recalls of hummus products and six recalls of multi-commodity dips found to be contaminated with L. monocytogenes or Salmonella from FY2017 through FY2020.

During the sampling assignment, the FDA identified Salmonella Havana in a sample of hummus from a retail establishment in California.  The FDA notified the manufacturer of the hummus and a recall was initiated.  The FDA conducted a follow-up inspection at the manufacturer of the contaminated product to evaluate the firm’s manufacturing operations and collect environmental samples. The FDA found that the firm did not establish and implement adequate written procedures for monitoring sanitation control procedures (i.e., cleanliness of food-contact surfaces). The environmental samples collected at the follow-up inspection did not yield any positive pathogens, however, the agency still issued a warning letter after the follow-up inspection.  After taking corrective actions, the firm was unable to identify a root cause for the Salmonella Havana contamination in the hummus.

The FDA identified L. monocytogenes in three samples from a retail establishment in Colorado and the agency notified the firm where the positive samples were manufactured. All three of the samples contaminated with L. monocytogenes were produced by the same manufacturer. Upon notification of the contaminated samples, the firm recalled and destroyed the products associated with the positive findings. The agency issued a Consumer Advisory in conjunction with the firm’s recall.

The agency conducted a follow-up inspection at the manufacturer of the three contaminated products. The follow-up inspection sought to evaluate the firm’s manufacturing operations and collect environmental samples to determine potential sources and routes of contamination. The FDA found L. monocytogenes in 23 swabs collected within the production environment, including samples collected from food contact surfaces. WGS analysis was conducted on the L. monocytogenes isolates obtained from both the retail product samples and the inspection environmental samples. The isolates were a genomic match to each other.

The FDA’s follow-up inspection determined the firm’s employees were not trained in food safety or hygiene practices and found multiple instances of deficient sanitation practices related to equipment, utensils, and employees. The agency determined that the firm did not respond appropriately to the positive samples identified in the sampling assignment and had not addressed objectionable conditions observed by the FDA during a previous 2020 inspection.  The firm went out of business at the end of June 2021.

Underscored in the FDA’s report is the necessity for manufacturing firms to have good manufacturing practices in place, as well as a proper environmental monitoring program and adequate training for its staff as part of their standard business operating procedures.

Deibel Laboratories has years of experience in conducting shelf-life studies, formulation reviews, and validations for refrigerated dips and spreads.  Our staff of industry experts is ready to assist you in assuring that your manufacturing processes and facilities comply with the stringent food safety standards required by the FDA and USDA.  With a complete suite of accredited pathogen testing methods and the testing capacity of 15 laboratories strategically placed throughout North America, Deibel Laboratories is your one-stop for assuring food safety compliance.

Contact us at Sales@DeibelLabs.com for more information about a laboratory near you. Visit us at https://deibellabs.com/services/deibel-guardianemp/ to learn more about our environmental monitoring program, Deibel GuardianEMPsm. Link to FDA findings: FY21-22 Sample Collection and Analysis of Domestic Refrigerated RTE Dips and Spreads | FDA

The Eight Most Important Recommendations for Controlling Listeria monocytogenes in Retail Delicatessens

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The USDA Food Safety and Inspection Service (FSIS) recently published a guidance document that provides recommendations that retailers can use in delicatessens to control L. monocytogenes contamination of ready-to-eat (RTE) meat and poultry products. This 2023 document is a revised version of the 2015 FSIS Best Practices Guidance for Controlling Listeria monocytogenes (Lm) in Retail Delicatessens. It reflects the FSIS’s current thinking on this topic and is not a regulation. While focused on small firms, the recommendations made will be useful for all meat and poultry retail firms.


Recommendations are based on the joint FSIS, Food and Drug Administration (FDA), and Centers for Disease Control and Prevention (CDC) 2013 Listeria monocytogenes in Retail Delicatessens Interagency Risk Assessment. The assessment summarizes the risks posed by L. monocytogenes from the consumption of RTE foods commonly prepared and sold in retail delis.

The guidance addresses:

  • Actions retailers can take in the delicatessen (deli) area to decrease the potential for
    L. monocytogenes growth and cross-contamination.
  • Steps retailers can take to help ensure that deli products are maintained under sanitary conditions
    that do not allow L. monocytogenes adulteration of the product.
  • Information from the U.S. Food and Drug Administration’s (FDA) Food Code, scientific literature,
    other guidance documents, and lessons learned from meat and poultry establishments that
    retailers can use to control L. monocytogenes.
  • Helpful tools that retail firms can use to identify potential gaps in current best practice procedures.
  • The eight most important recommendations for retail deli operations.

Retailers can use the best practices identified in this guidance to help ensure that RTE meat and poultry products in the deli area are handled under sanitary conditions and are not adulterated, as defined in the Federal Meat Inspection Act (FMIA) and Poultry Products Inspection Act (PPIA).

While these practices are designed to control L. monocytogenes specifically, they also may help control other foodborne pathogens that may be introduced into the retail deli environment and other facilities where consumers take possession of food. No single action or practice will control L. monocytogenes contamination. Therefore, by following the best practices in this guidance and the Food Code, retailers can help ensure that RTE products are not adulterated with L. monocytogenes, and that the potential for listeriosis is decreased.

A Deli Self-Assessment Tool is provided for deli operators in Appendix A of this guidance to help them identify the best practices they are using and to assess whether they need to adopt others.

A Comprehensive Approach: The Eight Most Important Retail Deli Recommendations to Prevent
Conditions That May Cause Adulteration (Source: USDA FSIS

A Decision Guide for Determining Method Equivalence

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Members of the Verification/Validation subgroup of IAFP’s Analytical Methods Professional Development Group (PDG) published a series of articles in Food Protection Trends discussing validation of new food matrices for use with accredited rapid methods. The focus has been on determining a more practical approach for conducting these type of studies. This most recent article “Evaluating Microbiological Method Equivalence – A Decision Guide” appears in the May/June 2023 issue of Food Protection Trends.

The selection of a validated microbiological method, whether a reference method or alternative rapid method, is a critical decision that affects a company’s assessment of the appropriateness of their Food Safety system. There are various factors that a laboratory can consider when determining which equivalent method to use including cost, time to results, or an affinity for a method they have been using for years. Many circumstances can arise that cause a laboratory to change methods. In such an event, how is a laboratory to determine whether two methods are equivalent to one another if neither of them is a reference method? A thought process to guide this decision is outlined in this article, providing a rationale to determine equivalency between a variety of accredited methods validated for the same matrix and sample size. This allows flexibility and choice so that laboratories are able to meet critical needs efficiently when situations arise such as kit shortages, equipment malfunction, and increasing costs.

Past publications in Food Protections Trends by the Validation and Verification Subgroup include:

“Alternative Approaches for Qualitative Microbiological Method Matrix Additions”
“Microbiological Detection Methods — Assuring the Right Fit”
“Selection of Pathogen Strains for Evaluating Rapid Pathogen Test Methods Applied to New Matrices”

The FDA Releases 2022 Cantaloupe Outbreak Investigation Report

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By Ryan Maus

In August 2022, a CDC epidemiological investigation and traceback data identified a multistate cluster of Salmonella Typhimurium illnesses in the upper Midwest indicating melons as a potential source of exposures. The outbreak was traced to cantaloupe and resulted in eighty-seven illnesses and thirty-two hospitalizations across eleven states. The following describes FDA’s investigational findings and provides their recommendations to growers of melons and similar produce.

The FDA utilized traceback data to identify a common packinghouse of suspect cantaloupes associated with the outbreak. However, there was no convergence to a single shipment of products. Three farms in southern Indiana that supplied the common packinghouse were identified as potential sources of cantaloupe. Around the growing locations other commodities were grown such as grain, oilseed, and beans; interspersed with various vegetable crops, including melons; and several poultry feeding operations. Heavy rains had also occurred in the growing region in late July resulting in floods.

Sampling of the packing house, the three farms, and the surrounding lands resulted in numerous findings of Salmonella, but only one of the farms produced an isolate genetically related to the outbreak strain (i.e., having an intermediate level of differences in genomes but not a genetic match). The results suggest that Salmonella presence is a reoccurring issue that may impact the safety of melons grown in this region.

FDA provides the following recommendations/requirements to producers of melons and similar produce.

  • Review current conditions and practices to determine whether they are adequate or if additional
  • prevention measures are warranted.
  • Understand previous land use to identify and address potential sources of pathogens that may
    affect their farming operations.
  • Assess risks that may be posed by adjacent and nearby land uses, especially as it relates to the
    presence of livestock, poultry, and the interface between farmland, and other agricultural areas.
  • Consider additional tools such as pre-harvest and/or post-harvest sampling and testing of
    products to help inform the need for specific prevention measures.
  • Poultry manure, while valued for its fertilizer value, is a known reservoir for Salmonella
    spp. Proper application of a manure that has been treated with a validated and verified process
    to reduce pathogens (e.g., composting with time and temperature measurements) can
    significantly reduce the potential for the integration of Salmonella or other human pathogens into
    soils (as compared to the use of raw manures).
  • Inspect, maintain, and clean and, when necessary and appropriate, sanitize all food contact
    surfaces of equipment and tools used as frequently as necessary to protect against contamination.
  • When appropriate, use EPA-approved products according to the label for cleaning and sanitizing.
  • Inconsistent adherence to or deviation from existing SOPs for cleaning and sanitizing by farms can
    affect produce safety. Effective communication on farms about SOPs and any changes to those
    SOPs can help ensure that food safety practices are being followed.
  • Root cause analyses may be useful in identifying for growers how human pathogen sources in the
    broader agricultural environment may contribute to contamination.
  • Improve traceability through increased digitization, interoperability, and standardization of
    traceability records which would expedite traceback and help remove contaminated product from
    the marketplace more quickly, thereby preventing further illnesses. This is not only important for
    growers, but also critical for shippers, manufactures, and retailers as well, to improve overall
    traceability throughout the supply chain.

Validating Consumer Cooking Instructions

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by Ryan Maus

Ready-to-eat (RTE) products are considered safe to consume without further cooking and are produced using controls such as thermal treatments that are validated to ensure that safe products are produced. However, non-ready-to-eat (NRTE) products may contain vegetative pathogens that require further cooking by the consumer to ensure that they are safe to consume. As such, cooking instructions provided by manufacturers should be validated to make sure that the NRTE product being cooked by the consumer provides the necessary lethality treatment to eliminate or reduce pathogen hazards to an acceptable level.


In 2006, FSIS issued notice 75-06 to their inspection program personnel to verify that establishments that produce certain uncooked and raw, breaded, boneless poultry products have adequate validation to support the cooking instructions that they include on the labels that will be applied to these products. FSIS has since provided guidance (FSIS-GD-2017-0017) for validation of cook instructions for these NRTE products. They also provide cook instruction validation guidance for mechanically tenderized beef products (FSIS-GD-2015-0022).

The FDA, unlike FSIS, does not have regulations addressing validation of cook instructions for NRTE products. However, the FDA fully expects NRTE products to be safe and products should contain labeling instructions related to safety (e.g., “keep refrigerated” or cooking instructions). Validation of cooking instructions by the manufacturer is a key step to ensure that products are safe when produced by consumers utilizing manufacturer’s preparation instructions. While guidance from FDA on cook instruction validation is lacking, trade associations such as the Consumer Brands Association (formerly the Grocery Manufacturer’s Association) and the American Frozen Food Institute do provide guidance.

Cook instruction validation begins with determining the appropriate lethality requirements. This can come from safe harbor time/temperature regulatory guidance, published scientific studies, and product-specific microbiological inactivation studies. The validation can then involve proving that the product meets a specific temperature after it is cooked (following the directions on the label) that meets safe harbor parameters. Or the validation may involve a microbial inactivation study, which may be more appropriate for products at greater risk of microbial contamination or those that achieve variable target temperatures
when following the cook instructions.

Factors affecting the validation include product packaging and the cooking device (e.g., microwave, stovetop oven, fryer) that can affect uniform heating of the product. Cold spots should be assessed and the amount of samples should account for variability among lots and be evaluated by a qualified individual. Cooking instructions should be reassessed when changes to ingredients and packaging occur. While validated cook instructions will provide assurance that microbial lethality requirements are met by the consumer, it should be noted that the consumer does not always follow the directions. This has led FSIS to propose declaring Salmonella an adulterant in breaded stuffed raw chicken products. Appropriate labeling or consumer education may be necessary to draw attention to the importance of following the cook instructions as they appear on the label.

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