The United States Food and Drug Administration (FDA), in collaboration with federal, state, and local partners, identifies, responds to, and prevents outbreaks linked to FDA-regulated products. If FDA determines a firm is not in compliance with applicable FDA requirements, the firm may be informed through a Warning Letter (WL). This study provides an overview of the WLs issued to firms that were involved in FDA-led multistate foodborne outbreak investigations. WLs, issued from January 2018 through August 2023, were obtained from the FDA.gov website. Twenty-two of these WLs were issued to domestic firms after the conclusion of foodborne outbreak investigations. Forty-six regulatory citations were identified across the WLs, with 1-8 violations per WL. Microbial pathogens accounted for the food safety hazards cited in all but one letter, with Salmonella representing the majority of hazards. Two citations were issued most frequently: deficiencies in Foreign Supplier Verification Plans, and failure to identify and evaluate hazards requiring a preventive control. FDA is committed to protecting the nation's food supply, and WLs help achieve prompt voluntary compliance. Understanding the regulatory violations identified during outbreak investigations may help the food industry and regulators alike focus prevention efforts and reduce the burden of foodborne illness.

Surface sanitation is used to mitigate the transmission of infectious agents and is the collective process of washing a surface then rinsing it with potable water to remove debris and residual cleaning agent. If necessary and depending on surface type, contamination event, or regulatory requirement, an antimicrobial agent (chemical sanitizer or disinfectant) registered with the Environmental Protection Agency or heat (steam or hot water) can be applied to the surface to reduce or inactivate pathogenic microorganisms. The absence of universally defined terms and regulations pertaining to the various stages of surface sanitation has resulted in confusion, potentially leading to inadequate sanitation practices and persistent surface contamination. We addressed this issue by raising awareness of the significance of surface cleaning and elucidating the fundamental principles, key considerations, and potential areas for improvement concerning surface cleaning. Specific topics covered include a comprehensive description of surface cleaning, barriers hindering effective surface cleaning, correlation between contamination and foodborne disease outbreaks, and variations among cleaning agents. To maintain conciseness and relevance, the exclusive focus is on hard, nonporous surfaces, which have been identified as potential sources for the transmission of pathogenic microorganisms associated with foodborne illnesses.

Foodborne poisoning from mushroom consumption remains a critical food safety concern. An outbreak of mushroom poisoning in Montana in 2023 was linked to morel mushrooms imported from China. After eating at a restaurant in Montana, 51 people experienced gastrointestinal illness, resulting in three hospitalizations and two deaths,. Ultimately, the outbreak was linked to the consumption of undercooked and raw morel mushrooms, highlighting the importance of proper cooking to reduce toxin levels and mitigate the risk of illness. Concerns regarding potential harmful effects of consuming raw morels suggest the need for increased awareness and caution among consumers and restaurants. Relevant food safety recommendations since the outbreak occurred have become publicly available, including messaging to avoid the consumption of raw morels and thorough cooking of these mushrooms. The investigation revealed industry knowledge gaps in the safe preparation of morel mushrooms, shedding light on the impact of inadequate food safety measures. Regulatory guidance, voluntary labeling information, and further outreach to consumers promoting awareness and use of publicly available cooking advice may enhance awareness and safety regarding consumption of morel mushrooms.

Salmonella is a significant threat to human health, causing an estimated 1.35 million illnesses each year in the United States. There is increasing consensus that regulatory strategies and industry efforts that target serovars of public health concern are essential to reduce human salmonellosis, and it is important to understand the data available to assess serovar distribution among food sources. We analyzed isolate data from 2015 to 2020 for 21 serovars common in food animals in public data sets available through the Food Safety and Inspection Service (FSIS) and National Center for Biotechnology Information Pathogen Detection database (NCBI PD). Following defined criteria, we obtained metadata from 7,812 and 12,248 Salmonella isolates on the NCBI and FSIS websites, respectively. Our analyses found significant differences in serovar distribution between (i) FSIS data and NCBI data contributed by non-FSIS sources and between (ii) different isolation sources for a commodity. Specifically, we found isolation patterns of certain serovars (e.g., Salmonella Infantis) coincided with reported outbreaks, and more serovars were overrepresented in the NCBI PD data set. Although our results suggest biases in Salmonella serovar distribution sets, we found consistent trends across data sets that indicate the value of public data sets for informing future subtype-specific Salmonella regulations and control efforts.

Chlorine and peroxyacetic acid (PAA) are widely used throughout the food industry as economical and effective sanitizers. However, efficacy is partially dependent on proper storage conditions, as they are affected by UV light exposure, temperature, and pH, but the degree to which these factors influence sanitizer effectiveness has not been well described. This study examined the effects of plastic bottle type (transparent or opaque) and storage conditions on chlorine (200 ppm of free chlorine) and PAA (60 to 80 ppm) concentrations. Bottles were stored in outdoor, indoor, or refrigerated conditions, and sanitizer concentrations were measured over a 32-day period (summer 2022). Although bottle type significantly affected chlorine stability, it did not result in a significant reduction in PAA concentration. The free chlorine concentration in sanitizers stored in translucent bottles was depleted by day 4 of outdoor storage and ca. 50 ppm by day 13 when stored at room temperature. PAA concentrations stored outdoors or at room temperature ranged from ca. 0 to 30 ppm by day 32. Both sanitizer concentrations remained consistent under refrigeration for all bottle types through the 32-day period. Proper storage and monitoring of sanitizer can ensure adequate microbial reduction when used in food handling environments.

With the surge in popularity of kombucha tea, there has been a growing trend of individuals brewing this beverage at home. However, no consumer recipes have been evaluated by food safety Extension specialists for safety and quality. The present study aimed to determine critical food safety factors necessary for safely homebrewing kombucha. Kombucha was prepared with commercial Symbiotic Culture of Bacteria and Yeasts (SCOBY) and sugar concentrations of 26 g/L, 53 g/L, and 80 g/L prior to inoculation with surrogate organisms Escherichia coli K12, avirulent Salmonella strain (Salmonella Typhimurium strain LT2, H2S+), or Listeria innocua to yield nine treatment conditions per replicate, for a total of three replicates. Surrogate populations, titratable acidity of acetic acid (TA), and pH were monitored on Day 0, 7, and 14 of fermentation. TA increased (p<0.001) and pH decreased (p<0.001) from Day 0 to 14 for all treatments. The total mean log reductions across time period and sugar concentration observed for E. coli, Salmonella, and Listeria populations were 5.02, 5.86, and 4.26 log CFU/ mL, respectively. These findings will be used to inform a validated consumer recipe and corresponding guidance for safely brewing kombucha at home.

Since the early 1990s, microbial modeling has become an increasingly important part of commercial food preparation and manufacturing. Using mathematical techniques and carefully designed experiments, one can make models to predict microbial growth, survival, or death and use those predictions to formulate and process foods efficiently and with minimal food safety risk. Today, many models exist in both public and private domains. However, they may not be used to their fullest potential for various reasons. One suggested reason is uncertainty over potential liability associated with their use if adverse consequences were to occur. A panel of five individuals representing academic, industry, regulatory, and law professions discussed various perspectives on this topic including risk management, the interplay between challenge studies and microbial models, and liability. The common theme was the critical importance of designing and using models responsibly. This careful use includes being explicit about and documenting assumptions, validating models for accuracy in relevant conditions, and documenting decisions based on model outputs. Decisions should be reviewed against the question “would 12 jurors think that this is a reasonable decision?” If the answer is “no,” then it is time to reconsider the decision.

Salmonella is of concern in the fresh produce sector, and a recent outbreak of Salmonella infections was associated with baby cucumbers in Australia. Some consumers advocate peeling cucumbers to improve food safety. We investigated the transfer of Salmonella Typhimurium (n = 2) and Salmonella Newport (n = 1) from unrinsed and rinsed cucumber skin to flesh and peelers (stainless steel or plastic) during peeling of baby cucumbers. Levels of Salmonella attached to cucumbers were ~7.64 to 7.87 log CFU/g (unrinsed) and ~6.75 to 7.40 log CFU/g (rinsed). Levels of Salmonella Typhimurium transferred onto the flesh were higher (~0.1 to 1.8 log %) than those of Salmonella Newport (~-1.7 to 1.4 log %) irrespective of rinsing prior to peeling. Levels of Salmonella transferred to the stainless steel peeler were generally lower (~-3.62 to 1.58 log %) than those transferred to the plastic peeler (~−3.74 to −0.52 log %). Rinsing reduced attachment of Salmonella tounpeeled cucumber (~0.50 to 1.00 log CFU/g) and reducedtransfer to the flesh (~−1.71 to 1.11 log %) and peelers(~−3.71 to −1.42 log %). Salmonella strains and peeler material may contribute to the degree of transfer. Stainless steel peelers may be a better option for consumers, but use of these peelers does not eliminate the risk of Salmonella transfer during peeling.

Wild birds can be serious pests on farms by damaging produce and introducing food safety hazards to production fields and packinghouses. The most serious crop damage is usually caused by fruit- or seed-eating species such as blackbirds, cardinals, robins, or crows, whereas other species such as sparrows, finches, and starlings can take up residence in farm buildings and quickly become a nuisance. Creating an effective management plan to deter wild birds from fields and buildings begins with correctly identifying bird species and the damage that they are likely to cause. Just as different kinds of pest insects target different plants at different times of the year, not all birds feed in the same way, nor at the same time. Targeting deterrence strategies toward specific species is more cost-effective than a “catch-all” approach and reduces the likelihood that nontarget species are affected. The most effective management plan will be targeted toward specific problem species at specific times of year and may involve mixing and matching different deterrence strategies.

Top icing of produce is a practice used to preserve freshness and extend shelf life during transport and storage for some fresh produce items. However, there are concerns about possible food safety risks associated with this practice, especially regarding managing ice water and the potential for cross-contamination in distribution centers and warehouses. Food safety regulations such as the U.S. Food and Drug Administration’s Preventive Controls for Human Food rule require distribution centers and warehouses to evaluate hazards and identify those that need a preventive control as defined in the rule. Here, we outline how to evaluate and manage risks associated with top icing. Each operation should assess potential hazards associated with the commodity, facility, and management practices to determine if they are adequately managed as Good Manufacturing Practices or require the implementation of preventive controls within a food safety plan. Facilities should assess risks of receiving, handling, and storing top-iced produce, including supplier programs, potential cross-contamination points, pallet stacking, and slotting procedures, among others. Risk-based measures can be implemented to reduce food safety concerns associated with top-iced produce. These measures include transitioning to iceless produce, maintaining cold temperatures, single stacking produce pallets, establishing dedicated wet rooms, implementing drainage systems, shrouding or adding liners under pallets, and implementing appropriate cleaning and sanitizing schedules.