Traceability Unwrapped: How Packaging Protects Every Bite

How to Find Listeria in a Food Facility

By Bob Lijana

Before you go looking for Listeria, you need to make sure that senior management across all functions is supportive of this task–especially when Listeria is found. Will someone (or some function such as QA) get blamed? Will enough resources be given? Will outward communications (e.g., to customers or FDA) be actively managed?

Or is the collective opinion “we do not need to know, because Listeria is surely not here”?

Most food companies make the correct strategic and ethical decision to test for Listeria. To that end, they typically test for the genus of Listeria species (L. spp.), and not specifically for Listeria monocytogenes (Lm). Thus, they do not end up with confirmation that Lm is present and therefore do not butt up against a regulatory zero-tolerance policy. But they get a strong indication that conditions are favorable to Listeria growth, so they can choose to assume that Lm is present and act accordingly. If corrective actions are taken to eliminate all Listeria, then one can justify that if Lm were present, it would be eradicated by these corrective actions.

Some companies test for a “marker organism” such as Listeria innocua. The thinking is the same as that above. This includes making the assumption that if Listeria innocua is found, then Lm may indeed also be present.

If your company has decided to look for Listeria, how do you go about doing so? The overall objective is to establish, validate, and execute an “environmental monitoring program” (EMP). Good starting points are the “Environmental Monitoring Handbook” published by 3M and Cornell University and a publication by the Institute of Food Technologists, “Design Elements of Listeria Environmental Monitoring Programs in Food Processing Facilities.” For seafood, the National Fisheries Institute has a publication on ready to eat seafood pathogen control.

Key to an effective EMP is sampling. Sampling is complicated to plan since the choices affect time and money. How many samples, where, and what are you sampling for (e.g., Lm, Listeria innocua, or L. spp.) ? These choices affect costs and how soon, or not, microbiological results are received. Random sampling never carries the day. Rather, sampling needs to be strategic—based on sound statistical principles, science, and your own assessment of what might really be going on.

Building a useful EMP is hard work, and requires a lot of patience and a lot of data. Listeria does not sit still–plant conditions change all the time. Hence, a positive sample today does not guarantee that there will be a positive sample tomorrow (especially when microbiology results take days to obtain). A good EMP finds growth niches and transfer points, and helps determine the overall risk for nearby food becoming contaminated.

In addition, actual as-made equipment design is incredibly important. Equipment not made hygienically, or that has been changed over time (“to make it work better”), may end up being a root-source of Lm. A good review of proper hygienic design can be found in “Food Safety Equipment Design Principles” by the Foundation for Meat & Poultry Research & Education.

Here are some effective approaches used in the food industry:

Bring in an expert third-party consultant or company to do the work for you.
Utilize the services of a certified and vetted microbiology lab, and partner with them.
Purchase best-practice software which models an EMP, and directs sampling for you.
Review the FDA and USDA guidance documents for direction–and then speak with your local regulators. (Yes, this is not without some risk.)
Conduct multiple “swab-a-thons” in your plant, sampling anywhere and everywhere to gather microbiological data. As mentioned above, it can be notoriously difficult to establish patterns of harborage and movement–but having hundreds of data points can at least give you a snapshot for the microbiological cleanliness of the plant. Note that this is time-consuming and costly, but could pay dividends if this is one of your only options.
Study, study, study. Map and analyze traffic patterns in the plant, evaluate water use and water flows (e.g., to and from drains), sample equipment around product zones, look at data from pre-operational activities, look at past microbiological sampling data, and talk with the sanitation team about what they see.

Note that it is generally not recommended to sample actual product given the regulatory consequences if Lm is found!

Regardless of the tactics chosen, Lm is typically hard to find in a “clean” plant. And determining where it comes from (i.e., the root source) is even harder. Microbial testing is still the best way to do this. Techniques such as ATP testing, total plate count or Enterobacter testing, and PCR-assay Listeria test kits can help guide you. But those results are only as good as the level of technical thinking that is brought to the them. One must truly evaluate where Listeria growth niches might be, regardless of how easy or hard it is to access those locations.

See the Related Articles below to read the series.

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August 12, 2025

Global Sustainability Regulations Impacting the Food Industry

By Harold Chase, MPH

In recent years, sustainability has emerged as a pivotal concern within the food industry, driven by growing consumer awareness and demand for environmentally responsible practices. As businesses strive to meet these expectations, global regulations play a crucial role in shaping sustainable practices across the sector.

Notably, the EU Green Claims Directive has introduced new guidelines that impact how food products in the region and imported are labeled and marketed, ensuring that claims about sustainability are credible and transparent. This directive not only aims to combat misleading marketing but also encourages companies to adopt genuine sustainable practices, ultimately promoting a more transparent and accountable food system. Food industry professionals must be knowledgeable and agile when it comes to global regulations in the EU, North America and beyond as they work to improve sustainability and remain competitive.

Legislative Status and Recent Developments

The Green Claims Directive proposal has not yet been adopted. During the legislative process, it underwent significant amendments and changes by the two EU co-legislators, the European Parliament and the Council of the European Union. Negotiations among them and the European Commission have been ongoing since the beginning of the year in the “trialogue” format.

Under industry pressure, they have agreed that third-party verification should take place within 30 days and may be extended, in duly justified cases, by an additional 30 days. In response to this industry concern, the Testing, Inspection and Certification (TIC) industry is developing solutions to efficiently address industry concerns.

The European Commission announced plans to withdraw the legislative proposal on environmental claims before the last trilogue, scheduled for June 23, 2025, citing pressure from several political groups that criticized the Directive for imposing an administrative burden on manufacturers.

Following the Commission’s announcement, negotiations were suspended. The Commission later indicated that it might proceed with the Directive if micro-enterprises were excluded from its scope, as per its initial proposal, which, however, contradicts the EU Council’s mandate.

The incoming Danish Presidency of the Council of the EU is expected to take over discussions on this issue after consultation with the three involved EU institutions. In the event of an agreement this year, the application of the directive cannot be expected to occur before 2028.

The EU Green Claims Directive

In line with the European Green Deal’s commitment to combat false environmental claims and reduce ‘greenwashing’, the legislative proposal aims to introduce minimum requirements for substantiating and communicating environmental claims in business-to-consumer practices. These claims must undergo accredited third-party verification before being used in commercial communications.

The proposed directive sets detailed rules for substantiating and communicating explicit environmental claims about products. These requirements would take precedence over Directive 2005/29/EC in the event of a conflict. The directive applies to voluntary, explicit environmental claims and environmental labeling schemes not regulated by other EU acts, such as the EU Ecolabel, the Organic Products Regulation, the Eco-Management and Audit Scheme (EMAS) or the carbon removals certification framework.

Food safety professionals should be familiar with the main elements of the initial proposal for requirements for Substantiating Claims, Comparative Environmental Claims and Communication of Environmental Claims:

Substantiating Claims: Includes specifying the product or company activity claims, taking a life-cycle perspective and considering all environmental impacts, and ensuring that positive achievements don’t have harmful impacts on climate change.
Comparative Environmental Claims: Requirements include using equivalent information and data for assessment, generating and sourcing data in an equivalent manner, and covering the same stages along the value chain.
Communication of Environmental Claims: Covers only substantiated claims and ensures that the provided product information is among the most relevant life-cycle stages.

The Commission would be empowered to adopt delegated acts to specify the information that can be communicated. The requirements do not apply to microenterprises (those with fewer than 10 employees and an annual turnover/balance sheet total of under €2 million) unless they request verification.

The proposed directive also sets requirements for environmental labeling schemes, certifying that a product, process, or company complies with environmental label requirements.

US Food Waste Reduction Laws

In the US, new laws have been developed, aiming to minimize food waste and its impact on supply chain management. With that, state legislators have been increasingly active and concerned about food waste. NSF is currently tracking 68 bills in the current state legislative sessions that address food waste, four of which have been signed into law.

One new law that impacts the food industry in Maine is set to take effect in 2030. The law defines a “designated food waste generator” and establishes a hierarchy of actions to be taken with the intention of reducing food waste, emphasizing three key points: reduction, donation and diversion for agricultural use or composting.

Colorado also implemented a new law that creates a voluntary program to assist small businesses in implementing food waste prevention and reduction strategies. The law requires the Department of Public Health and Environment to:

Provide annual training that includes strategies for preventing and reducing food waste.
Develop a food waste reduction guidance document.
Place the document on the department’s public website.
Update the document at least once a year.

The law also encourages grocery stores to clearly display the ingredients of prepared food items and use “best if used or frozen by” dates instead of “sell by” dates on prepared foods. Finally, the law extends existing civil and criminal immunity from liability for injury or death resulting from donated foods to include faith-based organizations that donate food and food donations to such organizations.

Another new law in Colorado encourages schools to adopt policies to reduce food waste in school cafeterias and food preparation facilities. The law also requires existing grant programs to consider providing funding to schools to develop and implement effective composting, excess food donation, or shared table programs.

The last of the four signed bills is in New York, which recently implemented a law that provides an additional year for the implementation of a program requiring entities that generate large amounts of food scraps to separate and donate food for human consumption to the extent possible and when donation is not possible, to engage with organic recyclers.

Food industry professionals must be knowledgeable about the various laws that take effect, so that they can comply with the requirements necessary to operate in different states.

Packaging Regulations

Packaging plays a critical role in the food industry’s environmental impact. It is no surprise that many states have enacted Extended Producer Responsibility (EPR) laws. California, Colorado, Maine, Oregon, New Jersey, Minnesota and Washington have all passed such laws, and many other states are considering EPR legislation. CA SB 54 was passed in 2022 and is perhaps the most comprehensive law of its kind in the United States. The law, which began phasing into effect this year, sets a goal of reducing plastic packaging by 25% by 2032.

The US FDA regulates food contact materials, including food packaging, as covered in 21 CFR. The CFR includes a list of substances that are prohibited from being used as food contact substances. With some limited exceptions, the FDA reviews all food contact materials, typically through the Food Contact Substance Notification process. This applies to packaging made from recycled materials, as the FDA requires manufacturers to demonstrate that these materials are safe for use in food contact applications.

Specifically, food industry professionals should be aware of relevant global food safety standards. ISO 18604:2013 is a mainstay in the industry, as it is an ISO standard that specifies the requirements for packaging to be recyclable. ISO 18604:2013 supports the United Nations Sustainable Development Goal (SDG) 12, Responsible Consumption and Production. In particular, this SDG sets a goal of halving food waste among businesses and consumers by 2030.

Sustainability for the Food Industry

Transparency in carbon emissions and reporting is crucial for food manufacturers to remain competitive in the industry. In fact, there are three different laws just in the state of California related to climate disclosure:

SB 253, the Climate Corporate Accountability Act: Applies to companies with total annual revenues exceeding $1 billion doing business in California, requiring disclosure of scope 1, 2, and 3 greenhouse gas emissions.
CA SB 261, the Climate-Related Financial Risk Act: Takes effect in 2026, requiring businesses that exceed $500 million in annual revenue to report on climate-related risks.
CA AB 1305, the Voluntary Carbon Market Disclosures Act: Requires entities making claims regarding net-zero emissions, carbon neutrality or significant reduction. In emissions to make specified website disclosures.

Beyond reporting, the nexus of food, water, and energy is crucial to maintaining our food supply and cannot go unstated. Water management is crucial in sustainable food production, as agriculture is the largest consumer of freshwater worldwide. Water is also intensively used in energy production. As we battle climate change, we may face challenges, as a shortage of water will not only impact our water sources but also strain our food production.

Adapting to Changing Global Regulations

As the global food industry continues to evolve, the imperative for sustainability has never been clearer. Increasing consumer awareness and regulatory pressures are driving businesses to adopt sustainable practices, making it essential for companies to reevaluate their operations and supply chains.

In this context, regulations play a pivotal role in fostering these changes, with the EU Green Claims Directive standing out as a significant force in shaping food labeling and marketing strategies. The EU Green Claims Directive not only aims to combat greenwashing but also sets a standard for transparency, compelling businesses to substantiate their sustainability claims.

As we delve into the current regulations impacting the food industry, including US states implementing laws that impact packaging and carbon emission transparency, it becomes evident that addressing challenges such as food waste, carbon footprints, packaging and water usage is not just a matter of compliance but a pathway to a more sustainable future.

August 12, 2025

Improving Audit Scores with Pest Management

By Nicole Keresztes James

Pests of all varieties pose a significant hazard to the food industry, as they can facilitate the spread of foodborne illnesses by serving as carriers of microorganisms that are the causative agents of these illnesses. Common pests include rodents, insects and birds; depending on geography and climate, other critters can be of concern. Pests contribute to foreign material contamination and adulteration, as they can easily spread disease-causing microorganisms and parasites through their droppings, urine, saliva and body parts. Contamination of food left behind by pests is also a significant source of consumer complaints and negative social media interactions, which can severely erode consumer trust in a company and/or brand.

A common cause of many food recalls is contamination by pests. In 2022, the Canadian Food Inspection Agency issued a recall of food products contaminated by Salmonella due to a rodent infestation. This recall impacted a significant portion of the country, including the western and central provinces. That same year, 400 Family Dollar stores temporarily closed across the US due to a rodent infestation in just one warehouse. In 2023, grocery chain Trader Joe’s recalled more than 10,000 cases of broccoli cheddar soup in seven states due to the presence of insects in the frozen broccoli florets in the soup.

Pest contamination can severely damage both a business’s bottom line and reputation, leading to impacts that can be as significant as bankruptcy or closure. Given the reputational damage that pests can cause, it’s important to remember that a proactive integrated pest management program (IPM) is the cornerstone of any facility’s good manufacturing or good distribution practices program. Mitigating the risks posed by pests can reduce customer complaints and potential recalls.

Common Pests and Their Risks

The most common types of pests in food settings include rodents, insects, birds and other critters specific to the environment and geographic location.

Rodents: Rats and mice are often the creatures that first come to mind when thinking about pests. Both can carry diseases that pose significant health risks to humans. The CDC lists a wide variety of diseases caused by viruses, parasites, and bacteria that are directly or indirectly carried by rodents. For example, Salmonella bacteria transmitted through rodent droppings can contaminate food products. In addition to contamination that can lead to foodborne diseases, rodents can contribute to visible foreign material contamination of food products and raw materials (which generally causes an overwhelmingly negative reaction in consumers of the products). They can even be the causative agent of health and safety risks to humans, as they can chew through electrical wiring, which then becomes a fire hazard.
Insects: Whether flying or crawling, insects can be problematic in food handling environments. Flies can contaminate food by carrying foodborne pathogens and may also end up as foreign material contaminants in products. For example, studies have shown that the human pathogenic microorganism E. coli O157:H7 is carried by flies of several species from cattle production areas to leafy green crop fields (Berry et al, 2019). Due to their frequent contact with organic waste materials, flies also transmit other pathogens, such as Salmonella enterica, Listeria monocytogenes, Klebsiella spp., and Campylobacter spp. (Shahanaz et al., 2025). Stored product pests, such as beetles and moths, can be a scourge in dry ingredient facilities, including flour mills. Multiple generations of these types of insects can have a cumulative impact on products and facilities over time, resulting in a loss of quality and quantity of the stored food items. Hardy ants and cockroaches are notoriously difficult to eradicate, requiring multiple treatment cycles and, in many cases, structural reconstruction to eliminate them from the facility. The US Food and Drug Administration classifies four types of cockroaches and two types of ants within their “dirty 22” species list due to their ability to spread foodborne illnesses and act as indicators of unsanitary conditions in food processing and storage facilities.
Birds: Research shows that there are more than 80 diseases, including Salmonellosis, that can be carried by problem birds such as pigeons and starlings. Birds can carry disease-spreading insects, such as fleas and ticks, while their waste material can teem with bacteria. Bird feces, feathers and nesting materials can fall into food products or onto food contact surfaces, causing direct and indirect contamination. Like rodents, birds can also cause significant damage to the structural integrity of a food facility through their nests and corrosive droppings.
Other critters: Depending on the location and type of environment the facility is in, other pests can be just as adept at entering and establishing themselves in a facility. For example, in warmer climates, reptiles and invertebrates not already discussed above can be included on the list of pests that a facility can be vulnerable to. The changing climate globally is also impacting the spread of various pests to areas of the world that have not yet encountered these species. With that in mind, it is even more crucial for food processing and storage facilities to adopt a highly proactive approach to pest management.

Mistakes in Pest Management

The main error that facilities make in their pest management strategy is to take a “hands-off” approach, particularly when they contract the management of pests to a third-party organization. In addition, other common mistakes include failing to update pest management plans and train employees regularly, failing to maintain detailed and up-to-date records, and not fully addressing identified areas of noncompliance. All these mistakes can lead to failed audits and, worse still, negative impacts on food safety.

Implementing a comprehensive, proactive pest management program is crucial for mitigating the risks associated with pests in food operations. The organization must have a skilled and trained internal team of pest control professionals or contract a reputable third-party pest control operator (PCO). Even with a reputable PCO by their side, organizations must still take responsibility for maintaining an open dialogue and partnership with that PCO, recognizing that it is not the PCO who is ultimately responsible for the safety and quality of the products going out to the market. Regardless of who is responsible for the service, failure to continually update the program and train those involved in the pest management protocols is a recipe for failure. Audit standards look not only for inspection records, but also for trending and completed corrective actions that include preventive measures. Not having these aspects of the records available will likely result in points lost during audits.

At the forefront of any well-managed pest management program are controls that ensure that pests are excluded from the premises. Gaps under and around doors and windows are among the most frequently cited nonconformities during audit visits. Other common citations include the mismanagement of pest devices, such as interior rodent devices, insect light traps and bait stations. Ensuring that employees are empowered to report concerns they observe regarding the facility’s structure and the devices placed around the premises is a tremendous asset to the success of the pest program.

Easy, Implementable Fixes

Mistakes may be unavoidable; however, several fixes can quickly support an organization with better pest management. First, establish a close working relationship between the facility’s leadership team and the pest management team, as well as any third-party providers. Frequent discussions about pest pressures, incidents, concerns and trends can help ward off potential issues and develop more proactive solutions.

Second, conduct ongoing surveillance by both the pest management team and properly trained internal personnel, through the checking of pest devices and inspecting the facility for signs of pest activity, entry points and infestation. Concurrently, seek out and implement accessible solutions for adequate documentation. Many pest control providers offer electronic monitoring systems that allow for easily retrievable details during reviews and inspections.

Third, train the facility’s workforce on pests and management strategies as a whole. Work with your PCO to ensure that employees are as up to date as possible on the pest protocols and techniques being used in the facility. Train employees to be vigilant about excluding pests, including those that may enter the facility through employees’ items, and to report any concerns they observe.

Meeting Audit Requirements

Audit standards are rooted in food safety and typically have expectations regarding the establishment and full implementation of a pest management program, including the expertise required, the techniques used, the monitoring completed and the corrective actions implemented. Indeed, one of the best ways to get “audit-ready” is to engage with a competent, licensed PCO. However, regardless of whether working with a third-party PCO or sourcing that competency and knowledge from within the organization, all facilities must remember that pest management is the responsibility of every employee at the facility. It will be through the support of the management team in the implementation of a proactive pest management program that builds on the cooperation of all individuals within the organization (and without, in the case of a third-party PCO) that a positive culture around the elimination of pest-related hazards and, by extension, positive outcomes during audits can be realized.

References

Occurrence of Escherichia coli O157:H7 in Pest Flies Captured in Leafy Greens Plots Grown Near a Beef Cattle Feedlot

Elaine D. Berry, James E. Wells, Lisa M. Durso, Kristina M. Friesen, James L. Bono, Trevor V. Suslow

Journal of Food Protection, volume 82, issue 8, August 1, 2019

Flies as Vectors of Foodborne Pathogens Through Food Animal Production: Factors Affecting Pathogen and Antimicrobial Resistance Transmission

Eshita Shahanaz, KirstenM. Zwally, Cameron Powers, Brandon Lyons, Phillip Kaufman, Giridhar Athrey, Thomas M. Taylor

Journal of Food Protection, volume 88, issue 7, June 23, 2025

August 12, 2025

From Field to Facility: Integrated Pest Management Strategies in Sustainable Agriculture

By Ellie Gabel

Integrated pest management (IPM) is often associated with the farming stages of food production. However, professional food manufacturers and food service providers must also adopt effective and budget-friendly sustainable pest management practices. Advancing technologies, an evolving regulatory framework and consumer expectations further underscore the importance of IPM, from farm to table.

The Evolution of Integrated Pest Management

Pest control in agriculture has evolved from heavy chemical applications to a safer, more ecologically sound, holistic approach. The toxins in those substances decrease microorganism abundance and diversity, which degrades fertile land for continuous yields. Meanwhile, stormwater runoff containing pesticides also harms ecosystems.

Modern practices emphasize a holistic approach with targeted intervention and monitoring to prevent infestations. IPM aligns with stricter compliance regulations so food professionals from farms to factories provide safe, high-quality goods while adopting environmental stewardship.

Holistic pest control is critical in agriculture. Researchers have found that they and disease result in a 30% yearly loss in cereal crops, a 54% loss in vegetable crops and a 78% loss in fruit crops. As the population grows, ensuring food security is of the essence.

Core Components of Effective IPM Strategies

Integrated pest management is not a single approach to controlling insects but the implementation of various insights, decisions, and actions to manage populations. These five components are critical to effective IPM.

Producers and facility professionals must identify which insects are present before developing an effective integrated pest management plan. Farmers in particular do not need to eradicate all living organisms. Some are beneficial to crops and even consume more damaging pests. Identification is necessary to make sound control decisions.

Monitoring

Today’s technologies — sensors, smart traps and data analytics — have improved how the sustainable agriculture and food industries monitor crops for pests. For instance, an electronic trap can detect insect bodies and wings, with one system achieving 98% and 86.7% accuracy for counting and classifying organisms, respectively. The devices can also collect and populate real-time data to help identify trends and hot spots.

Control

Professionals use various approaches to pest control, including biological, cultural, mechanical and chemical methods. Biological control relies on predators and pathogens to outcompete pests, while cultural techniques use special practices like reducing irrigation to reduce pest establishment. Mechanical controls entail trapping pests and rodents and directly blocking or removing them.

A final resort would be using chemicals, such as pesticides. However, because they are toxic, it is crucial to use them minimally to avoid harming humans, the environment and non-target specimens.

Prevention

Professionals should prevent pests through careful actions, such as avoiding ideal conditions for their establishment and survivability. This includes removing trash, stagnant water and overgrown vegetation. Growers should also rotate crops to promote better soil structure for healthier plants that can withstand damage.

Evaluation

Continuous evaluation of the IPM strategy is crucial to preventing future infestations in sustainable agriculture. This includes scheduling and maintaining records of inspections, updating training, and adjusting the plan as necessary. Prioritizing non-chemical prevention is also critical to enhancing safety and sustainability within the sector.

Successful IPM Implementation Across the Supply Chain

Integrated pest management is a cornerstone of sustainable agriculture that comprises rotating crops, planting pest-resistant varieties and boosting the presence of beneficial insects. These methods can reduce the amount of chemical pesticides necessary to control bugs.

However, farms are not the only places that need comprehensive IPM. The rest of the supply chain must also implement sound pest management to restrict and eliminate infestation. Professionals in food production facilities should protect the premises in the following ways:

Maintain the exteriors and avoid pest-attracting trees and shrubs.
Avoid mercury vapor and fluorescent lamp lighting that attracts flying insects.
Remove standing water and debris buildup around the premises.
Seal cracks, gaps, and other openings around the facility’s foundation, windows and doors.
Install screens over vents and exhaust ducts.
Clean spills and food droppings immediately.
Adhere to proper storage methods of products and equipment.
Regularly inspect the building and all incoming and outbound trailers.

Production facilities must also remain at the appropriate temperature to ward off insects. Workers should stay vigilant and look for bugs in refrigerated storage. Food service operators can partner with suppliers that follow stringent IPM measures to ensure pest-free, traceable ingredients.

Cleaning spills and food debris off of floors is crucial to avoid attracting pests in food processing plants

Regulatory and Certification Landscape

Producers and food manufacturers must follow several food safety regulations and practices. For instance, good protocols guide employees in proper sanitation and hygiene to ensure quality assurance and public health, including isolating pests in facilities. Other compliance rules and certifications include the Safe Quality Food (SQF) standards, the Food Safety Modernization Act (FSMA), and GlobalG.A.P., which aim to reduce contamination risks.

For instance, the SQF defines vermin as rodents, insects, and birds that carry diseases and threaten food, feed, and packaging. It then lists processes professionals can implement to meet quality food benchmarks. Meanwhile, GlobalG.A.P. comprises voluntary standards farmers can implement for a safer, more sustainable food market, while the U.S. Food and Drug Administration’s FSMA ensures accountability throughout the food supply chain.

The Business Value of Holistic, Sustainable Pest Management

IPM strategies are as effective for business success as they are for food safety. By ramping up robust pest control post-harvest, industry players can produce higher-value products for customers and secure their bottom line.

August 11, 2025

The Gray Zone of Insecticide Repellency: Revisiting Long-Held Assumptions About Pyrethroid Effects on Pests

By Alvaro Romero, Ph.D.

Insecticide efficacy is often equated with direct mortality — but that’s only part of the story. Some compounds, especially neurotoxic insecticides like pyrethroids, produce sublethal effects that disrupt pest behavior and physiology without causing immediate death. These responses may include irritancy, hyperactivity, avoidance, mating disruption, or interference with aggregation and feeding behavior. Sublethal exposure could impact a pest’s ability to mate and pass on its genes. While the pest may be alive, the product has “removed” the pest from their ultimate biological goal of reproduction.

In mosquito control, sublethal exposure to pyrethroids can trigger behavioral changes — either through detection of insecticides at a distance (repellency) or agitation after contact (irritancy) —both of which can reduce human-vector contact. While these categories often overlap, it is useful to distinguish between them: repellency involves sensory-driven avoidance without contact, typically mediated by olfactory receptors in the antennae, whereas irritancy results from neurotoxic effects that provoke escape responses after contact.

Among these sublethal responses, spatial repellency plays a particularly important role in mosquito management. Volatile insecticides delivered via spatial sprays or emanators create an airborne barrier that discourages mosquitoes from entering or remaining in treated areas. For pests such as termites, ants, cockroaches, bed bugs, and other occasional invaders, sublethal responses to insecticides are often viewed as problematic. It is commonly—but incorrectly—assumed that these pests can reliably detect and avoid treated surfaces. In reality, predictable and consistent repellency is primarily observed in subterranean termites. Although ants are often believed to avoid insecticide-treated areas, studies show that they typically continue foraging over such surfaces, suggesting that true repellency does not apply. For most other pests, behavioral responses to insecticides vary depending on species, physiology, environmental context, and product formulation. Below, we explore how these sublethal effects influence outcomes for key urban pests when exposed to pyrethroids.

Not So Repelled: Why German Cockroaches Still Cross the Line

German cockroaches offer a compelling example of how sublethal insecticide effects can challenge traditional assumptions about repellency. Pyrethroids are widely considered to provoke strong and predictable behavioral responses, including repellency. However, recent studies under controlled laboratory conditions have demonstrated that German cockroaches still make contact with pyrethroid-treated surfaces—contradicting the common belief that these compounds are strongly repellent. This finding is consistent with the low volatility of many pyrethroids, which limits their potential to exert true spatial repellency. These observations have led to the suggestion that placing cockroach gel baits on or near pyrethroid-treated surfaces may not diminish bait effectiveness, as cockroaches appear to continue foraging over treated areas. While contact with pyrethroids can produce an irritant effect that prompts temporary retreat or relocation to untreated zones, cockroaches often resume nocturnal activity and may re-encounter treated surfaces or nearby baits, resulting in continued exposure. More research is needed, particularly on formulations that combine neonicotinoids with pyrethroids, to better understand how these chemistries interact to influence contact irritancy, avoidance behavior, and foraging dynamics in cockroaches under both laboratory and field conditions.

Termites: A Distinct Case of Ground-Level Repellency

Termites are one of the few pest groups that consistently demonstrate true repellency to some insecticides—especially pyrethroids like permethrin, bifenthrin, and cypermethrin. Numerous studies have shown that subterranean termites actively avoid soil treated with these compounds, altering their tunneling behavior or abandoning the area entirely. This reliable avoidance response plays a key role in forming chemical barriers that protect structures by preventing termite entry. Because of this consistent behavior, pyrethroid-based termiticides have long been marketed and used as repellent soil treatments, in contrast to non-repellent options like fipronil or imidacloprid, which termites unknowingly traverse, enabling colony-level suppression through horizontal transfer.

Ants: A Case Where “Repellency” Doesn’t Apply

The commonly held belief that pyrethroids always act as repellents has been challenged in ants, with research showing that foraging individuals do not actively avoid pyrethroid-treated surfaces. Although ants are highly sensitive to chemical cues and communicate extensively through pheromones, studies have demonstrated that ants continue to behave normally—following trails and foraging—even after stepping onto treated areas. The perceived “repellency” in some cases likely results not from active avoidance, but from the insecticide killing foragers before trails are firmly established. Field trials, such as those involving Argentine ants and bifenthrin-treated panels, further support this: ants continued to cross treated surfaces and died within minutes, without evidence of behavioral avoidance. These findings suggest that pyrethroids can be used effectively against ants in perimeter applications, provided formulations are applied strategically to zones of activity.

A similar response might be expected in other occasional invaders—such as scorpions (Fig. 1), stink bugs, lady beetles, boxelder bugs, ground beetles, earwigs, crickets, and sowbugs—which often move along treated structural edges and surfaces both around buildings and when entering indoor spaces. While further research is needed to better characterize the behavioral responses of these pests to pyrethroid-based formulations, leveraging the contact-based exposure observed in ants could improve the overall effectiveness of insecticide applications in both indoor and outdoor general pest management programs.

Conclusion: Rethinking Repellency in Pest Control

The idea that pyrethroids universally repel pests is an oversimplification. As this review shows, true and predictable repellency is largely limited to subterranean termites, whose soil-foraging behavior makes them uniquely sensitive to pyrethroid-treated zones. For other pests—including ants, cockroaches, bed bugs, and occasional invaders—behavioral responses to pyrethroids are far more nuanced. Many species do not actively avoid treated surfaces, and in some cases, sublethal effects such as agitation or increased mobility may even enhance exposure to insecticides or drive pests toward strategically placed control tools like baits or dusts.

Recognizing the complexity of these sublethal responses is essential for developing effective, pest-specific strategies. Rather than treating repellency as an all-or-nothing phenomenon, pest management professionals should consider how formulation type, application strategy, and environmental context influence pest behavior. When approached thoughtfully, sublethal effects—often seen as limitations—can instead be leveraged as assets, helping to improve outcomes across a range of urban pest control programs. This may be especially true for occasional invaders, where non-repellency can promote greater contact with treated surfaces and increase the likelihood of effective control.

Pest Management Webinar: Innovating for Unmatched Roach Control in Every Environment

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References

Haynes, K. F. (1988). Sublethal effects of neurotoxic insecticides on insect behavior. Annual Review of Entomology, 33, 149–168. https://doi.org/10.1146/annurev.en.33.010188.001053
Moore, D. J., & Miller, D. M. (2006). Laboratory evaluation of insecticide product efficacy for control of Cimex lectularius. Journal of Economic Entomology, 2080–2086.
Romero, A., Potter, M. F., & Haynes, K. F. (2009). Behavioral responses of the bed bug to insecticide residues. Journal of Medical Entomology, 46, 51–57.
Thanispong, K., Achee, N. L., Bangs, M. J., Grieco, J. P., Suwonkerd, W., Prabaripai, A., & Chareonviriyaphap, T. (2009). Irritancy and repellency behavioral responses of three strains of Aedes aegypti exposed to DDT and α-cypermethrin. Journal of Medical Entomology, 46, 1407–1414
FMC Australasia. (2021). Repellents vs Non-Repellents: It’s Not All Black and White. FMC Corporation educational brochure. © FMC Australasia
Romero, A., Agnew, J., Paysen, E., & Blakely, B. (2021, October 19). Arizona bark scorpions and their responses to insecticides. PCT Convention Extra 2021. https://www.pctonline.com/article/arizona-bark-scorpions-and-their-responses-to-insecticides/
Gaire, S., Gondhalekar, A. D., & Scharf, M. E. (2024). Behavioral responses of field‐collected German cockroaches to pyrethroids and implications for resistance management. Pest Management Science, 80, 4323-441.

August 7, 2025

Texas A&M Researchers Study Diet’s Impact On Salmonella Prevalence In Cattle

By Megan Bennett

Salmonella is one of the leading causes of foodborne illnesses in the United States, according to the Centers for Disease Control and Prevention, and can spread to people from a variety of foods, including beef. Understanding how and why cattle become infected with Salmonella is an important part of fighting this major public health concern.

Researchers at the Texas A&M College of Veterinary Medicine and Biomedical Sciences (VMBS) are addressing this problem from a new angle by studying how diet and feeding schedule impact Salmonella infections in cattle.

Their recent study, published in the American Society for Microbiology’s Microbiology Spectrum journal, found that high-starch diets can potentially lower Salmonella prevalence in cattle, especially within the lymph nodes — organs that are often embedded in fat trims included in ground beef products.

“Lymph nodes may be present in fat trimmings that are used to balance lean-to-fat ratios in ground beef products,” said Yesica Botero, a fourth-year biomedical sciences Ph.D. student. “This is a food safety concern because Salmonella can hide inside lymph nodes, where surface cleaning or treatments do not reach. As a result, it can still be present in ground beef.”

Feedyard cattle are typically fed a high-energy, grain-based diet designed to promote rapid growth and efficient weight gain.

Understanding the role that a high-starch diet potentially plays in reducing Salmonella prevalence could have major impacts on the beef cattle industry, providing ranchers with new options for controlling the spread of bacteria within their herds.

Taking A New Approach

The Texas A&M project was designed to study feedlot cattle that Dr. Kendall Samuelson, from West Texas A&M University, was examining in a separate project to see whether high-starch diets and feeding schedules impact liver abscess formation.

“We aimed to understand the factors that contribute to the presence and distribution of salmonella in feedlot cattle,” said Dr. Gizem Levent, a VMBS assistant professor in the Department of Veterinary Integrative Biosciences. “There aren’t many studies focusing on understanding how diet and management changes impact Salmonella.”

Botero and Levent took samples of feces, hides, lymph nodes and soil from Samuelson’s cattle pens over a period of more than seven months. They found that while there was little difference in Salmonella populations between cattle with scheduled versus erratic feedings, the level of starch in the diet made a notable impact.

“We saw a reduction in Salmonella, especially in the lymph nodes, when cattle were fed a high-starch diet,” Botero said. “High-starch diets typically cause a lower pH in the rumen, which may be what reduces Salmonella prevalence in the gastrointestinal tract and, subsequently, in lymph nodes.

“Findings from Dr. Samuelson’s original study suggested that high-starch diets may also correlate with a higher incidence of liver abscesses,” she said. “This is something we would like to explore further in upcoming studies by testing different starch concentrations in the diet to find one that does not harm cattle health — such as by increasing the risk of liver abscesses — but still helps lower Salmonella levels.”

Continuing The Investigation

In addition to studying how different levels of starch impact liver abscesses and Salmonella, Levent and Botero are planning to dive even deeper into the data to study the specific serotypes, or genetic profiles of Salmonella, observed in their samples.

“We want to do a follow-up study with more in-depth analysis of the dynamics of the Salmonella population,” Botero said. “By looking at the genetic profiles, we can better understand which serotypes are present, how they might respond to antibiotics, and whether they carry genes that make them more likely to survive or spread in the environment.”

Fortunately, what they have seen so far from the feedlot samples does not indicate a high presence of Salmonella or serotypes resistant to antibiotics.

“The overall Salmonella population found was not resistant to antibiotics of public health concern, which is good news for public health,” Levent said. “But we will definitely keep screening for resistance so that we can better understand what makes resistant populations exist in the environment.”

July 15, 2025

Heavy Metals in Rice and Leafy Greens: Paths to Reductions

By Neal Saab, PhD

Some food contaminants arise from natural or agricultural environments where crops are grown. Examples include heavy metals which are sometimes present in leafy greens like spinach and grains like rice. If concentrations of these and other heavy metals exceed certain thresholds they can pose risks to public health, especially in younger populations. Both food groups are critical components of nutritious and wholesome diets. But the risks posed by sometimes significant levels of heavy metals are giving health experts pause and prompting new research into how to reduce potential risks in vegetables and grains without reducing or eliminating these healthy foods from diets.

The sensitivity of children to heavy metals/toxic elements has led the U.S. Food and Drug Administration to establish a ‘Closer to Zero’ initiative to reduce them in the food supply. This often involves addressing important food groups like vegetables and rice.

Leafy greens like spinach, kale and lettuce can absorb metals like cadmium and lead which are often naturally found in the soil. But they do so in different ways and in different parts of the plant. And the potential for arsenic to accumulate in rice under certain growing conditions is leading researchers to explore steps both farmers and home cooks can take to reduce the metals’ presence.

One study led by Dr. Angelia Seyfferth at the University of Delaware and supported by the food safety and nutrition research nonprofit IAFNS uses spinach to compare and contrast how cadmium and lead differ in how they move through soil and accumulate in plant foods. The paper also discusses practical pre- and post-harvest techniques to reduce human exposure to these metals that can be adopted by farmers, food processors and consumers.

The study, “Mitigating Toxic Metal Exposure Through Leafy Greens: A Comprehensive Review Contrasting Cadmium and Lead in Spinach,”¹ appears in the peer-reviewed journal GeoHealth. This review highlights differences in the magnitude of exposure, bioavailability, and the practicality of mitigation strategies and calls for more research on cutting chloride inputs to leafy green crops like spinach, kale and lettuce to reduce plant uptake of cadmium.

According to the authors, “It is paramount to understand the soil and plant factors that dictate contaminant accumulation in edible tissues to identify mitigation strategies for metals in foods.”

They recommend action during both crop cultivation and product processing. “Pre-harvest techniques are generally actionable by the grower and include soil preparations and amendments, irrigation practices, and cultivar selection. Post-harvest techniques are further downstream and include spinach handling in the field, washing either by a factory or by the consumer, and other consumer-driven choices regarding diets.” The paper also looks at mitigation steps for lead and other metals in several crops.

Alternative Cultivation

Another study supported by IAFNS in the journal Science of Food finds that alternative cultivation practices that reduce water use may reduce greenhouse gas emissions and arsenic concentrations in rice crops but may inadvertently also boost levels of cadmium in rice plants. That paper, Unintended Food Safety Impacts of Agricultural Circular Economies², with Case Studies in Arsenic and Mycotoxins, makes several findings.

For example, continually flooded rice paddy production — the traditional method of producing rice — boosts arsenic levels in rice. But alternate wetting-drying rice production reduces the risk of arsenic uptake from soil. However, dryer soils may lead to greater uptake of cadmium in crop plants. The authors remind readers that alternative cultivation practices are not all-or-nothing strategies. For example, rice farmers often carefully weigh the specific amount of flooding and dry field management in a manner that optimally reduces both arsenic and cadmium uptake by their crops.

A third IAFNS study, Agronomic Solutions to Decrease Arsenic Concentrations in Rice³, suggests that the most effective treatments for reducing levels of the toxic metal arsenic in rice are cultivar selection, irrigation management, cooking approach and the application of selenium or silicon soil amendments. This research appears in a recent article “Reducing the Risk of Arsenic in Rice” in Food Safety Tech. The article pointed out that both farmers and home cooks can take steps to reduce arsenic.

Postharvest Techniques

Partially cooking and drying the rice is known to reduce arsenic. Rinsing, soaking and disposing of the leftover water are viable methods of reducing arsenic for home cooks. For example, cooking methods that involve briefly parboiling rice (partially cooking in boiling water before finishing by steaming or other methods) and discarding the parboiled water lowered levels of arsenic up to 83%.

The presence of heavy metals in healthy foods like leafy greens and rice pose potential public health challenges and require creative research, analysis, and engagement with stakeholders throughout the supply chain. New research is identifying workable solutions to this issue that can be applied by all stakeholders from growers to consumers. IAFNS is proud to catalyze new science that is mitigating the risks of toxic metals in foods.

References

¹ Seyfferth, A.L., Limmer, M.A., Runkle, B.R.K., Chaney, R.L. (2024). Mitigating toxic metal exposure through leafy greens: A comprehensive review contrasting cadmium and lead in spinach. GeoHealth, 8(6). https://doi.org/10.1029/2024GH001081

² Scott, C.K., Wu, F. (2024). Unintended food safety impacts of agricultural circular economies, with case studies in arsenic and mycotoxins. Science of Food, 8(52). https://doi.org/10.1038/s41538-024-00293-8

³ Leavitt, M.E., Reba, M.L., Seyfferth, A.L., Runkle, B.R.K. (2025). Agronomic solutions to decrease arsenic concentrations in rice. Environmental Geochemistry & Health, 47(209). https://doi.org/10.1007/s10653-025-02508-7

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July 14, 2025

Where Listeria Comes From, and How it Moves Around

By Bob Lijana

Listeria is widely distributed in nature, found in soil, water, vegetation, and animal feces. And since it can be found in soil, it has the ability to contaminate vegetables and produce grown in that soil. This can also occur if contaminated manure is used as fertilizer.

Thus, it is quite easy for Listeria to get into a food plant on someone’s shoes, or equipment being brought in from outside, or ingredients coming from a supplier.

Given the ubiquity of Listeria, a good food safety team (and their management) always assumes that the organism is present somewhere in the plant. Even with regular microbiological sampling coming up negative (i.e., no Listeria found), that is not a reason to lower the level of vigilance. Ever.

The insidious nature of Listeria is such that it can hide, even in untoward conditions, and it can be moved around, up, down, and sideways. The same factors which allow Listeria to enter a plant allow it to be transported within that plant.

Let’s talk about “harborages” and “movement vectors.”

Harborages are all areas in a plant which have the necessary conditions for Listeria to grow. Biofilms (resistant coatings which protect the organism) can offer an additional level of security for the organism. Listeria may or may not grow, but it can certainly survive. These areas (e.g., underneath equipment, in drains) are also called “growth niches” in the scientific literature.

Movement vectors are those locations in which harborages intersect with people and equipment moving around the plant. These are the opportunities for Listeria to move. These points (e.g., a fork truck running through contaminated water) are also called “transfer points” in the scientific literature. An example:

An employee accidentally drops Listeria-laden potatoes on the floor.
The employee walks through those potatoes and across another production line to get a stainless steel scoop to clean up the potatoes.
The employee walks back through the clean production line to scoop up the dirty potatoes, throw them in a trash container, and then put the scoop back.
Another employee, not observing any of this, picks up that scoop later to sample ready to eat potato salad.

As you can infer, unbeknownst to the employees, the potatoes were harborages for Listeria, and the scoop (and footwear) were movement vectors likely resulting in Listeria getting into food.

Now think about all of the movement and travel of people and equipment that occurs in your own plant. You may even see the following:

Fork trucks moving pallets from a warehouse to a product zone.
Stainless steel carts wheeled from one line to another.
Production operators carrying ingredients from one line to another.
Maintenance tool boxes being set on the floor, and then carried to another location.
Mixing implements being used and then hung for ready use later without being cleaned.
Bowls containing work-in-progress being wheeled across production lines on their way to a cooler.
Employees leaving their production line to get to a break area by walking across other production lines that use different allergens than theirs.

Best practices for Listeria control necessitate that harborages are eliminated and movement vectors are identified and controlled. Attacking Listeria in this way can reduce food safety risk dramatically. Note that the root source is almost assuredly a harborage site (a hiding spot for Listeria). So one of the best ways to find that harborage site is by identifying and mapping movement in the plant. Then follow the movement backwards and forwards, and up and down. You may find yourself surprised at where water can run or come from. And therein lie the “eureka” moments.

The objective is to identify the true root source of the Listeria, and eliminate it. This is very different than simply finding some Listeria and tossing sanitizer on it—this is very common, and people are lulled into believing that the Listeria has now been controlled. This is hardly ever the case if the root source has not been eliminated and if the movement vectors have not been identified and actively managed.

See the Related Articles below to read the series.

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July 12, 2025

Listeria-related Regulations, FDA & USDA

By Bob Lijana