Rodent Control in the food supply chain

Did you know that rodents are the most damaging pests to agriculture, horticulture, forestry, and public goods? A recent example might shed light on the sheer amount of damage these critters can cause. Recently, the value-store chain Family Dollar temporarily closed more than 400 stores in Arkansas after discovering a rodent infestation. After these persistent rodent infestations, there was an active recall of food, dietary supplements, cosmetics, and products. The authorities found live and dead rodents and a history of pest activity, with company records indicating the collection of more than 2,300 rodents over a period of 6 months. Yikes!

What is Rodent Control?

Rats and Mice are prolific breeders. They have about six litters yearly, and each litter can include as many as ten pups. You can only imagine the collective damage that many rodents can cause, be it property and food damage, or contamination to humans, livestock, and wildlife. Rodent Control is how we reduce the negative impact of these tiny but mighty creatures. There are many steps involved, which will be touched upon later in this guide, but in short, a successful rodent control program integrates rodent inspections, rodent exclusion, and sanitation measures. The rodent control solution offered would be specific to each scenario.

The Food Supply Chain

The example you read in the beginning about the Family Dollar Chain constitutes rodent infestation in only one part of the food supply chain. “What is a food supply chain?” you might wonder. A food supply chain refers to the sequence of processes that enable food from a farm to end up on our tables. These processes include food production, processing, distribution, consumption, and disposal.

The farmer is the key, who can be considered an engine kickstarting the whole process, by providing the raw material, for example, produce or meat. Before the food reaches a supermarket or grocery, it will be sent to a manufacturing or processing plant where it is unloaded, processed, and packaged. It then moves to a warehouse where it waits, ready for shipment before finally being trucked to the supermarket where it reaches our hands.

Image of food supply chain

Rodents can threaten food safety at every stage of the food chain, from farm to transport, to storage, to food processing plants, warehouses, and even at the supermarket. Food loss and wastage occur throughout the food supply chain, literally from farm to fork.

Furthermore, food producers often decide not to use raw materials that fail to meet quality standards. In cases where rodent-induced contamination is detected in raw material, large quantities of finished food products may also have to be discarded. With the global population projected to reach 10 billion by 2050, this will require a 56 percent increase in food production from 2010 levels, and food loss and wastages will prevent us from  reaching this goal.

What Sort Of Damage Do Rodents Cause To The Food Supply Chain?

The World Resources Institute estimates there will be 10 billion people on earth by 2050, leaving a potential 56% food gap. That is a huge amount! With the need for ever more food production and global trade, and the growing demand for storage of produce and production of food, rodents are becoming an even more prevalent and costly threat, and efforts must be taken to curb the pest problem right across the food supply chain

Damage Caused By Rodents to Farm Crop

Image of a farm

Let’s start off by looking at the first stage in the food chain - the Farm. Some of the most destructive rodent pests in and around the farm facilities include the Norway Rat, the roof rat, and the house mouse. In addition to carrying over 35 diseases and viruses, they consume and contaminate the feed, gnaw on structural, mechanical, and electrical components, and weaken concrete slabs and walkways with their burrowing activities.

Rodents contaminate not only when they consume food but also through fecal droppings and shed hair. Moreover, for every rodent seen during the day in barns and poultry houses, there are likely 20 to 50 that are unseen. You can only imagine the collective havoc they can cause round the clock! So, you need to keep an eye out for the slightest signs of rodent activity because once they are inside, it may already be too late.

Damage Caused By rodents to the food processing plant


The second stage of the food supply chain involves Food Processing Facilities. We often think of rodents as nocturnal creatures that slip in and out of holes in the ground in search of food and water. This is often not the case, as rodents are not simply pests of the ground. Your food processing facilities’ safety and reputation may be affected as rodents can enter and infest buildings from above and below.

Image of  hospitalized individual

Not only do rodents cause diseases like Hepatitis E and Leptospirosis among factory workers, but they also contaminate food products and cause damage to machinery, leading to production downtime. In turn, this can harm the facility's reputation, cause temporary or permanent shutdown and loss of productivity, and strain financial resources.

The repercussions for a business may be severe. For example, the 2009 Salmonella outbreak at a PCA (Peanut Corporation of America) facility, although not exclusively attributed to rodents, led the facility to shut down permanently and resulted in jail time for its executives!

A particularly notorious pest in food processing facilities is the roof rat. Because these rats move around high up, they often go unnoticed and are very tricky to control. The amount of damage done by one roof rat can shock you-jJust one rat can cause thousands of dollars in product and structural damage.

And, because food processing facilities receive and send shipments out daily, it’s easy for rats to slip into transportation vehicles, packaged goods etc. They can chew right through packaged food products with their powerful teeth, thus contaminating food inside and outside the facility. Meat processing plants can also face risks from diseases like trichinosis, which can be contracted by those who eat undercooked meat from animals that feed on rats.

Damage caused by rodent to the storage unit

image of a ware house

Food products next pass to Warehousing facilities. Let us picture what a food warehouse would look like. They are structures typically spanning tens of thousands of square feet of storage space with ceilings 20-25 feet high and storage racks that climb to 15 or more feet above the floor. They store items on pallets and have one or more large doors. And these warehouse facilities tend to be built in industrial complexes that may be bordered by fields, rivers, wooded areas, or creeks.

As a result, you can be sure that there would be rodents in the environment surrounding the facilities. And here is the interesting fact, research shows that if there are 100 mice in a warehouse and 96 are captured or killed, the remaining four will persist and eventually rebound. So, persistence is an issue that needs to be addressed when it comes to rodent control.

Rats love grains, but when there isn’t enough supply of grains, they start eating almost anything. To get access to food, they gnaw everything, including exposing wires which can be a serious fire hazard. They can also scamper around shipments and get into packing, in turn contaminating the contents by nibbling, droppings, and hair, in turn damaging the company’s reputation.

Rodents lead to disruption, delay, and reduced productivity among workers, as employees often drop everything else to address this urgent problem or can fall sick due to rodent-transmitted illnesses.

The problem is even more persistent during winter as, like humans, rodents are looking for shelter from the cold. And voila, what better place than a big, warm warehouse to offer so much sustenance and shelter!

Effect of rodents on the grocery store

Finally, food products and produce make it to your neighborhood grocery store. A grocery store is where the consumer will come directly in contact with the product he or she intends to buy. Needless to say, they will also get to see the conditions in which their products are stored.

Image of the fruit section of a grocery store


With most consumers having access to digital devices and social media accounts, one bad incident resulting from the presence of rodents in a store can flare up, becoming a public relations disaster, damaging the store’s reputation in an instant. A Tik Tok video of a rodent eating out of a meat showcase in Manhattan (hard to believe, we know!) and rodents at the meat section of a Kroger’s store went viral recently and gained so much attention from the public and the media. Incidents like this damage a store’s reputation and, in the worst-case scenarios, may lead to temporary or permanent shutdown by the health department and serious financial loss.

Rodents cause cross-contamination in the grocery store by defecating and urinating, thereby spreading diseases. They lower employees' productivity, cause damage to the products, and cause costly structural damages.

But even with all the preventive measures in place, rodents can still manage to find a way into the stores. 

Effective Rodent Control Strategies

Rodent Exclusion

Before we get into the details, Rodent Exclusion/proofing is all about keeping them from entering in the first place.

Image showing proper sanitation against rodents
  1. Rodent Proofing: The first step toward rodent exclusion at each stage of the food supply chain is to rodent-proof the structures used for food production, storage, and sales. This can get tricky since rats and mice can squeeze through holes just large enough to pass their heads through, as small as ¼ of an inch across for mice and ½ inch for rats. To make matters tricky, these rodents are extremely tenacious, as they can climb through pipes, jump vertically up to three feet and horizontally up to four feet, and climb wires, cables, vines, and trees to enter a building. Rodent proofing must block all entry points, and openings must be sealed with mortar, concrete, sheet metal, and hardware cloth around augers, pipes, and wires where they enter structures.
  2. Proper sanitation: The second step is to practice good sanitation methods. The food, water, and nesting material must be identified and eliminated. Some of the recommendations include cleaning up debris and trash, storing feed in metal cans with tight-fitting lids, and drying up the water sources like dripping faucets or leaking pipes.
  3. Avoiding Vegetation: Another good practice is to avoid planting bushes and shrubbery next to facilities such as warehouses and processing plants and not having plants such as evergreen and juniper bushes or vegetation that produces fruits or nuts to eliminate a food source for rodents. It is also important to include outside grounds, production equipment, and transfer systems on the exterior of buildings in the facility’s Master Cleaning Schedule.

At warehouses, food storage has to be split up into sections so that if one sector is infested, you need not throw away everything. Sanitizing the spaces well by removing water sources, cleaning up spillage immediately, having a no food policy inside the warehouse, clearing up rubbish and old pallets, and ensuring that food that comes in first goes out first also helps.

Use of Rodent Traps

One common control method for rodents are the traditional mouse traps. There are many versions of mouse traps available in the market today. Did you know that rodents have a small home range, with rats traveling no more than 100 feet and mice less than 30 feet from their nesting site? So, based on circumstances, trapping can be an effective, quick, and economical method of control for the farmers in particular. In places like grocery stores, rodent traps may be placed around and inside the perimeter of the building to monitor rodent infestation.

Common snap traps, glue boards, and live traps supplement baiting programs or replace them in situations where baits may pose a hazard. But no matter how careful you are with rodent traps, there are always challenges!

There is the possibility that children or animals can come into contact with it. Mice caught in glue traps cause another problem: getting rid of the mice. You might need to either kill the mice or take them somewhere far away from your home, business, or farm so that they don’t immediately return.

Using snap traps outdoors can also harm wildlife like birds, for example. And since rodents are cautious of new objects, traps must be kept in place for at least a week to be effective. As you can imagine, trapping rodents is time-consuming and challenging if the need to control their numbers is time sensitive.

Use of Rodenticides

There are, of course, rodenticides or poison baits on the market formulated as bar baits, pellets, concentrates, or tracking powders. They should only be used per package directions and kept in safe, secure storage in areas where they risk contaminating food directly.  Traps are the main form of pest control inside an establishment, especially in food processing areas, but in places where bait is required, they should be placed inside a bait station. The baits should be in a  block form as it prevents the pests from transporting the bait and contaminating food.

The rodenticide baits registered for use by professional applicators to control rodents in or near (within 100 feet of) buildings and other structures or for use in and near agricultural buildings contain anticoagulant compounds that interfere with blood clotting and cause death from bleeding. Death usually occurs four days to two weeks after rodents begin to feed on the bait.

There are the first generation anticoagulants and the second generation anticoagulants (SGARs). Second-generation anticoagulants are more likely than first-generation anticoagulants to be able to kill after a single night's feeding, making them more lethal. But since they remain in animal tissues longer, they also pose a much greater risk to non-target species.

The Downside of Chemical Control of Rodent

danger sign for chemical control of rodent


Chemical rodent control poses a high risk for accidental poisoning of people and animals. They are toxins used to kill mammals so humans can suffer similar harmful effects from this poison. For example, US National Poison Control Centers received over 73,000 calls for accidental human exposure to rat poison in 2015 alone.

As mentioned, It is not only humans who get exposed. At poultry farms, for example, poultry gain access to the poison baits. The potent second-generation rodenticides, such as brodifacoum, are especially dangerous to birds. The main animal species to be affected are the birds of prey, with many press reports showing how severe the effects are. So, in the end, we are killing our friends like hawks and other raptors, which are natural predators of the rodents!

It is recommended that efforts be made to track down poisoned rodents so that remains can be disposed of safely to avoid accidentally poisoning wildlife and pets. But this is not always possible, given that poisoned rodents may die far away from the location of the poison bait stations and in inaccessible locations such as burrows or wall crevices.

Though you cannot usually find SGARs on shelves in retail stores anymore, they are still allowed to be deployed by licensed pest control professionals in "tamper-resistant" bait stations to reduce child exposure. But studies determining whether the bait stations reduce incidents of child poisonings due to SGARs seem to be limited. On the other hand, over 25,000 cases have been recorded by the EPA between 1999 and 2003 of children under six being exposed to poison from rodenticides. About 15,000 calls come into Poison Control Centers yearly of children accidentally consuming rodenticides.

Image of disease causing  bacteria


Additionally, studies show that the rats or mice that consume SGARs are more susceptible to contracting some diseases, like leptospirosis and E. coli which they can transmit to humans.

Needless to say, extreme care should be taken to ensure that the poison baits are placed in areas where they are inaccessible to children, pets, livestock, and wildlife. The bait boxes also should be tamper-proof as the box should not be opened and the contents taken out. If rodenticides are placed in areas prone to flooding, the poison could contaminate the fields, packing areas, irrigation channels, and drinking sources for farm animals.

Even though there are requirements that rodenticides should be stored and placed in a way that prevents poison contamination to food sources, there is much effort needed to take adequate precautions to prevent this from happening. A lot of expertise is needed to determine the type of bait to be used, where it should be placed, and the frequency, documentation, periodic monitoring, trained staff, and maps of all the bait stations should be maintained. Beyond this, there are also chances that rodents that consume a rodenticide may die in a wall void of a warehouse or food processing plant, thus creating an odor and attracting secondary pests, or outdoors thus posing the risk of residual poisoning to non-target animals.

Finally, there are an increasing number of bans on rodenticides. There are already numerous efforts to ban the use of Rodenticides in North America. For example, the state of California prohibited many uses of second-generation anticoagulant rodenticides (SGARs) from Jan 1 2021. Likewise, certain types of rodenticides such as fumigants are typically prohibited for use in grocery stores.

Eco-friendly Rodent Control; A Better Way to Prevent Rodent Damage

An eco-friendly environment

With so many ill effects of using chemicals and the risk of contamination, you will certainly be wondering if there are safe and more humane alternatives to these chemicals with regard to preventing or mitigating pest issues. In fact, EcoBloc offers just that! More humane than traps and safer than poisons, and environmentally sustainable, our product minimizes human contact with disease-bearing rodents.

EcoBloc works like an invisible fence around the facility and works to repel rodents by emitting high-frequency ultrasonic waves that create a hostile environment for rodents. EcoBloc uses a proprietary algorithm to change the sounds so that the rodents do not get habituated to the sound.

Best used as a part of an Integrated Pest Management program, EcoBloc works to keep these pesky little intruders at bay! In cases where there is no other food source readily available, you can direct Ecobloc Ultrasonic sound to drive rodents to areas where you can place a trap or bait. If you still wonder what IPM means, let’s get to it next!

Integrated Pest Management (IPM)

Integrated Pest Management is an effective and environmentally-sensitive approach to pest management that relies on a combination of common-sense practices. To be concise, IPM is not a single pest control method but a series of pest management evaluations, decisions, and controls. Together, they are designed to minimize pest damage by the most economical means possible and with the least possible hazard to people, property, and the environment. 

Summarizing IPM, it follows a four-tiered approach

  • Set action threshold: This is setting the point at which control needs to be taken, and in case you are wondering, sighting a single pest does not always mean control is needed. The threshold depends on the situation at hand, like the type of facility and how sensitive its operation is to the presence of pests.
  • Monitor and identify pests: This is done to prevent the unnecessary use of pesticides or the wrong kind of pesticides. This stage begins with identifying the pest and whether control measures are needed or not for the pest in question.
  • Prevention: As the first line of pest control, this step focuses on managing the crop, lawn, or indoor space to prevent pests from becoming a threat. This could include measures like preventing the pests' entry into the space in question and maintaining general cleanliness in the space/facility.
  • Control: After the initial two steps have been decided and the third step is no longer effective or available, IPM programs then evaluate the proper control method for effectiveness or risk. For control, the less risky and more effective options are chosen first, like pheromones to disrupt pest mating or mechanical control like trapping. Another strategy is biological control through the introduction of predators. If these measures are not working, additional pest control methods are employed, like the targeted use of pesticides.

By following a logical sequence of actions, IPM can create an optimal solution to prevent/minimize damage due to various pests. By taking a series of steps before initiating rodent control, IPM ensures that every effort is made to avoid using hazardous and environmentally-damaging rodenticides.

Even when rodenticides may have to be used, this is done in the most targeted way possible, both in terms of selecting the most appropriate agent for the type of pest being targeted and choosing the safest and most efficient way of deploying the rodenticide.

In conclusion, the global food supply chain is a complex web of facilities and processes critical in bringing various food products to our tables from sources worldwide. Rodents cause billions of dollars of direct and indirect damage to the food supply chain resulting in the wastage of food that could have fed tens of millions of people.

Minimizing or preventing rodent damage in the food supply chain is a constant battle at every location in the chain, from the farm to the grocery store. The first line of defense is to exclude rodents from the facilities by eliminating means of access. Introducing active exclusion control measures, like EcoBloc, is an effective strategy to keep rodents out.

Where exclusion fails, rodent control measures have to be adopted. While the first option that springs to your mind is using traps and chemical rodent control, both have drawbacks. Chemical rodenticides can poison humans and non-targeted animals, posing a serious health hazard and environmental damage.

The best solution, as we have seen, is to adopt an Integrated Pest Management strategy that not only minimizes the downside of rodenticide use but also provides the most effective solution by tailoring the response to each type of pest/rodent present and combining pest prevention strategies such as rodent exclusion with rodent control measures. By identifying and deploying the most effective methods based on the scenario, we can minimize rodent damage without wasting valuable resources and avoiding collateral damage.

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