Ants: A Tiny, Relentless Pest

Features - Features

A Q&A with industry experts on control and prevention.

April 19, 2018

By Lisa Lupo

There more than 12,000 species of ants around the world, of which nearly 1,000 are found in North America. Although only about 20 of these are considered to be pests, those 20 can be very relentless in food processing facilities. The challenges posed in their control and elimination are increased due to their small size and the vast differences that can exist in the biology, habits, and general characteristics among species.

In this article, QA takes a look at the threats ants can pose and the steps food processing plants can take for prevention through the eyes of three industry experts:

Bayer Environmental Science Pest Practices Senior Scientist John Paige, Nisus Director of Technical Services Reid Ipser, and Orkin Manager of Technical Services Chelle Hartzer.

1. Which ant species are most likely to be a threat to food processing facilities? Why?

Any species of ant that enters a food facility is a threat due to being a potential contamination issue. The species of ant infesting and threatening food plants is highly variable depending on geography and time of year. Thus, there really is no one answer to this question. For example, in the spring in the southern U.S., crazy ants are fairly common, but as it gets warmer, red imported fire ants become more of a threat.

The answer to “why?” almost always comes down to the basic biology and life cycle of each particular species.

Taking crazy ants as an example: These ants forage widely in the spring looking for protein food sources, so they may enter buildings then that they wouldn’t in the summer due to a shift in food preference. In the spring, protein is important to provide nutrition for the queens to produce and lay adequate numbers of eggs.

Once the worker ants have been produced and are foraging (in the summer), the most efficient food source for the colony becomes carbohydrates, such as that produced by sucking insects like aphids, scales, etc. and found naturally in nectar and honeydew of plants so crazy ants forage mostly on and around plants at that time.

Red imported fire ants, on the other hand, do not have an important food preference shift. They prefer oils and proteins year around and can forage in warmer temperatures.

The end result is that crazy ants tend to infest buildings in spring and early summer while red imported fire ants tend to appear later in the summer. Other species of concern are odorous house ants, which tend to forage inside structures, and super-colony ants, such as the Argentine, that will trail long distances for food sources.

2. What are the primary means of ant entry to food facilities?

Any opening, particularly on ground level is a potential entry point. Ants also may be brought in on pallets or on goods delivered into a facility, especially those packaged in cardboard.

Ants can find their way into a food facility or any industrial site very easily. Due to their small size and foraging behavior they are very difficult to seal out. Food plants often have doors that are open for deliveries and many cracks and crevices around windows, utility entrances to the building, etc.

Additionally, many food processing plants leave outdoor lights burning at night that attract large numbers of flying insects. When the flying insects die and fall to the ground, they provide an excellent food source for ants.

While ants can enter through numerous entry points, the top four locations through which they enter are cracks in doors and windows; cracks in flooring; conduit lines in walls via electrical outlets or old interior construction; and on or in deliveries.

3. What hazards do ants pose to a facility and/or its food?

Ants can get into processing equipment, or even into finished product, where their presence can lead to recalls. Additionally, because foods adulterated with ants and ant parts cannot be sold, they will need to be destroyed. This is not only costly and time consuming, it wreaks havoc on production schedules. Ants also can damage electrical lines and electrical transformers, and possibly decrease the structural integrity of internal structural components.

4. Where do ants generally present the greatest hazard in the facility?

Each facility is different, so there is no really good general answer to this question. The only way to tell the most vulnerable areas of a particular plant is to have a professional conduct a thorough inspection and write a good report detailing all of the potential pest hazards.

5. Are control methods the same for all ants?

No, control measures differ from species to species and even within the same species from spring to summer to fall. Many ant species prefer carbohydrates, some prefer oils, and others prefer protein food sources, so the choice of bait depends almost entirely on the species. Additionally, in some instances, the food preferences will shift during the year, so a bait that works well in the spring will be entirely ignored in the heat of the summer.

With the many different species of ants with different habitats and biological functions, each situation will call for different management methods. Thus, proper identification of the pest species is the most important aspect of the management program because of the varied behaviors and life cycles.

There are some Integrated Pest Management (IPM) steps that can be taken that are universal, such as proper sanitation, inspection of goods entering the plant, constant inspections for incipient infestations, and exclusion practices. Reducing and removing the food source that is attracting ants and sealing them out of a structure are preventive practices that are applicable to all species.

But for the most part, the most effective control measures include properly chosen and applied baits which are species and season specific.

6. Are there control methods the food plant can implement? Or is an outsourced pest control provider needed?

Both. With regards to a professional pest management company being necessary, the answer is emphatically, yes. The knowledge and experience necessary to be efficient in inspecting for, identifying, and treating for ants requires a huge amount of study and experience that most in-house employees don’t have and can’t get in normal working environments. For example, a pest management professional can identify the species, which will lead to where the ants might be living, what they might be feeding on, and how to best manage the issue.

But, not just any pest management company will be qualified to provide effective services for food plants — and the potential cost of an infestation that slips through a poorly trained pest management provider is potentially disastrous.

It is the food plant, though, that will need to implement practices such as sealing openings, addressing sanitation issues both inside and outside the facility, and training all staff in what to look for and how to report it.

Overall, it takes a partnership to create a strong pest management program.

7. What are the top proactive steps a food plant can take for prevention?

There are many IPM steps that plant managers can take to discourage ant infestations. Some of the top practices are:

  • Sanitation is always the top of the list. If the food source can be reduced or even eliminated, the ants will have nothing to feed on and won’t be attracted to the facility. This includes the outside as much as the inside.
  • Proper sanitation and inspections are key elements that should be employed even if pest management services are outsourced. No access to food or water = no pest ants.
  • Exclusion is an important proactive step that facilities can take to keep ants out. Any opening that connects the inside of the facility to the outside should be sealed. Pay special attention to anything on the ground level, especially the bottom of door seals, dock doors, and expansion joints. Ensure the foundation and construction of the building are up-to-date and sound.
  • Educate employees. Let all employees at the site know what to look for and, most importantly, how to report that information. Your pest management professional is likely there once a week or less, but there are hundreds of eyes around your site that can be used to identify issues when they first start. Your service provider then can follow up quickly and efficiently.
  • Plant managers should do due diligence and make sure the company they consider hiring has effective IPM experience, quality assurance and quality control procedures and personnel, and qualified entomologists on staff. The companies who employ quality inspections and procedures have the best chance of preventing outbreaks of ants and other insects and also taking care of the problems when, or if, they occur.
  • Inspect regularly to spot issues before they reach a serious level.
  • Limit food where employees eat to a single area and have that area cleaned every 24 hours.
  • Keep an eye on areas around dumpsters, outside employee areas, and parking lots.

8. What other recommendations would you have for ant control or prevention in a food plant?

Find and hire a good, qualified pest management company and work closely with them at every step. Identify a point person for the pest management technician to communicate with at every service date, so they can go over the results of the inspection and control measures that have been initiated. Remember, pest management professionals are dealing with insects and other arthropods that have been successfully inhabiting the earth for millions and millions of years and are as adaptable as any other living things.

Ants are small and often hard to see, but populations can quickly build up into large colonies that threaten facilities. So identifying issues when they are small will greatly increase the chances of preventing more serious issues. Tell your service provider when you see issues and work on instilling sanitation and exclusion practices to help prevent ants and many other pests. Allow the provider to see maintenance records so he or she can make proper recommendations. Heed their advice — don’t be stubborn. Pest management professionals are trained to inspect for conditions conducive to infestation, so when they report on such conditions, it is a good idea to correct the deficiencies.

To be at its best, the pest management program in food processing plants, and all food facilities, should always be a partnership between the customer and the service provider.

The author is Editor of QA magazine. She can be reached at