The Rise and Fall of German Cockroaches

Features - Pest Control

Employees Bring Resurgence

April 9, 2013

Cockroaches are a common pest in any food facility, with German cockroaches being both the most common and the most difficult to control. That said, there are differing viewpoints as to whether cockroaches are more or less common in food processing facilities today than they were in the past:

“We’ve found that the German cockroach is making some comeback in food processing plants. I think they are coming back big time.” Dan Collins, president of Collins Pest Management.

“I think cockroaches used to be a much bigger issue in food facilities, but as awareness of food safety has increased and the evolution of third-party audits has increased, it has forced the hand of the food processor to have better processes in place.” Hank Hirsch, president, RK Environmental Services.

That, however, is the extent of their differences. Whether considering that there has been a rise or fall in cockroach infestation, Collins and Hirsch agree that the vast majority German cockroaches that are found in food plants can be traced back to employees and their belongings.

This may be a surprise to those who have continually focused pest management efforts on the dock and incoming goods. While supplies and ingredient deliveries are a risk and are the secondary cause of German cockroach infestations, the first line of defense needs to be at employee locker rooms, break rooms, and any other areas in which belongings are brought or stored.

Collins and Hirsch were in full agreement on that point:

“We are finding that 95% of German cockroaches are coming in on employees and their personal belongings, from their homes.” Collins

“The #1 way that German cockroaches get introduced is through the locker rooms because employees are bringing the cockroaches from their homes.” Hirsch

Those who live in multi-family housing are particularly susceptible to cockroach infestations in the home, as the cockroaches move easily from apartment to apartment or condo to condo through the walls.

Prevention. Pests can be divided into two groups: those that pose risk to public health and/or property and those that are simply a nuisance, said Missy Henriksen, vice president of public affairs for NPMA. And with the health risks they cause, cockroaches are definitely in the first group, particularly in relation to foods.

Cockroaches can transmit 32 types of bacteria, Henriksen said, including Salmonella and E. coli. Whatever they crawl across and get on their bodies, they can then transmit to foods and food-contact surfaces upon which they crawl.

Because so many German cockroach infestations can be directly attributed to employees, it is important to have programs in place to prevent the spread of any cockroaches that are brought in and minimize potential risk to the food products or areas. Such a program will able provide prevention of other employee-originating pest problems, such as bed bugs. To have a comprehensive, effective program:

  • Companies should use a uniform service by which employees put on uniforms in the building, leave their street clothes in lockers, and the service launders the uniforms. Uniforms should never be worn or taken home by employees.
  • Employee clothing and belongings should always be segregated from other areas, so that they are never taken from the locker room, break room, or other designated employee area. Personal clothing should not be allowed in food areas, e.g., if an employee wears a jacket into the area in the morning, then decides to take it off, he or she may end up setting it on a processing line—which is a haven for pests such as cockroaches.
  • Provide a special storage area for personal coolers, limiting the size that may be brought in, and allowing no open containers.
  • Locker rooms and break rooms should have regularly scheduled cleaning and inspection in which lockers are cleaned and opened for inspection, break room items cleaned and inspected, etc.
  • A strong, proactive monitoring program should also be in place throughout these areas, e.g., cockroach monitors can be placed in locker rooms, restrooms, beneath vending machines, sinks, etc.
  • Implement a training program to ensure that employees understand not only what they need to be doing, but why. “Employee training and awareness is key,” Hirsch said.

If German cockroaches are found in other parts of the food plant, it is likely that, as you work your way back to the source, you will find that the infestation boiled over from employee areas, and is caused by not having the above components in place.

However, other areas should not be neglected, rather all areas should be inspected for and cleared of cockroach attractants, such as leaky pipes in the restroom, unsanitary trash or recycling bins and areas, and general clutter and debris, Henriksen said. To prevent those cockroaches that do come in from the outside, external areas should not be neglected, and grass and landscape areas should be well maintained.

Incoming Goods. While the vast majority of German cockroach infestations are introduced by employees, the secondary cause is that of incoming goods, both Collins and Hirsch noted, with Hirsch stating, “The risk is still very real that supplies could be introducing cockroaches—whether it is packaging material or ingredients. That’s why a good food safety program includes inbound inspections.”

Cockroaches and other pests can even come in with goods from other facilities of the same company, Collins said, adding, “You should have a strong gatekeeper program in place with a trained person who checks anything that gets brought in.”

And once inside, the cockroaches will quickly scurry to warm, sheltered harborages. Cockroaches live in voids, so to find and eliminate them, Collins said, “You need to become a ‘voidologist.’ You start looking for voids anywhere you can’t get into or see. ... That’s where they are going to be.”

Warehouse areas into which the cockroaches are brought can provide all kinds of attractants, food, water, and shelter for cockroaches that do come in. To combat this, Henriksen said, facilities should always practice first in/first out rotation of goods to ensure freshness and get rid of food temptations as soon as possible. Also, to ensure the ability to inspect and clean warehouse areas, all areas should have at least a 12- to 18-inch walkway around walls.

One example outside the warehouse area that Collins gave is that of a bakery where the cockroaches were living in electrical panels. Because these were directly adjacent to the food processing area, the cockroaches would hide out in the warm void behind the panel, crawl down the cord to feed, then climb back up into their warm harborage. Collins has seen cockroaches infest in very cold processing rooms in similar ways, even living within the mixing equipment where the motor kept the area warm.

German cockroaches anywhere in a food plant are a problem, but when they are living this close to the food that is being processed, the risk can be significant. “Anything that can contaminate or adulterate product is a risk to product integrity and human health,” Hirsch said. Cockroaches will walk across garbage then across your food lines—carrying disease bacteria on their bodies that contaminate the lines, then your food.

Cockroach control.
In the past, German cockroaches were controlled through fogging and space treatments, Collins said, which actually only pushes the cockroaches further back into the voids. “There used to be scheduled spraying in the food environment, but our industry has moved away from that approach.” Now cockroach control is inspection based, with inspection and monitoring as a priority, then precise, targeted application of gel baits where approved and applicable. “When roaches are in a processing environment, it has to be approached in a systematic way,” he said.

Today’s targeted programs minimize risk to product and people’s health, as well as reducing the invasiveness of the food plant processes and the need to shut down the lines, then clean the food surfaces afterward, Hirsch said.

American Cockroaches. Although they are generally less of an issue than German cockroaches, American cockroaches can be an issue in food plants. Because they live in deep, dark areas, tunnels and roof vents, “American cockroaches are really overlooked in food processing plants,” Collins said. And because they enter from utility systems, such as steam tunnels and sewer lines, then spread through a facility, the means of control are completely different.

American Cockroaches are often overlooked in food processing plants. Clemson University - USDA Cooperative Extension Slide Series,

For American cockroach control, Collins said, it’s a matter of finding the entry points and excluding them.

“American cockroaches are more of an environmental issue,” Hirsch added. They are not being brought from homes and are not as likely to be brought in on supplies without being observed. Because they do live in sewer systems, entering through floor drains and cracks in slabs and foundation, you can never really eliminate the source. Rather exclusion techniques, such as tight screening of floor drains, sealing cracks and crevices, and regular inspection of all potential areas, need to be incorporated to keep them from coming in.

Five steps to success. Cockroach control is a five-step process built on a partnership between the food facility and the pest control company, Collins said. The five steps are:

  1. Identify the pest. Correct identification of the pest and species is critical for control.
  2. Take system-based and corrective action. The source of the infestation and severity of population should be established to ensure proper action is taken. For example, if a German cockroach is found on a monitor, was the source an employee’s belongings or incoming goods? How far has the infestation spread?
  3. Eliminate conducive conditions. Conditions that are conducive or potentially conducive to ongoing threat from this pest need to be determined. For example, what is the cleanliness of locker rooms? Are employee belongings being segregated? Are steps being taken to stop cockroaches that may come in? “That which can be foreseen can be prevented,” Collins said
  4. Treat. What is the best pest management practice? Can sanitation and cleaning or exclusion and sealing solve the problem? In a food plant, unless there is a large, widespread cockroach issue, it is usually a cleaning or cultural issue, he said.
  5. Follow up. If after this, cockroaches are still or again found, start back at #1: Conduct a supplementary inspection, determine corrective action, eliminate conducive conditions, treat as needed, then follow up again.

Too often, service providers and/or plant management want to go directly from step #1 to #5, Collins said. But success is based on following all five steps with partnering and teamwork between the service provider and the plant. “It’s a partnership,” he said. “When I walk into a facility, the Collins shirt comes off and the facility’s shirt goes on.” It’s all about brand protection.


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