You’ve Got Options

by Katie Lee

How to keep cockroaches out of your restaurant.

By Klaus Reichardt

Here’s something restaurant managers and owners need to know about cockroaches: they’re smart and getting smarter. First, they are learning to detect when a chemical pesticide has been sprayed or applied. Second, it doesn’t matter too much to them even if it has.

In fact, some of the most common types of cockroaches, such as the German cockroach (Blattella germanica), have developed what are referred to as biological “buffers.” Even when a chemical pesticide has been applied full force, these buffers protect the insect from dying or possibly even getting sick.

To address this, pest control companies are turning to scientists to keep coming up with new formulas and chemicals that can break through these buffers. Sometimes it works, and sometimes it doesn’t. Some pest control experts even believe the cockroaches stay one step ahead of these new pesticides, virtually eliminating their effectiveness.

Restaurant owners/managers know that once cockroaches find their way into the property, this means it can be an ongoing battle to get rid of them. Other than immunity to pesticides, another fundamental problem is that they multiply very fast. An adult cockroach can live between 100 and 200 days, and during that time one female produces four to eight egg “capsules,” each containing 30 to 40 eggs. Ultimately three or four generations of insects are born each year.

Another problem is that they tend to like commercial kitchens. There are usually lots of dark, protected places to hide in the kitchen; food items aplenty even if they have to break through packaging; and plentiful moisture either from cooking or cleaning. And, as we shall discuss later, there is a mysterious but very ordinary way cockroaches find their way into a restaurant kitchen.


So, we have discussed the immunity issues. What some pest control companies are advising their foodservice clients to do is to take a multifaceted approach to cockroach control. Chemicals still have a place in the battle, but we must also remember we are using powerful poisons in a place that makes food for humans to eat.

We don’t want to abandon chemical control, but another option that cockroaches thus far have not become immune to — or have not yet figured out — is the installation of customized trips. This is part of an integrated pest management system which tries to reduce, and in some cases, eliminate, the need for chemical pesticides.

Cockroach traps placed in common cockroach nesting areas, as we mentioned earlier, baited with what we can call a cockroach “lure,” can be a safe yet effective solution in reducing a restaurant’s cockroach problem. Also, as the roaches are trapped, managers and pest control professionals have a better idea of exactly what type of cockroach infestation they are dealing with and what types of pesticides might be more useful.

While the German cockroach is the most common cockroach in the U.S., others we might encounter in commercial kitchens include oriental cockroaches, smoky-brown cockroaches, brown-banded cockroaches, and American cockroaches. Altogether, we estimate there are about 3,500 different types of cockroaches in the world and nearly 70 different kinds living in the U.S.

The traps also give us an idea of the size of the population. If many insects are caught every day, this can indicate a colossal population. The goal is to eventually check the traps and find no roaches in them.

The Mystery Cockroaches

If a cockroach infestation is ongoing even when we employ different kill and control methods, then we need to consider other possibilities, one of which may be right under your feet. Cockroaches like sewers. Sewers are less impacted by outdoor weather conditions, and they provide lots of food and moisture for the cockroach.

But cockroaches are travelers. What usually happens is they find their way into plumbing fixtures and drain pipes. This is why the infestation may be right under your feet. Often the insect marches up the drain — especially if it is dry — out the drain, and finds a home in your kitchen.

It is unlikely that the cockroaches will come up pipes that are cleaned daily or that receive a lot of moisture. This is because the “P,” “J,” or “U” piping under the drain stays filled with water, blocking their way into the kitchen.

But some sinks and floor drains — especially in storage areas that may only be swept occasionally and not mopped — stay dry and any moisture in the “P,” “J,” or “U” traps below the drain dries out. When this happens, we now have an open door for cockroaches to invade a restaurant, the kitchen as well as the front of the house.

So how do we address this?

The answer is to find ways to keep moisture in those pipes at all times. Here are some of the ways to do this:

  • At least once per month pour two cups of water into all floor and sink drains that are rarely used. There is no need to use chemicals, just water. In hot and dry climates, this may need to be performed weekly.
  • While it is not necessarily recommended, pouring a thin layer of cooking/mineral oil down drains will keep the water from evaporating. Do this every few weeks. But be aware that these oils can become rancid, causing odors and even clogging up the drain over time.
  • Some facilities install what is called a “trap primer.” These units are connected to a water supply that detects when trap water has evaporated and releases small amounts of water into the drain to refill the trap. Some also work with timers. While the units themselves are not that costly, it can be expensive to have one installed in an existing commercial kitchen.
  • Another option is to use a liquid primer. This is an odorless, biodegradable liquid. Relatively inexpensive, pouring a small amount after water has been poured down the drain can keep the trap underneath the drain filled for several months.

These steps can also prevent another mystery from occurring. Keeping the drains and traps filled with water also prevents an odor problem that stems from drains that dry out and eventually start releasing sewer odors into restrooms and other areas of a facility. Often when this happens, management has no idea where the smells are coming from. So, in a sense, we are hitting two nails with one hammer: keeping cockroaches and sewer odors out.


— A frequent speaker and author on water conservation issues, Klaus Reichardt is the founder and managing partner of Waterless Co. LLC in Vista, California. Reichardt founded the company in 1991 with the goal to establish a new market segment in the plumbing fixture industry with water conservation in mind. The company’s principal product, the Waterless No-Flush Urinal, works entirely without water.

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