[Cover Story] Bar Flies

How to guarantee it will be the "last call" for fruit flies and other small flies in bars and food establishments.

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June 22, 2007

The American Heritage Dictionary defines a bar fly as “one who frequents drinking establishments.” Maybe our most famous bar flies are Cliff Clavin and Norm Peterson of the popular sitcom “Cheers,” the bar where everybody knows your name. When it comes to fruit flies, which are common in bars, however, the names they are called are not their proper name, at least not by patrons of a bar. “Gnats” and “flies” might be common terms used for small flies, but likely after a period of bothersome activity, small flies take on more profane personifications.

From the fruit fly’s perspective, it’s only doing what it is supposed to do. A fly’s obligation is survival and propagation — nothing more. When adult flies frequent a fruity drink or a plate of food, they are doing nothing more than seeking sustenance. Their persistence at trying to reach our food that annoys us so, is nothing more than their natural urge to survive. It is the restaurant or bar and their sanitation practices that create the environment for fruit flies to establish themselves. Once they have “planted their flag,” so to speak, in a mass of wet organic material, the flies will remain and proliferate until their sources for sustenance and survival are removed.

The fruit flies comprise a large and varied genus of species, only a relative dozen or two species of which are found in food-handling establishments. These are not the only bothersome small flies found in such facilities, however. Phorid flies, moth flies and fungus gnats also are common. Fruit and phorid flies are the ones most concern in bars and restaurants and, fortunately, the basic steps for resolving an infestation for either are relatively similar. This article will discuss these groups of flies that are prevalent residents of bars and food establishments and outline guidelines for successfully resolving and preventing infestations.

BAR FLY ESTABLISHMENT. Spend a few hours in any food-handling establishment — restaurant or bar — and you’ll find a lot going on. Precious little time appears to be spent on cleaning up. Also, every action taken to prepare food and serve customers seems to deposit something onto floors and into cracks that could support flies and other pests. Most facilities are not designed with easy cleaning in mind, especially given the tight spaces available inside.

If it were just the bits of food, grease and debris that find their way into the corners and cracks at floor level, issues with flies might not be so prevalent. It is the sheer volume of water, however, in these environments that leads to perfect conditions for thriving populations of fruit and phorid flies. Many restaurants conduct their cleaning via power washing with hoses — it’s faster and more convenient. Water takes the path of least resistance, however, so this method forces water into all available cracks and crevices, usually taking grease and food debris with it. Hundreds of possible breeding sites are thus created, allowing small flies to get their start.

Most customers feel their fly issues are only associated with the drains. Phorid and moth flies are common inhabitants of drain systems, but fruit flies are rarely so, except possibly the dark-eyed fruit fly, which breeds in environments more akin to those of phorid flies rather than that of their bright red-eyed cousins. Red-eyed fruit flies feed on various yeasts that develop on organic matter that is relatively new or in mild decay. Phorid, moth, and dark-eyed fruit flies can breed in new materials as well as organics in an advanced state of decay. The common thread through all of this is the fact the organic matter must remain constantly moist. As discussed earlier, in a restaurant or bar, moisture is never in short supply.

Fruit flies can develop from egg to adult in as little as seven days. Populations can go from zero to unbearable in a few weeks. It doesn’t take but a few flies to annoy a restaurant manager when his customers are being annoyed.

By the time flies are well established, eliminating them can be quite difficult because most of the solution resides with the facility itself. As we all so painfully know, if the restaurant or bar manager is unwilling to address the sanitation issues causing the problem, nothing a pest professional can do will satisfy that customer. All the treatments in the world will not resolve the fly problem.

BAR FLY PREVENTION. If a pest professional was ever lucky enough to be consulted by a restaurant customer in the planning stages of building a facility, he might have some helpful recommendations. A facility should be designed not only with the efficient preparation and serving of food in mind but also with efficient daily cleaning. Having most equipment on wheels and flexible pipes and hoses would be excellent as the equipment can be pulled away from the wall and easily cleaned behind. Such facilities like this do exist.

Water management also is important. In areas of excessive moisture, like a dishwashing room, the wall board behind the walls needs to be of the most water-resistant type. It is also helpful if ceramic tiles can extend at least halfway up the walls — an extension of the floor itself. The tiles along the base of the wall should be coved so no grout joint exists at the base of the floor/wall juncture. The floor also should be poured so that it gently slopes back away from the wall toward the center of the room. Water forced when cleaning toward the wall then flows back toward the center where it can be mopped up or squeegeed into drains.

Of course, this is the real world and the varied construction practices and ages of buildings are more favorable toward the production of flies rather than prevention of such pests. In this real world, rigid adherence to a master cleaning schedule is paramount to effective minimization or prevention of small flies. Again, diligent cleaning efforts are hampered by the reality of time availability and labor costs. It often takes the unfortunate instance of health department “intervention” to prompt a food establishment to invest in micro-level cleaning efforts necessary to control flies.

At the very least, if a facility would clean the drains effectively on a weekly basis, some fly issues could be minimized. Drain cleaning in restaurants, however, often involves using hot water and bleach, which does little to actually clean a drain.

So where does this leave us? Preventive efforts in design or cleaning just do not often occur, leaving no shortage of flies with the ideal habitats to thrive.

BACTERIA VS. BAR FLIES. Around 10 to 12 years ago, several companies began introducing bacterial products to help deal with grease and other organic matter in restaurants (and grease traps). Through the digestion of grease and organic matter, bacteria have the side benefit of reducing fly populations by removing available food resources. A number of companies now offer bacterial products. Those mentioned in this article are the ones with which I am personally most familiar. It is up to you to look at all products and to talk to the manufacturers and distributors to determine which products may work best for you.

Bacterial products over the years have proven their ability to help manage small fly infestations. Implementation of such products is recommended in any restaurant or bar environment, even when flies are not evident. These products offer pest professionals the opportunity to be proactive in addressing fruit, phorid and moth flies. It does, sometimes, take a concerted sales effort to convince clients to invest in purchasing bacterial products and then to use them correctly.

Most failures of bacterial products occur because customers, or especially their employees, do not use the products effectively. The most common problem is adding the bacteria to mop water that also contains other cleaning products. Or cleaning products are used in mop water where bacterial products are separately being applied to drains. Bleach also is often poured into drains after bacteria have been applied. Such use of cleaning products kill the bacteria thus negating their ability to do what they were designed for — eating grease and food debris. Customers need to be convinced to remove their old cleaning products and to give bacterial products a chance to work. It is advantageous to schedule training with a facility’s employees to explain how to use such products effectively. Also, depending on the situation, it may take several weeks to see positive results in fly populations with bacterial products.Make sure each customer is advised of what to expect.

Drain Products. DrainGel (BioSys, www.biosysinc.com) and Vector Bio 5 (Whitmire Micro-Gen, www.wmmg.com) are two of the many drain products that are available. They are applied at different rates and frequency depending on the product’s label. Often, bacterial drain products also may be mixed in water and applied in locations other than drains.

Mop Products. BioSys MRT 2000 is the mop product with which I am most familiar. A facility will use MRT 2000 in place of any other cleaning product added to the mop water. The beauty of mop products is that wherever the mop pushes water, the bacteria follow. The bacteria then wind up in the places that water, grease, and organics have been accumulating. Given time, the bacteria will consume these materials, thus depriving any fly larvae of food, resulting in their demise.

The other benefit of mop products is that they continually add bacteria into the places where flies might be or are breeding. More bacteria create faster results. The only “negative” that I have seen with mop products is that customers may complain that their floors are no longer shiny. Why were the floors shiny in the first place? Why, the grease, of course. The “shine” also made floors slippery so removing any layers of grease buildup have a safety benefit as well.

Hose-End Products. BioSys also makes a product that is applied from a hose for those facilities that hose down their floors. A hose-end device is needed for applying this product. The same benefits seen for mop products apply to hose-end bacterial products. Bacteria are pushed into all places the water travels. Some facilities wash down their floors twice a day. Regular applications of bacteria help speed results.

Foaming Products. Currently, one of the popular bacterial products on the market is InVade BioFoam (Rockwell Labs, www.rockwelllabs.com). BioFoam is applied from a foam sprayer, such as the Foamer Simpson (Rockwell Labs), to drains and sites where fruit flies might be breeding. This product is applied by a pest professional as both an initial treatment for flies and monthly as a follow-up to minimize fly activity. BioSys is introducing a similar product to the marketplace soon.

SUBSLAB INFESTATIONS. If the fly problem persists despite all efforts to discover the breeding sites, and cleaning/bacterial products are not working, it is likely that a subslab infestation may be in place. These result from drain line breaks that deposit wet organic matter into the soil, and huge fly populations can result in some cases.

If a subslab infestation is suspected, a plumber can be called in by the customer to check for a drain break. If one is found and repaired, it is imperative that all the wet, contaminated soil be removed underneath and replaced with clean dry soil. If the drain line simply is repaired and the wet soil remains, the fly problem will continue.

SUMMARY. Small fly species are annoying and persistent in food establishments. Without the restaurant or bar management’s acceptance of their role and commitment to cleaning operations and repairs, fruit, phorid, and moth fly infestations are typically impossible to resolve. A pest management  professional needs to be involved in: 1) assisting in discovering the breeding sites; and 2) educating and selling the client on the importance of their cooperation. Treatments cannot solve a small fly problem nor can traps. If the breeding sites are not addressed, then the problem will persist. Bacterial products show much promise for long-term resolution of small fly issues, if they are properly utilized. Constant vigilance by the service professional is needed to help point out areas of concern before they become a problem. Staying ahead of the fly’s ability to populate quickly is the best strategy.

The author is a board certified entomologist and professional sanitarian. He is director, technical services, Terminix International, Memphis, Tenn.

Attracting And Catching Flies With Traps

A number of fly traps are now available that will attract and catch fruit flies. Traps can be useful in pulling numbers of flies out of the environment, enough so that the restaurant’s or bar’s customers are less likely to note them. These traps will not solve a fly infestation — they are useful population monitors until the breeding sources can be found and corrected.

Traps also can be used to help pinpoint the source of an infestation. A number of traps can be placed through an area in a grid-like manner. The traps that catch the largest numbers of flies generally are closer to a breeding site. Traps should be placed closer to the ground rather than higher.

A few of the traps available to the pest control industry include Vector 960 (Whitmire Micro-Gen), InVite Fruit Fly Trap (Rockwell Labs), and the Smart-Way Fruit Fly Trap (Insects Limited). All these traps catch various species of red-eyed fruit flies, but the InVite trap has shown the ability to also attract and capture the dark-eyed fruit fly and phorid flies.

Unlike “filth” flies, neither fruit flies nor phorid flies react strongly and positively to UV lights in insect light traps. At certain periods, however, adult flies may become attracted to ILTs as evidenced by the fact that one can find fruit and phorid flies in the glue boards of ILTs. Typically, it is the males that end up in the traps, but females end up there as well. Where large numbers of fruit and phorid flies are present, ILTs may capture large numbers of adults, yet have little impact in reducing the presence of flies. — Stoy Hedges

Finding The Breeding Spot

Maybe one of the most difficult tasks asked of pest professionals is an inspection to uncover where fruit or phorid flies are breeding in a restaurant or bar. Countless hours can be spent tracking down, one-at-a-time, the many sites where flies might have set up shop to determine if flies actually are breeding at a spot and not just visiting it.

The best spot to start is the drains, as they are easily accessible for inspection. Do you see any adult flies in or around the drain? If so, this does not mean that the drain is a breeding source — the flies may simply be investigating the drain. Organic matter in the drain and around and up under its lip should be scraped out and checked for larvae. The presence of fly larvae in any organic matter is a confirmed breeding site.

Since fruit and phorid flies can breed in tiny amounts of organic matter, the following is only a partial list of areas or sites to check as breeding sources in a restaurant or bar.

  • Bags or boxes of produce that are not refrigerated.
  • The bottom of trash containers, under the plastic bag.
  • Debris trapped in ANY crack at floor level.
  • Pieces of fruit or food under equipment or the bar.
  • Soft drink dispenser drains.
  • In voids of cabinets, above false ceilings and other areas where soft drink lines may run.
  • Underneath any item that sits on the floor for a long period. For example, moth fly and dark-eyed fruit fly larvae commonly are found in wet debris that collects under soap containers and other items sitting on the floor under the dishwasher.
  • Under rubber mats on the floor.
  • Any site where moisture is causing a visible degrading of the walls or floor tiles.
  • Any cardboard that appears to be constantly wet.
  • Recycling bins or receptacles.
  • On top of coolers, behind equipment or in false ceilings (facility employees have been known to throw partially eaten food in such areas).
  • Elevator pits.
  • Exterior Dumpsters and compactors, especially if these are close to the back door.

Remember, any organic material that stays constantly wet for an extended period is suspect. When one breeding source is confirmed, it is important to continue searching as more breeding sites are usually present.