[Vertebrate Pests] Restaurants and Rodents, part 2

In Part 1 of this topic (PCT May 2007), I discussed how restaurants are prone to rodent invasions due to their obvious association with food and food refuse, as well as the inherent operational practices such as deliveries, frequently opened doors and so forth.

Many of us witnessed how the recent events of “Rats Gone Wild” in New York and other cities clearly demonstrate that the public has “weighed in.” Rodents, even one, inside a restaurant are unacceptable. Thus, there is an essential need for both ongoing surveillance programs as well as for quality pest management services.

To achieve this, a high priority should be placed on preventing rodent infestations from occurring in the first place (e.g., individual rodents arriving with deliveries, entering beneath doors, etc.). Certainly, a priority on prevention should originate with the client. But because the average layperson does not understand pests and pest management, it really is the pest professional’s responsibility to inform and educate a restaurant manager as to what and how prevention can be achieved.

Consider for instance, the typical scenario of how a mouse infestation originates and develops in most food serving establishments. A mouse or two entering from the exterior, an attached structure, or arriving via a delivery can easily remain undetected for several weeks and sometimes longer. These new “residents” often forage and nest in the out-of-sight areas of the restaurant such as in ceiling voids, along the dark sill plates of the basement, behind and within the storage clutter, below low storage shelves, within the compressor void of the refrigerators and ice machines and similar areas. After a relatively short while, rodent families are born and reared in such out-of-sight zones.

It is precisely this cryptobiotic behavior of rodents, combined with the ideal rodent habitat most restaurants offer, that require employing programs that achieve two key goals: 1) maximizing the exclusion of rodents in the first place, and then, 2) using rodent management programs that alert quickly to the arrival of any new incoming rodents and maximize the chances of eliminating any new arrivals before they become established infestations.

Let’s examine a quality restaurant rodent pest management program.
 
RESTAURANT RODENT EXCLUSION. Although you would think the concept of pest exclusion is elementary and obvious to pest professionals and restaurant owners alike, it is still rare to find the restaurant that is structurally tight. All penetrations and all gaps of all sorts at ground level and ceiling level into a restaurant should be sealed. (Duh!) Remember, food molecules by the billions will leak out of any openings that are not sealed. And pests of all sorts are “designed” morphologically and behaviorally to trace food odor leaks back to their sources.

A restaurant’s delivery doors are especially prone to rodent entries from either the exterior perimeter areas, or from the deliveries themselves. (Also, consider how often the back delivery doors are left open by kitchen staff on their breaks, or in their desire to have fresh air.)

Many restaurant owners confuse pest proofing with weather stripping. But of course, these are not the same. Pest proofing doors should involve the use of heavy-duty pest brushes such as are offered by companies like the Sealeze Corporation (www.sealeze.com) or similar products of good quality.
I always remind restaurant managers to look at all their doors from the inside during the day. Any light seen beneath or around the door the size of 1/4 inch (6 mm) will permit mouse entry, while openings of 1/2 inch (12 mm) allow rats.
Similarly, all holes in walls and other structural elements must be sealed (not caulked) properly to deny rodents nesting and travel paths. It is common in restaurants to find gaps around pipes and utility conduits. Rodents climb these lines and access structural voids when these penetrations are not sealed. Stuffing steel wool or other metal meshes into the openings is not sufficient. Nor is the quick fix of spraying expanding foam into these openings.

CLUTTER CONTROL. Both rats and mice take advantage of all the box and equipment clutter so prevalent in restaurants for their indoor harborages. Due to the typical space constraints of most restaurants, many back rooms and basements become cluttered. Boxes of all sorts usually are placed on the floor and against the wall. This practice is perfect for creating rodent runways and box-nests for the rodents.

Ideally, back rooms and basements should be kept as clutter-free as possible (if only!). Still, all items should be stored off of the floor by a minimum of 12 inches and preferably 16 inches. The space is necessary to allow cleaning staff access with brooms and mops.

Storage shelves should never be made of plywood sheathing and two-by-four studs because these are positioned too close to the floor, essentially creating rodent/cockroach caves that are ideal for nesting and hiding. The appropriate storage racks for food serving establishments are heavy-duty stainless steel, gravity feed/height-adjustable shelf construction.

Similar to the importance of not creating rodent “caves” on the floor, nor should rodent caves be created over our heads. Boxes/supplies should never be stored for prolonged periods on top of cooler boxes, freezers or in any other out-of-sight ceiling zones. In general, for the benefit of food safety, nothing should be stored in any area where the stored items are prone to being out of sight and out of mind. Nevertheless, every servicing pest professional should always inspect in such areas during each visit.
 
REFUSE MANAGEMENT. By far, food refuse is one of the most important contributing factors for bringing rats and mice to a restaurant’s premises, and then allowing them to proliferate on, inside or near the premises. Among the majority of restaurants, refuse zones are often kept only marginally clean. The truth is rats and mice thrive on these “marginally clean” refuse levels.

There are three key points for restaurant food refuse relative to rodent prevention: 1) Food refuse should be totally contained in the appropriate Dumpster or compactor and these units themselves must be kept clean and must be kept closed against rodents (and birds, yellow jackets, etc.); 2) Any refuse spillage around any garbage containers must be removed several times daily; and 3) Never, ever, should food refuse or spillage be allowed to remain on the ground overnight. Rats require only an ounce of food every 24 hours to thrive.

Moreover, if rats find more food than they can eat on a given night, they will collect and store food in their nests. In this manner they can survive for up to a week or more without access to new foods, until the next uncleaned spillage event occurs.
 
QUALITY MANAGEMENT PROGRAMS. Again, preventive programs must be emphasized. In a quality pest management service, the technician inspects and records any of the conducive conditions discussed above relative to pest proofing, storage practices and refuse management. The rodent-vulnerable areas of the restaurant should be inspected during each visit. These include the areas listed previously, plus the wall, floor or ceiling voids.

Particular attention should be paid to any warm wall voids with penetrations.
The ceilings must be inspected visually in those areas above heat sources, or along the concrete hollow block walls in areas where lines lead up into the ceilings. For preventative rodent programs in ceilings, rodent monitoring devices should be installed.

Multiple-catch mouse traps (e.g., Kness Pro-Ketch, Woodstream Tin Cats, Bell Laboratories Trapper 24/7, Eaton’s Repeater, etc.) containing a glue trap on the inside floor of the trap, or a rat-size bait station, or the Kness Stick-all Depot Box, containing two Snap-E traps, a Maxforce cockroach bait puck and a fold-up sticky trap. The latter of these traps is so appealing because it is so cost-effective, multi-functional and professional looking.

If the restaurant is subject to rats (both Norway and roof rats will commonly infest ceilings of restaurants) then rat traps can be secured within bait boxes (e.g., T-Rex or Victor snap traps installed into bait stations with ample “head space” to allow for trap operation).

Glue traps have an important role in preventative restaurant rodent control also. But they should serve primarily as monitoring devices, and secondarily as incidental rodent traps. Glue traps should never be the sole and primary rodent control device in urban structures. Yes, glue traps are the least expensive device, and the simplest to install, but in many cases, they are not as effective as snap traps, and there is the risk of “conditioning” those rodents who have survived encounters with the traps to avoid these devices all together.

Depending on location, history and structural designs, some restaurants may not be subject to ceiling rodent activity. In restaurants that have no prior rodent history, the installation of monitoring stations and bait stations into ceilings may not be warranted. However, the ceiling void should always be part of a pest professional’s inspection during the routine servicing, and the negative or positive results recorded on the restaurant’s service sheet.
 
RODENTICIDE PROGRAMS. Some people in both the restaurant industry and in the pest management industry mistakenly believe rodenticidal baits are “illegal” to use inside food-handling establishments (which includes not only restaurants, but food processing plants, warehouses and school kitchen cafeterias). But rodent baits, properly installed, maintained and monitored have an important and, in some cases, essential role in restaurant rodent management programs.

Of course, within the principle of IPM, pesticides should never be the primary approach; baits should only supplement traps and monitoring devices when necessary.

If baits are necessary, they should always be installed into tamper-resistant stations, and only the block bait formulation secured within the stations should be used. Packet-style baits and pellet baits should never be used inside food handling establishments because they are highly prone to being translocated by the rodents into food preparation or food storage areas.

Similarly, under no circumstances should rodenticide tracking powders be used inside or around any restaurant at any time because rodents can carry the powder on their bodies and translocate it wherever they travel.
 
SUMMARY. Call me crazy, but wouldn’t it be great if the entire pest management industry accepted service requests from only those restaurants that were structurally tight, clean and uncluttered? And similarly, wouldn’t it be great if no matter which pest control company a restaurant called from the Yellow Pages, or from a television ad, they knew they were going to get technicians that were going to perform pro-active inspections, advise and counsel on building and sanitation issues, and install their traps and baits in the precise locations to maximize rodent contact and elimination?
 
The author is president of RMC Consulting, Richmond, Ind. and can be reached via e-mail at rcorrigan@giemedia.com.