The rodent programme is the first thing most food safety auditors want to walk, and the site map is how they walk it. They take the numbered plan off the wall, start at station 1 and follow the line. If the numbers on the map match the numbers on the floor, and the service records match both, the review is over in ten minutes. If station 14 is on the map but nowhere on the boundary, or there is a bait box behind the dispatch dock that has no number and appears on no route, the auditor now has a thread to pull. This article is about building the grid and the map so there is no thread to pull.
The principles here follow SANS 10133 and the integrated pest management expectations of the major food safety schemes. Nothing below replaces a site-specific risk assessment: the assessment is what justifies every number and every interval you choose.
Key takeaways
- External toxic stations form a perimeter grid, typically 15 to 30 metres apart, tightened at gates, refuse and water sources.
- Internal points are non-toxic monitoring only: no rodenticide inside production, storage or packing zones.
- Number stations in a logical, continuous sequence that follows the service route, and never re-use a retired number.
- Every station on the map must exist on the floor, and every station on the floor must exist on the map. Auditors check both directions.
- External stations must be lockable and tamper-resistant, secured to the ground or wall, and opened only with the correct key.
The external perimeter grid
Rodents approach a building from outside, so the first line of defence is a ring of toxic, tamper-resistant stations around the external boundary and along the building line. The aim is to intercept Rattus norvegicus, Rattus rattus and Mus musculus before they reach the wall. This perimeter-first design is the backbone of our rodent control programmes.
As a working guide, place perimeter stations at 15 to 30 metre intervals along fences and the outside face of the building. Tighten that to 10 to 15 metres at higher-pressure points: vehicle gates, refuse and skip areas, the raw material intake, external drains, and anywhere water collects. The exact interval is a decision the risk assessment records, not a number pulled from the air, and an auditor will ask you to justify why a stretch of boundary near a stormwater canal has the same spacing as a quiet office wall.
Position each station flush against a vertical surface, on the rodent runway where wall meets ground, with the entry holes facing the wall. Rodents travel with a flank against a surface, so a station marooned in the open middle of a yard catches nothing and tells the auditor the placement was not thought through.
Internal monitoring points and non-toxic bait
Inside the building the philosophy flips. The internal programme is detection-led, not kill-led. Stations inside production, storage, packing and dispatch hold non-toxic monitoring blocks (often a coloured wax breakblock), glue boards or snap traps, never rodenticide. There are two reasons. First, a rodent that takes poison inside a food zone can die and decompose in a wall cavity or under a line, creating a contamination and odour problem inside the very area you are protecting. Second, non-toxic blocks are a cleaner monitoring signal: gnaw marks tell you a rodent has entered without the confounding effect of a bait that may have been eaten elsewhere.
Space internal monitors at roughly 10 to 20 metre intervals along internal walls, and add points at every credible entry route: beside personnel and roller doors, near the dock levellers, along service-duct penetrations, and at the internal face of external drains. Read them alongside your insect light trap line so the whole monitoring picture reconciles.
Numbering the stations
A number is a control. Every station carries a permanent, unique identifier fixed to the station and marked on the floor or wall beside it, and that identifier is what the technician scans and records at each visit. Get the numbering discipline right and the rest of the programme falls into place.
- Continuous and logical. Number in the order the service route runs, so the technician moves 1, 2, 3 around the perimeter and then through the interior without backtracking. A route that follows the numbers is faster and far less likely to skip a station.
- Separate the series if it helps. Many sites use a prefix to distinguish device types, for example EB for external bait stations, IM for internal monitors, ILT for insect light traps. This keeps the map legible and the trend reports readable.
- Never re-use a retired number. If station 12 is removed because a wall was rebuilt, retire the number. Do not silently move 12 to a new position, because a year of trend data is attached to that identifier and moving it corrupts the history.
- One number, one location, one record. The identifier, the map position and the service history must all point to the same physical box.
The site map that must match the floor
The map is the master document. It is a scaled or clearly proportioned plan of the site showing every external station, every internal monitor, every insect light trap, every pheromone monitor and any bird control point, each in its true position and labelled with its number. It carries a version number and a date, and it is reissued whenever a station is added, moved or retired. That is the discipline our manufacturing pest control programmes apply as standard, because a factory that cannot produce a current map cannot pass the walk.
The single test an auditor applies is reconciliation in both directions:
| Direction of check | What it proves | What a mismatch signals |
|---|---|---|
| Map to floor: every numbered station on the plan is physically present. | The programme is complete and maintained. | A "ghost" station: the plan is out of date or the box was removed and never replaced. |
| Floor to map: every box on site appears on the plan with a number. | Nothing is uncontrolled. | An "orphan" station: unnumbered, off-route, never serviced or trended. |
Both failures are common and both are avoidable. The ghost usually appears when a contractor removes a damaged station and forgets to reissue the map. The orphan usually appears when a well-meaning site team member buys a bait box from a hardware shop and puts it behind the canteen. Neither belongs in a controlled programme.
Tamper-resistant stations and access control
External stations must be lockable and tamper-resistant, opened only with the manufacturer's key or tool, and secured against being moved, kicked over or picked up. Fix each one down: bolt it to a concrete plinth, weight it, or bracket it to the wall. A station that can be flipped open by a child or blown across the yard is neither safe nor auditable.
Keep the keys controlled and record who holds them. When an auditor opens a station they expect to find it clean, correctly baited, the block secured on its rod, and a legible service label or scan point. Loose blocks rattling in the bottom of the box, spilled bait, or a station full of dust and dead insects all read as neglect regardless of what the paperwork says.
Tying it to the record
A numbered grid and a matching map are only half the job. Each visit must record, per station, that it was checked, what was found (clean, activity, gnawing, droppings, a catch), what action was taken, and the product or device present. On ASC food and beverage contracts this is captured digitally at station level in myASConline, so the trend for station 14 over twelve months is one click away and the map, the route and the history can never drift apart. Free template maps and station logs are on our free checklists and forms page, and the rodents themselves are covered in the pest species guide.
Frequently asked questions
How far apart should rodent bait stations be spaced around a food facility?
External perimeter stations are typically 15 to 30 metres apart, tightened to 10 to 15 metres at gates, refuse areas and water sources. Internal monitors sit at roughly 10 to 20 metre intervals and at every likely entry route. The intervals must be justified by the site risk assessment and recorded.
Should bait stations inside a food factory contain rodenticide?
No. Internal points use non-toxic monitoring blocks, glue or snap devices. Toxic rodenticide is confined to lockable, tamper-resistant stations on the external perimeter, so no poisoned rodent can die and decompose inside a food zone.
Why must every station on the map exist on the floor and vice versa?
The map is the control document. A station on the map but not the floor reads as an unmaintained programme; a station on the floor but not the map is uncontrolled and untrended. Auditors walk the line with the map and check both directions, so they must reconcile exactly.
