If you’re overseeing a food production site, you already know that pest activity is more than a nuisance — it’s a serious compliance risk. The presence of pests, such as rodents, flies, cockroaches, or stored product insects, can result in contamination, failed audits, product recalls, and even shutdowns.
Recognising the early signs of pest infestation is key to staying compliant and protecting your reputation. This guide covers the 10 most common warning signs to look out for, along with the pests most likely to be responsible for each one.
However, first, let’s examine the usual suspects in a food production setting.
Common Pests in Food Manufacturing Environments
Food facilities offer everything pests love: warmth, shelter, moisture, and, of course, food. Some of the most common intruders include:
- Rodents (rats and mice): attracted to food product, waste spillage, water spillage, warmth, seeking harbourage and nesting in walls or equipment voids.
- Flies ( fruit flies, houseflies, and drain flies): drawn to food waste, sugary residues, and drains.
- Wasps: more seasonal, but dangerous and disruptive near waste or sugary products.
- Cockroaches: hiding in dark, moist areas, contaminating surfaces and packaging.
- Ants: follow trails to sugary or greasy food sources.
- Moths: Infesting raw materials and stored products.
- Beetles and weevils: infest flour, cereals, nuts, and other dry goods.
Now that you know what you’re up against, let’s look at the top 10 indicators that pests may be present.
1. Damage to Products or Packaging
Torn packaging, chewed boxes, or holes in products are some of the most evident signs of pest activity. Rodents often gnaw through packaging, while stored product insects, such as weevils or beetles, may be found inside flour, rice, or cereals.
Keep an eye out for:
- Gnaw marks on cardboard or plastic
- Holes in food packaging
- Larvae or webbing inside or close to||| dry goods (a moth or beetle giveaway)
2. Visible Sightings of Pests
Pest sightings should never be ignored. A single cockroach or mouse spotted during production could indicate a much larger, hidden infestation.
Sightings to take seriously:
- Mice or rats scurrying along walls (especially during quiet hours)
- Flies hovering near drains or bins
- Cockroaches; crawling in production
- Wasps nesting near loading docks or waste zones
3. Droppings
Droppings are a telltale clue that can even help identify the specific pest you’re dealing with.
Examples:
- Rodent droppings: small, dark, and pellet-shaped
- Cockroach droppings: resemble black pepper or coffee grounds
- Fly specks: often found on walls or near light fixtures
Ideally, get a sample of any droppings and show them to your pest control expert. Make sure your team knows the importance of cleanliness, but also reports the droppings so they can be recorded.
4. Smear Marks and Grease Trails
Rodents tend to follow the same routes along walls and equipment, leaving behind dirty smear marks or greasy trails from their fur. These marks often appear near baseboards or pipework and are a classic indicator of repeated movement.
5. Strange or Unpleasant Odours
Certain pests give off distinctive smells. For example:
- A musky ammonia-like smell can point to a rodent infestation
- Cockroaches produce an oily, unpleasant odour
- Accumulated dead insects or waste in drains may be accompanied by a sour or rotting smell
Unusual odours should always be investigated promptly.
6. Damage to Facilities and Infrastructure
Pests can do more than contaminate products — they can damage the building itself.
Watch for:
- Gnawed electrical cables (a serious fire risk from rodents)
- Chewed insulation or packaging foam
- Holes or burrows around the perimeter (possible rodent entry points)
7. Webbing, Larvae or Pupae in Stored Goods
This sign is most associated with moths and beetles. Indian meal moths, for example, leave behind webbing and larvae in grains and flour.
You might find:
- Silk-like threads inside food containers
- Small maggot-like larvae in flour or cereal bins
- Empty pupal casings near storage areas
8. Insect Body Parts or Shed Skins
Some pests leave behind more subtle clues, especially during moulting or breeding.
Check for:
- Shed cockroach skins in cracks or under equipment
- Dead beetles or weevils in dry goods
- Detached insect wings around windowsills or lights
These fragments often point to a growing infestation.
9. Nesting Materials or Nests
Some pests leave behind more subtle clues, especially during moulting or breeding.
Check for:
- Shed cockroach skins in cracks or under equipment
- Dead beetles or weevils in dry goods
- Detached insect wings around windowsills or lights
These fragments often point to a growing infestation.
10. Unusual Behaviour in Staff or Pests
Lastly, your team might notice signs before a formal inspection ever does.
Examples include:
- Staff reporting frequent fly sightings or bites
- Increased bird activity near external loading bays
- Pests behaving oddly — for example, flies active at night or cockroaches seen in daylight (a sign of overcrowding)
Encourage your team to report anything unusual immediately.
Conclusion: Be Proactive, Not Reactive
In a food production setting, being aware of the early signs of pest infestation is part of your frontline defence. Regular inspections, staff training, and a strong relationship with your pest control provider are crucial to preventing minor issues from escalating into major incidents.
If you’re noticing any of the signs mentioned above, it’s time to take action. Don’t wait for a failed audit or customer complaint — schedule a professional site assessment and keep your standards where they belong: safe, clean, and compliant.
Need help identifying or addressing a potential pest issue? Contact our expert team for a site visit today.
Our hub has been in Lincolnshire since we started but we operate throughout the country and some of our advisors see very little of our home county. Here are a few of the places we currently cover with active projects and maintenance contracts:
