A 220-Staff Food Plant Where Three Flies in the Packing Room Cost 4.6 Million Baht in Orders
Last updated: 7 Sep 2026 | 3 Views |
A single fly in an audit report can be worth millions of baht
A 220-Staff Food Plant Where Three Flies in the Packing Room Cost 4.6 Million Baht in Orders
Why controlling the inside of the building is not enough, and why factories must control the ground outside it
The auditor did not count how many flies there were. He recorded that flies were found in the production area — and that one sentence removed a year of orders.
Khun Wichai is 51 and manages a ready meals plant in Lam Luk Ka, Pathum Thani, with 220 staff, producing under its own brand and for two modern trade customers.
The plant has held GMP and HACCP certification for nine years. Air curtains on every door, 18 electric insect light traps, and a strict daily hygiene inspection routine.
In August 2025 an unannounced audit by a major modern trade customer recorded one significant non-conformity: three flies observed in the packing area. The customer suspended purchasing immediately pending corrective action — 4.6 million baht of orders.
Three insects that stopped a year of orders
When the auditor called him over to the location, Khun Wichai expected it to be the waste room or the wash-up area. It was the packing area — the cleanest zone in the plant.
He pointed out that every door has an air curtain and that insect light traps are installed throughout. The auditor said he understood, but that his job was to record what he saw, and what he saw was three flies in the packing area.
Under food safety standards, insects found in a production area are a significant non-conformity regardless of number, because even one means the preventive system has a gap.
The customer suspended acceptance of goods and requested a corrective and preventive action report within 21 days. The suspended orders were worth 4.6 million baht, and the customer's own line had to stop in the meantime.
Where the flies came from, with every gap already sealed
Khun Wichai brought in a food industry pest management consultant to review the whole system, and what the consultant showed him reframed the problem completely.
Every measure the plant had — air curtains, light traps, sealed gaps — is a defensive measure. It waits for the insect to arrive at the door and then blocks it, which works only while external pressure is low.
Surveying the surroundings, external pressure turned out to be very high. A drainage canal runs behind the plant, there is overgrown vacant land alongside, a mid-sized pig farm sits 400 metres away, and a community waste transfer point lies within a kilometre.
The consultant's summary was that the plant was holding back a flood with a bath towel. While the fly population around the building stays at that level, opening the raw material doors dozens of times a day is enough for insects to get in.
The costs that followed
The suspended orders were 4.6 million baht. What hurt more, Khun Wichai says, was what came next: the customer cut its order share by 35 percent the following quarter to spread risk across other manufacturers.
The plant paid a consultant and prepared the corrective action report at about 180,000 baht, and hosted two re-audits with the plant covering the audit team's travel costs.
Operationally, stopping the line for three days for a deep clean and full system review cost roughly 1.2 million baht of lost production.
What kept him awake, he says, is that he knew his plant genuinely was clean and his team had followed every step — and that none of it was arguable once an auditor saw a fly in front of him.
What changed was extending the perimeter outward
The consultant proposed several measures, but the one Khun Wichai says changed the situation most was starting to control the insect population around the building rather than only at the door.
The plant bought two AIROFOG AT35 thermal foggers and set a twice-weekly perimeter schedule covering the boundary fence, the canal edge, the neighbouring vacant land where permitted, the raw material receiving yard and the area around the waste room.
Fogging is done in the evening after the line shuts down, taking about an hour and a half per round with two staff, with the date, area and chemical recorded every time as documentation for the HACCP system.
At the second re-audit — again unannounced — no insects were found in the production area, and the customer approved a return to full order volumes the following month.
What it actually costs
In food standards, the count does not matter — the finding does
The auditor did not record how many flies. He recorded that flies were found in the production area, which is automatically a significant non-conformity, because it means the preventive system has a gap.
A suspended order is followed by a permanent share reduction
Beyond the 4.6 million baht suspended, the customer cut its order share by 35 percent the following quarter to spread risk — damage that continues for several quarters.
The cost of corrective action and stopped production
About 180,000 baht for the consultant and the report, plus three days of stopped line for a deep clean, costing roughly 1.2 million baht in lost production.
The best internal measures still lose to external pressure
Air curtains, light traps and sealed gaps are defensive measures that work while the insect population outside is low. With heavy pressure outside, opening the raw material doors dozens of times a day is enough.
Why the usual fixes do not work
Air curtains on every door
Necessary and worth having, but they work at full effectiveness only with normal door cycling and stable air pressure. On heavy receiving days with doors held open, effectiveness drops sharply.
Multiple electric insect light traps
They do catch insects that get in and provide good audit evidence. But they are an end-of-pipe measure: they do not reduce the number of insects trying to enter, and they do not help in the second an auditor sees one flying.
Increasing internal cleaning frequency
The plant was already clean, and more cleaning does not reduce external pressure. The problem was never internal soil; it was a fly population outside that exceeded what the door defences could hold.
Glue traps and baits around the building
They reduce numbers somewhat and are excellent for monitoring population trends. But their capacity to reduce an actual population is tiny against a fly laying hundreds of eggs at a time.
Asking neighbours to manage their waste
Worth doing, but not controllable in practice. A factory has no authority over a farm, vacant land or a community waste point — so it needs a measure it controls 100 percent itself.
If the best internal control is still not enough, the external pressure has to come down
What the consultant showed Khun Wichai is that the plant's defences were designed for a certain level of pressure. Above that level, the same system leaks — no matter how well the team follows procedure.
The answer is therefore not another layer at the door. It is reducing the number of insects that reach the door in the first place, which means managing the ground around the building systematically and consistently.
A thermal fogger is the tool best suited to this, because very fine droplets drift into the boundary fence line, shrubs, canal edge, the space under pallet racking and the corners around the building where flies rest — places coarse spray and traps cannot reach.
The AIROFOG AT35 is a shoulder-carried thermal fogger with a 100 percent stainless steel body that resists the chemical corrosion which is the leading cause of failure. It runs both water-based and oil-based chemicals, is light enough for two staff to cover the perimeter in one round, is certified in Germany and the UK, and is backed by a service centre with genuine parts in Thailand — so the plant controls its own fogging schedule without waiting on a contractor.
10 reasons the AIROFOG AT35 thermal fogger solves it
1. It reduces external pressure, which is the real root cause
Every measure at the door works only while the population outside is low. Routine perimeter fogging reduces the number of insects reaching the door in the first place.
2. Fog penetrates fence lines, shrubs and canal edges
Flies rest along fence lines, in shrubs, under pallet racking and beside water. Traps and coarse spray cannot reach those places; very fine thermal fog matches the insects' actual behaviour.
3. The plant controls its own schedule, 100 percent
Under food standards, auditors want measures that are controllable and documented. Owning the machine lets the plant fog to its own schedule and add rounds immediately when monitoring shows a warning sign.
4. It generates GMP and HACCP documentation
Recording the date, area, chemical and operator every time is the evidence that shows an auditor you have a proactive vector control measure, not only passive defences at the door.
5. 100 percent stainless steel body resists chemicals
Chemical corrosion is the leading cause of fogger failure. An all-stainless body extends life and cuts workshop days — which matters when fogging is part of your quality system.
6. Runs both water-based and oil-based chemicals
The plant can select product and formulation by species and consultant guidance, without buying two machines and without risking damage from the wrong product type.
7. Light enough for two staff to cover the perimeter in one round
Perimeter fogging means walking the fence line and surrounding ground over a long distance. Machine weight determines whether the team completes the area in a single round.
8. Certified in Germany and the UK
Verifiable certification is something the QA team can attach to a corrective and preventive action report — quite different from simply stating that the plant sprays for insects.
9. Service centre and genuine parts inside Thailand
Once fogging is a control measure in your quality system, an unusable machine means an interrupted measure and a finding at the next audit. Local service is part of risk management.
10. Useful for perimeter disinfection as well
Beyond insect control, a thermal fogger disinfects the receiving yard, waste room and common areas — so one machine supports several sanitation needs.
Before the thermal fogger
- An auditor finding 3 flies in the packing area, recorded as a significant non-conformity
- A modern trade customer suspending 4.6 million baht of orders immediately
- The customer cutting its order share by 35 percent the following quarter
- About 180,000 baht for consultancy and the corrective action report
- Three days of stopped production for a deep clean, costing roughly 1.2 million baht
- A drainage canal, vacant land, a pig farm and a community waste point all within a kilometre
After the thermal fogger
- An unannounced re-audit finding no insects in the production area at all
- The customer approving a return to full order volumes the following month
- Twice-weekly perimeter fogging, about 90 minutes per round with two staff
- Date, area and chemical recorded every time as HACCP documentation
- Insect light trap catches inside the building down more than 70 percent in two months
- The plant controlling its own fogging schedule without waiting on a contractor
The three-step process
1. Survey the perimeter and identify sources
Walk the radius around the plant to identify breeding and resting sites — fence lines, shrubs, canal edges, the waste room, the receiving yard and neighbouring vacant land — then set a route that covers them.
2. Prepare the machine and chemical to your quality system
Check the machine before use, mix a registered product to the specified ratio, and prepare the record form to match your GMP and HACCP documentation requirements.
3. Fog outside production hours and record the result
Fog in the evening after the line shuts down so production areas are unaffected. Flush and clean the machine after every use, and record date, area, chemical and operator as evidence.
From someone who uses one
My plant genuinely is clean and my team follows every step. But when the auditor saw three flies in the packing area, no argument was available. The consultant told me we were holding back a flood with a bath towel, because we have a canal, vacant land and a farm around us. Once we started fogging our own perimeter twice a week, trap catches inside the building fell seventy percent and we passed the re-audit.
Khun Wichai P. — plant manager, ready meals factory, Pathum Thani
Why flies are harder to solve than mosquitoes in a food plant
A female house fly lays 100 to 150 eggs at a time and does so five or six times in her life, with an egg-to-adult cycle of just 7 to 10 days in Thailand's heat.
Fly breeding sites are decomposing organic material: waste piles, animal manure, food waste and sludge in drainage channels. These sites are usually outside the factory fence and entirely beyond the factory's control.
Flies also travel further than most people assume. Research puts house fly foraging range at one to three kilometres from the breeding site, which means a farm or waste point several hundred metres away is a genuine source of your problem.
For this reason, fly management in a food plant always needs two layers: defence at the building, and population reduction in the surrounding area. Most plants invest heavily in the first and neglect the second.
What auditors want to see in a corrective action report
Khun Wichai says his most valuable lesson was not about insect control but about understanding what an auditor wants to see.
First, a credible root cause. Identifying that external pressure exceeded the capacity of the door defences is an analysis an auditor accepts immediately — quite different from promising to be more careful.
Second, a measure that matches that cause. If the cause is a high population around the building, the measure has to reduce that population, which makes routine perimeter fogging the logically consistent answer.
Third, verifiable evidence: fogging records for every round, equipment certification, chemical registration documents, and monitoring data on internal trap catches before and after. With all three, the customer restored full order volumes within a month.
Frequently asked questions
Can we fog the perimeter without affecting production areas?
Yes — fog outside production hours and close air intakes during the round. Our team advises on the route and timing that suit your layout so no fog enters production or raw material storage areas.
How often should we fog?
For plants near breeding sources, once or twice a week, because that is shorter than the 7 to 10 day fly life cycle. Lower-pressure sites may move to fortnightly and monitor results through internal trap catches.
Can it be used as GMP and HACCP evidence?
Yes. Record date, area fogged, chemical and ratio, and operator every time, and attach equipment certification and chemical registration documents — WHD can supply the supporting paperwork.
What chemicals are used and is there residue?
Only properly registered products, used outdoors only. Our team advises on type and ratio and sets the safe re-entry interval according to the product label.
What area does one machine cover?
It depends on layout and fence line distance. Most mid-sized plants use one or two machines per round with two staff. We assess this from your site plan and the walking distance involved.
Can factory staff operate it themselves?
Yes. WHD provides operating, chemical mixing and maintenance training on delivery, plus guidance on personal protective equipment for operators.
What if the machine fails during an audit period?
WHD runs a service centre with 100 percent genuine model-specific parts and technicians with over 10 years' experience in Thailand, and always diagnoses and quotes before repairing — which reduces the risk of an interrupted control measure.
How do we order or get a quotation?
Call 065-556-6294 or add LINE @whd268. Our team will assess the number of machines from your site plan, prepare a quotation, and supply certification documents for your quality system.
You already control the inside. What is left is what sits outside the fence.
If your plant has passed audits for years and is suddenly written up for insects, the problem is usually not internal cleanliness. It is a population outside the building that exceeds what your door defences can hold.
The AIROFOG AT35 thermal fogger has a 100 percent stainless steel body, runs both water-based and oil-based chemicals, is light to carry, is certified in Germany and the UK, and is backed by a service centre with genuine parts in Thailand — so your plant controls its own perimeter schedule with complete documentation for the quality system.
The WHD team will assess the number of machines from your site plan. Call 065-556-6294 or add LINE @whd268.
Thermal foggers and ULV sprayers for food factories, warehouses, farms, hotels, government agencies and private business across Thailand
See the machine and pricing — click here
Call 065-556-6294 or add LINE @whd268
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