What happened in Bangkok in late September 2026

According to news reports, between 24 and 27 September 2026 Bangkok received continuous heavy rain of about 300 mm in roughly 48 hours, leaving water standing across many areas. On 26 September 2026 the Bangkok Metropolitan Administration declared all 50 districts a disaster zone. Eastern Bangkok was hit hardest, with Khlong Chan and Bueng Kum among the areas mentioned. Governor Chadchart said the canals were full and drainage would take two to three days after the rain stopped.

Lives were lost during the event, and we extend our sympathies to every affected family. As of 30 September, some roads such as Si Burapha and Lat Phrao still had 20 to 40 cm of standing water. Thai media compared the event with the 2011 floods, and one Thai business report cited a Chamber of Commerce estimate of about 12,300 million baht in damage.

Small bakeries in shophouses are family businesses found in almost every Bangkok neighbourhood. The ground floor holds the shopfront and baking kitchen, and the family lives upstairs. When water enters the ground floor, the damage goes beyond ovens and ingredients. It reaches the hygiene of a food production space, something customers never see but experience in every pastry they take home.

A typical scenario: the Lat Phrao bread shop that went quiet for a week

(This is a typical scenario compiled from common post-flood situations. It is not a statement from a real person.)

Every morning from 5 a.m., the smell of butter and fresh bread drifts down a soi off Lat Phrao from Mint's bakery. Her single-unit shophouse sells wholewheat loaves, croissants, cake slices and cookies to neighbours and to office workers waiting for the bus at the mouth of the soi. The ground floor is split between a small shopfront with a glass display case and, at the back, a kitchen with a two-deck electric oven, a dough proofer, a mixer, stainless steel tables and a corner for sacks of flour, sugar and dry goods. The family lives on the second and third floors.

On the night of 25 September, water from Lat Phrao Road, which could not drain fast enough, backed up into the soi and seeped through the folding steel gate. Mint and her husband carried some flour bags upstairs, but the sacks on low plastic pallets in the kitchen corner were fully soaked. Water stood ankle-to-shin deep on the kitchen floor for two days. The ground-floor power was cut, and the refrigerator holding butter, cream and eggs went off with it.

When the water receded, the kitchen that used to smell of butter smelled of damp and spoiled milk. Thin mud clung to the legs of the stainless tables, the base of the proofer was water-stained, the lower plaster walls were damp in a band, and grey silt had settled into the floor grout. Within two or three days, tiny black spots appeared on the wall corner behind the refrigerator.

Regular customers messaged daily asking when she would reopen. Mint wanted to bake again as soon as possible, because every closed day was lost income. But as a food maker, she knew that bread is one of mold's favourite foods. If spores were still floating in the kitchen, her loaves might go moldy faster than usual, and that is the last thing any bakery wants a customer to find.

Why shophouse bakery kitchens face high mold and bacteria risk after a flood

1. Bakery ingredients are mold food

Flour, sugar, milk, butter, eggs, dried fruit and finished bread are all excellent food for mold. In any working bakery, fine flour dust settles in machine crevices, on shelves and in wall joints. When floodwater wets that dust and leaves it in damp air, it gives mold both food and water at once. Mold can start growing on wet materials within roughly 24 to 48 hours, according to general CDC and WHO guidance.

2. Floodwater carries drain germs into a food production area

Floodwater in shophouse sois usually contains sewage from drains, which may carry faecal bacteria such as E. coli and leptospira from rat urine, the cause of leptospirosis. Shophouse kitchens also tend to have floor drains and grease traps, which can back up during flooding and spread old grease and food waste mixed with sewage across the kitchen floor.

3. Bakery equipment is full of crevices and enclosed spaces

A dough proofer is designed to stay warm and humid. A mixer has a base and joints where flour and water collect. Ovens have vents and undersides. Display cases have tracks and rubber seals. Tray racks have wheels and hollow tube posts. All of these readily trap moisture and silt after the water drops.

4. Shophouses ventilate poorly and hold moisture for a long time

Most shophouses have few windows, and the kitchen at the back gets little airflow. Plaster walls that wick water up from below release that moisture slowly over days or weeks, keeping kitchen humidity high even after the floor looks dry.

5. The family lives upstairs, so the risk does not stop at the shop

Spores and musty air from the ground-floor kitchen rise up the stairwell into the family's bedrooms. With older relatives, young children or allergic family members at home, a damp ground floor raises the risk for the whole household.

Symptoms to watch and who is most at risk

Breathing mold spores and damp air can cause a blocked nose, sneezing, coughing, eye and skin irritation, and may trigger asthma or allergies. Touching contaminated surfaces or eating food contaminated by sewage may cause diarrhoea, stomach pain, nausea or vomiting. Older people, young children, pregnant women, people with chronic illness and those with weak immunity need extra care, and they are also among a bakery's customers.

Important: If an owner, staff member or family member who waded through floodwater develops fever, muscle pain (especially in the calves), red eyes, diarrhoea or an inflamed wound, they should see a doctor promptly and mention the exposure. Anyone with diarrhoea or vomiting should not handle food until fully recovered. Ozone treatment is not medical treatment.

What happens if a bakery starts baking before recovery is complete

Customer health

Food from a kitchen that is still contaminated can put customers at risk, especially children and older people. Items that are not heated again after decorating, such as cream, cake toppings and fresh fruit, need a genuinely clean production space.

Money and ingredients

Flooded ingredients must be thrown away regardless. If spores are still in the air, though, new flour and ingredients may spoil faster, and finished goods may have a shorter shelf life. More unsold goods end up in the bin, eating into already thin margins.

Time

Reopen too early and then close again after finding new mold behind a fridge or receiving a complaint, and the shop loses time cleaning twice and misses the moment when the neighbourhood is returning to normal life.

Reputation

For a bakery, one photo of bread that went moldy unusually fast, posted on social media, or a review saying the shop smells musty, can undo years of trust. Small soi shops live on regulars and word of mouth. Reputation is their most valuable asset.

Family

A shophouse bakery is also the owner's home. Damp and mold in the ground-floor kitchen hit income and family health at the same time, so restoring the ground floor properly protects both the business and the household.

Why the usual small-shop fixes fall short

Washing the stainless tables and calling it clean: Stainless steel is easy to wash, but most of the risk sits where you cannot see: under the oven, behind the fridge, in the proofer door tracks, in floor grout and in the kitchen air.

Strong bleach everywhere: Bleach is useful on washed surfaces, but should not be overused in a food production area. It must be rinsed per the label, chlorine smells can taint ingredients or the aroma of baked goods, and it cannot reach the air or deep crevices.

Running the oven to drive out moisture: Oven heat warms the room but does not dry walls and corners evenly, and may briefly raise humidity in a way that helps mold grow faster in some spots.

Scented candles or baking smells to cover the odour: The smell of butter may mask mustiness during the day, but it does nothing about the microbes behind it. The musty smell is back every morning when the shutter opens.

Repainting the kitchen walls right away: Plaster that absorbed water keeps releasing moisture for a long time. Painting too soon traps mold under the paint, which may later flake into the production area.

The shared limit is that none of these methods can treat the surfaces, deep crevices and air of the whole kitchen at once. That is the gap ozone treatment fills, after the kitchen has been washed and dried.

WHD ozone disinfection for shophouse bakeries

According to World Health Disinfection (WHD), ozone (O3) is a fast-reacting gas. Released into a closed room at a concentration set by the technician, it spreads through the shopfront, kitchen, ingredient store and the gaps behind machines that hands cannot reach. Ozone breaks down the cell structures of viruses, bacteria and mold and breaks apart musty odour molecules, then reverts to oxygen (O2) without leaving chemical residue. According to the test results certified for the company by Thailand's Department of Medical Sciences and Intertek (UK), it eliminates viruses, bacteria and mold at 99.99%.

How the work runs in a bakery

1. Site survey: The team checks the size of the shopfront, kitchen, ingredient store, toilet and the stairwell connecting to the floors above, then plans zones and how to seal them.
2. Confirm the kitchen is washed and dry: Flooded ingredients have been discarded, mud washed out, equipment and food-contact surfaces washed and sanitised according to food hygiene guidance, swollen materials removed, and the kitchen reasonably dry. Ozone is an extra step after cleaning, never a substitute.
3. Remove all food and ingredients: Baked goods, flour, sugar, butter, cream and every ingredient leave the treatment zone, along with plants and pets.
4. Empty and seal the space: No people in the treatment zone. The steel gate is closed, exhaust fans and air conditioning are switched off temporarily, and the stairwell is sealed so ozone cannot reach occupied floors, or the family leaves the building during treatment as the technician advises.
5. Release ozone and hold contact time: The generator runs according to the volume of the space, with a typical cycle of about 30 minutes per zone.
6. Rest and ventilate: Wait for the ozone to revert to oxygen, ventilate, then re-enter at the time the technician specifies. Before baking, wash food-contact surfaces once more as part of the shop's normal routine.

For ozone jobs of 15,000 baht or more, WHD currently includes a free medical-grade disinfectant spray, which the shop can use on non-food-contact points such as door handles, the cash counter and light switches, following the label.

If the shop is repainting or installing new shopfront furniture that leaves a chemical smell, see WHD's ozone chemical-residue and odour removal service. For general surface disinfection after mud removal, see the Chemgene HLD4H medical-grade disinfectant.

10 reasons a bakery should consider ozone before firing up the ovens again

1. It reduces airborne mold spores, the number one enemy of bread and cake, lowering the chance of goods going moldy unusually fast.
2. It reaches behind ovens, under fridges and inside proofer gaps, places that are hard to clean by hand.
3. It leaves no chemical residue or smell, because ozone reverts to oxygen, so it will not interfere with the aroma of butter and baking. See the residential and building ozone disinfection service.
4. It tackles musty and drain smells at the source, so the shopfront smells of real baking, not of one smell covering another.
5. It protects new ingredients. With less mold in the store, new flour and sugar can be kept with more confidence.
6. Each zone is quick. A typical cycle of about 30 minutes per zone means it fits into the days the shop is still closed.
7. It is backed by test results certified for the company by the Department of Medical Sciences and Intertek (UK).
8. It helps protect the family upstairs by reducing spores that would otherwise drift up to the bedrooms.
9. It shows customers you care. The shop can say its kitchen was washed, dried and disinfected before reopening.
10. It can become a yearly hygiene routine, with kitchen ozone treatment booked each rainy season. Details are on the ozone service page.

Before and after: a bakery kitchen transformed

Example case: a Bueng Kum home-style cake shop that reopened step by step

(An illustrative example to explain the process, not a verified customer review.)

Puk runs a home-style cake and custard-bread shop in a Bueng Kum shophouse with her daughter, who handles online orders. During the flood, water entered the ground floor and stayed for several days, because the nearby canal was full and could not drain in time.

When the water dropped, Puk's first step was to discard every ingredient that had touched floodwater or sat in a refrigerator without power for a long time: flour, sugar, milk, butter, eggs and pre-made custard. Some bags looked dry on the outside, but she chose not to take the risk. The family then shovelled out mud, washed the floor, scrubbed the grout, took every tray rack apart for washing, cleaned the inside and outside of the fridge and proofer, and washed and sanitised tables, tools and food-contact containers following food hygiene guidance.

A wooden shelf used for cake boxes had swollen and smelled musty, so it was thrown out and replaced with stainless steel. The lower plaster walls were left to dry with fans and a dehumidifier for several days before any decision about repainting. An electrician checked the ground-floor wiring and the oven before use.

Once the kitchen was properly dry, Puk booked WHD to treat the shopfront, kitchen and storeroom. The family moved newly bought ingredients to a relative's house for the day, sealed the stairwell as the technician advised, and went out for a meal during treatment and the rest period. When they returned after the time the technician gave, the musty smell that had drifted up to the second floor was noticeably reduced.

Before reopening, Puk washed all food-contact surfaces once more and baked a test batch to watch its shelf life. Once satisfied, she announced the reopening on her page with a short note on the recovery steps. Several regulars came back and said they appreciated the shop taking cleanliness seriously before selling again.

Recovery checklist for shophouse bakeries

Before ozone treatment

• Have an electrician check wiring, ovens, proofers and mixers before use. Do not plug in any submerged appliance until it has been checked.
• Discard all food and ingredients that touched floodwater, plus chilled food from fridges that lost power for a long time, following Department of Health guidance.
• Wear rubber gloves, boots and a mask while cleaning.
• Shovel out mud, wash the floor, scrub the grout and flush floor drains and grease traps.
• Remove tray racks, proofer tracks and detachable parts and wash every piece.
• Clean inside and outside the fridge, freezer and display case.
• Wash and sanitise food-contact surfaces and utensils according to food hygiene guidance.
• Remove swollen, musty wooden shelves, plywood and similar materials.
• Have air conditioner coils and drain pans cleaned, and clean the exhaust fan.
• Dry the kitchen with ventilation or a dehumidifier before the appointment.
• Move all food, ingredients, plants and pets out of the treatment zone.

During and after ozone treatment

• No people, pets or plants in the treatment zone. Seal the stairwell or have the family leave the building as the technician advises.
• Wait for the full rest period, then ventilate before entering.
• Wash food-contact surfaces again before production.
• Bake a test batch and watch its shelf life before full reopening.
• Control humidity in the kitchen and store. Keep flour in sealed containers raised off the floor.
• Check wall corners and behind appliances for new mold over the following week.

Frequently asked questions

1. After ozone, can I use flour that got wet?

No. Ingredients and food that touched floodwater must be thrown away. Ozone treats a space that has already been washed and dried. It does not make contaminated food safe again.

2. Must baked goods and ingredients leave during treatment?

Yes. All food and ingredients must leave the treatment zone, so the space is empty of people, pets, plants and food. Bring them back after the rest and ventilation period.

3. Does the family upstairs need to leave?

It depends on the building layout and how well the stairwell can be sealed. The team will assess on site and advise whether to seal off areas or have the family leave during treatment and rest.

4. Can ozone replace washing tables and baking tools?

No. Food-contact surfaces must always be washed and sanitised according to food hygiene guidance. Ozone is an extra step for the air and hard-to-reach corners.

5. How long does it take, and when can I reopen?

A typical cycle is about 30 minutes per zone, plus the rest and ventilation time the technician specifies. Most shops can complete it in a single day while still closed.

6. A staff member has diarrhoea after cleaning. What now?

They should see a doctor, mention floodwater exposure and avoid handling food until fully recovered. Ozone treatment is not medical treatment.

Bring back the smell of fresh baking, with no mustiness hiding behind it

Talk to the WHD team about ozone disinfection for bakeries, baking kitchens and ingredient stores in shophouses after the Bangkok floods 2026.

Get Advice on Bakery Ozone Disinfection

Call 065-556-6294 · LINE @whd268 · Email worldhealthdisinfection@gmail.com

Related services

• Residential and building ozone disinfection
• Ozone chemical-residue and odour removal
• Chemgene HLD4H medical-grade disinfectant

References

• 2026 Bangkok floods – Wikipedia
• Al Jazeera: Disaster zone declared across Bangkok
• CDC – Floods and cleanup
• Thailand Department of Health (Anamai)