Please note: this is general health information, not diagnosis or treatment. If you have symptoms of food poisoning, consult a doctor or pharmacist. Disinfection spraying cleans surfaces; it does not treat illness and does not make contaminated food safe to eat.

Example case: the big pot of curry cooked before the power went out

Note: this is a typical scenario based on situations common during floods. It is not the account of any real person.

Tom lives in a townhouse in the Wat Bang Khwang community near Tha Nam Non pier. In early October 2026 (B.E. 2569) the Chao Phraya River rose to a watch level, the municipality laid sandbags around the pier and water pooled in places. Worried about getting out to shop, Tom cooked a big pot of curry and plenty of rice for the family. That night the power in the lane went out for hours. The fridge stopped, the leftover curry sat on the stove overnight and the rice went cold in the cooker.

The next morning everyone ate the leftovers rather than waste them. Within a few hours Tom and his son felt sick, vomited, had cramps and then repeated diarrhoea. His mother, who had eaten only rice with an omelette, felt fine. Tom wondered whether the flood was to blame or the leftovers, and whether a kitchen that water had seeped into was still safe.

Food poisoning after a flood rarely has one cause. Power cuts, warm fridges, too little clean water for hands and dishes, and sewage residue in the kitchen all combine. This article explains each germ and how to make a kitchen safe again.

What did the news report about the Tha Nam Non and Wat Bang Khwang flood of 2026 (B.E. 2569)?

According to Thai PBS at 06:55 on 7 October 2026 (B.E. 2569), the Chao Phraya River at Tha Nam Non pier, Mueang Nonthaburi District, Nonthaburi reached the watch level of 1.80 to 2.30 metres (yellow flag). The municipality ran four pumps around the clock, laid sandbags around the pier, and water pooled at some points. The affected area included Tha Nam Non and the Wat Bang Khwang community.

Riverside neighbourhoods like this mix homes, restaurants and food stalls. When water pools or seeps in, food safety risks rise both at home and in shops, from storing ingredients to washing dishes and keeping food at safe temperatures.

Nationally, DDPM data as of 06:00 on 7 October 2026 (B.E. 2569), published by the Government Public Relations Department, recorded flooding in 27 provinces plus Bangkok, 123 districts and 984 subdistricts, with 1,154,875 households or more than 3.1 million people affected. We use only these reported facts. Tom's story is an illustration; we do not claim any food poisoning cases at Tha Nam Non.

Why is food poisoning more common after floods?

• Power cuts stop fridges, leaving chilled food at temperatures where bacteria multiply fast.
• Cooking in big batches to avoid going out, then leaving leftovers at room temperature for hours.
• Floodwater touching food and dishes: rice, vegetables, dry goods in bags and crockery may carry sewage germs.
• Too little clean water for washing hands, vegetables and dishes properly.
• Muddy kitchens: boards, counters and shelves that are not fully clean harbour germs.
• Donated meals and boxed food transported for hours in hot weather should be eaten promptly.
• Exhausted bodies may become sicker than usual when exposed.

Food poisoning after a flood: which germs cause it? Meet 12 culprits

Food poisoning germs fall into two broad types. Some produce toxins in the food, so symptoms start within hours. Others multiply in the gut, so symptoms appear later, from about half a day to several days.

1. Staphylococcus aureus

Lives on skin and in noses. If a cook does not wash hands or has a cut on the hand, it can get into food and produce toxin while the food sits at room temperature. Symptoms start fast, about 30 minutes to six hours: nausea, severe vomiting and cramps. The toxin is heat-stable, so reheating does not make the food safe.

2. Bacillus cereus

Classically linked to cooked rice, fried rice and starchy foods left to cool at room temperature. Its spores survive cooking, then germinate and form toxin as rice sits, causing vomiting within hours or diarrhoea later. A power cut that stops the rice cooker's warm setting is a direct risk.

3. Clostridium perfringens

Associated with large batches, such as big pots of curry, stews and mass-cooked donated meals that cool slowly. It causes cramps and diarrhoea about six to 24 hours later, usually without much vomiting or fever.

4. Salmonella

Comes with eggs, chicken, pork and undercooked food, or from using one board for raw and cooked items. It causes fever, cramps and diarrhoea about six hours to three days after eating, and can be severe in young children, older people and those with weak immunity.

5. Vibrio parahaemolyticus

Linked to raw or undercooked seafood and river animals such as shellfish, shrimp and fish. It causes cramps, diarrhoea, nausea and sometimes fever. Seafood spoils especially fast when fridges are down.

6. Campylobacter

Common in raw chicken and water contaminated by animal droppings. It causes fever, strong abdominal pain and diarrhoea, sometimes bloody, starting two to five days after eating, so people often do not connect it with the meal.

7. Disease-causing Escherichia coli

Some E. coli types cause watery diarrhoea; others cause bloody diarrhoea and can affect the kidneys, especially in children. Sources include vegetables washed in contaminated water, undercooked meat and unwashed hands. Floodwater passing through drains and septic tanks spreads these bacteria widely.

8. Norovirus

The leading viral cause of food poisoning. It spreads through food handled by a sick person, ice, fresh produce and raw shellfish, causing sudden vomiting and diarrhoea within about 12 to 48 hours, and then passes easily around a household via hands and surfaces.

9. Shigella

Spread by food prepared by someone who did not wash after the toilet, or produce rinsed in contaminated water. It causes stools with mucus and blood, straining and fever, and only a few bacteria are needed.

10. Hepatitis A virus

Not an instant food poisoning, but it spreads through food and water contaminated with stool. After an incubation of several weeks it causes fever, tiredness, nausea, dark urine and yellow skin and eyes. Vaccination, on a doctor's advice, helps prevent it.

11. Listeria monocytogenes

Can grow even in the fridge, in processed meats, ready-to-eat sausages, unpasteurised milk and chilled food kept too long. It usually causes flu-like fever and aches, but matters most for pregnant women, older people and those with weak immunity, who should see a doctor if they develop fever after eating risky foods.

12. Clostridium botulinum

Rare but important. Its toxin can form in sealed canned or fermented food that was processed incorrectly, such as home-canned bamboo shoots, or in dented, swollen or leaking cans. Symptoms begin with blurred or double vision, drooping eyelids, difficulty swallowing, slurred speech and weak limbs. These need hospital care immediately. Swollen or dented cans from a flood must always be thrown away.

Food poisoning after a flood: when should you see a doctor right away?

Most food poisoning improves within one or two days, but go to a doctor or hospital immediately if:

• Vomiting stops you keeping any fluids down
• There are signs of dehydration: very little dark urine, dry mouth, dizziness on standing, severe weakness or drowsiness
• Stools contain blood or mucus and blood, or are black
• There is high fever, shivering or severe, persistent abdominal pain
• Diarrhoea lasts more than two to three days without improving
• Blurred or double vision, drooping eyelids, trouble swallowing, slurred speech or weak limbs appear, which may point to botulinum toxin
• Skin or eyes turn yellow, or urine becomes dark like tea
• The person is a young child, an older adult, pregnant, or has chronic illness or weak immunity
• Several people at home or in the community fall ill after the same meal; tell local health officials as well

Tell the doctor about the flood, the power cut, what you ate and when. If suspect food remains, bag it separately in case officials want to test it. At home, take frequent sips of clean water and oral rehydration fluid as health workers advise. Do not buy anti-diarrhoea or other medicines without asking a doctor or pharmacist.

What food should you throw away after a flood and power cut?

The simplest rule public health agencies give is "When in doubt, throw it out." Contaminated or toxin-laden food can look, smell and taste normal.

• Anything that touched floodwater, including fresh produce, rice and dry goods in bags or cardboard, and bottled condiments with screw caps or stoppers that water can enter.
• Perishable fridge food after a power cut of more than about four hours, especially meat, seafood, milk, eggs, cooked dishes and cooked rice.
• Cooked food left at room temperature for more than two hours, or less on hot days.
• Dented, swollen, leaking or rusty cans, or cans with bulging lids.
• Home-fermented or home-sealed foods reached by floodwater or of uncertain preparation.
• Melted freezer ice and ice made from water of uncertain quality.
• Formula and baby food whose containers were flooded.

Following CDC guidance, undamaged commercially canned food can be kept if you wash, disinfect and dry the outside of the can before opening. Wooden boards, wooden utensils, teats and heavily scratched plastic containers that were flooded should be discarded because they cannot be cleaned thoroughly.

Where do food poisoning germs hide in a kitchen after the water recedes?

1. Chopping boards, knives and utensils that were flooded or used for raw and cooked food
2. Counters and prep tables with a thin film of mud
3. Fridges and freezers with meltwater or floodwater inside
4. Sinks and drains where sewage may back up
5. Dish racks, drainers and drawers that are still damp
6. Hand towels, tea towels and sponges, which breed germs when wet
7. Water tanks, containers and filters reached by floodwater
8. Fridge handles, taps and switches touched by everyone

How can you prevent food poisoning after a flood?

• Cook just enough for each meal while power cuts are possible.
• Cook thoroughly, especially meat, eggs and seafood, and eat food hot.
• Keep raw and cooked apart with separate boards and knives.
• Wash hands with soap before cooking and eating and after the toilet. Anyone with diarrhoea or vomiting should not cook for others until recovered.
• Use safe water (bottled or boiled) for drinking, washing produce, making ice and preparing formula.
• Keep the fridge closed during outages to hold the cold longer, and use a thermometer if you have one.
• Eat donated meals promptly within the time suggested, not at the next meal.
• Clean the kitchen before cooking again: detergent, rinse, then disinfect per the label.

Why is cleaning the kitchen yourself not quite enough?

Washing with clean water and detergent always comes first. But flooded kitchens have many hidden corners: under the sink, behind the fridge, cabinet feet and tile grout, where mud and sewage residue tend to stay. Some people mix products without knowing the fumes can be dangerous, or wipe disinfectant off before its label contact time. Riverside restaurants and food stalls reopening after a flood need to be sure prep areas, staff toilets and dishwashing points are truly clean. WHO and the CDC both advise cleaning flood-contaminated surfaces first and then disinfecting them, and a professional team can handle that second step efficiently.

How does WHD's disinfection spraying help kitchens and homes after the Nonthaburi flood of 2026 (B.E. 2569)?

World Health Disinfection (WHD) provides a disinfection spraying service by trained technicians who spray and/or ULV-fog, according to the service information. The disinfectant is CHEMGENE HLD4H, a medical-grade product from the United Kingdom containing Benzalkonium Chloride and Didecyldimethylammonium Chloride.

According to WHD's service and product information, it covers viruses, bacteria and fungi, and the listed organisms include norovirus and Salmonella, two major causes of food poisoning, with a claimed 99.99% efficacy and listed approvals or testing linked to the Department of Medical Sciences, Mahidol University, NHS England and EN 14476:2013+A2:2019. Other germs here, such as Staphylococcus, E. coli, Vibrio, Campylobacter, Shigella, Listeria and hepatitis A, belong to the bacteria and virus groups the product says it covers, but the website does not show organism-specific results; ask WHD if you need test data.

Be clear about the limits: spraying treats surfaces. It does not destroy toxins already in food and does not make contaminated food edible. Spore-forming bacteria such as Bacillus cereus and Clostridium are controlled mainly by scrubbing residue away and keeping food at safe temperatures. Risky food must be discarded, and kitchens must be washed before spraying.

The process:

1. Assessment: by phone or LINE, with photos of the home or shop and how high the water reached.
2. Mud removal and washing first: discard contaminated food, wash the kitchen and dishes.
3. Zoning and preparation: washed food, dishes and utensils are stored in closed cupboards; people and pets leave the zone.
4. Spraying: focusing on kitchens, counters, sinks, bathrooms and high-touch points.
5. Re-entry: the service information says to wait about 30 minutes before normal use. Follow the technicians' re-entry time, and rinse food-contact surfaces with clean water as they advise before cooking.

WHD is based in Bang Khae, Bangkok 10160, with no branch in Nonthaburi; jobs are arranged by phone and LINE. Customers receive a free CHEMGENE spray bottle and WELLGIENIC wet wipes under the current promotion, and a tax invoice is available, suiting both homes and restaurants. For lingering musty smells, ask about the residential ozone disinfection service.

10 reasons kitchens and restaurants should disinfect after a flood

1. The kitchen is where flood germs reach the body most directly, through food.
2. Norovirus and Salmonella are listed as covered on WHD's disinfection service page.
3. It reaches under sinks, behind fridges and into grout after washing.
4. It helps reduce repeat spread when someone at home has been vomiting.
5. Restaurants can reopen with more confidence and tell customers cleaning was systematic.
6. Technicians use protective equipment and clear zones.
7. It avoids the risks of mixing chemicals yourself.
8. The product information cites EN 14476 testing.
9. Tax invoices suit shops and businesses; see the WHD service page.
10. Families cook at home with more peace of mind, alongside safe food and water choices.

Before and after disinfection: a home kitchen near Wat Bang Khwang, 2026 (B.E. 2569) (example case)

Note: an illustrative example, not a customer review. Spraying does not treat anyone who is ill.

Safe kitchen checklist after the Tha Nam Non flood of 2026 (B.E. 2569)

• ☐ Discard food that touched floodwater and fridge food after long outages
• ☐ Discard dented, swollen or leaking cans and uncertain fermented food
• ☐ Discard flooded wooden boards, sponges and tea towels
• ☐ Wash fridge, sink, counters and shelves with detergent
• ☐ Rewash stored dishes; sanitise with heat or per the label
• ☐ Clean or replace water filters and tanks
• ☐ Use bottled or boiled water for drinking and cooking
• ☐ Disinfect surfaces after cleaning, or call professionals
• ☐ Cook per meal, cook thoroughly, eat hot
• ☐ Watch for red flags and see a doctor when needed

Frequently asked questions: food poisoning after a flood

What causes food poisoning after a flood?

Usually germs or toxins in food kept at unsafe temperatures during power cuts, food touched by floodwater, and dirty hands or dishes. Common culprits include Staphylococcus, Bacillus cereus, Salmonella and norovirus.

How long after eating does food poisoning start?

It depends on the germ: 30 minutes to six hours for some, one to three days for others, and weeks for hepatitis A.

Which food poisoning symptoms need a hospital?

Vomiting that stops all fluids, dehydration, bloody stools, high fever, severe pain, blurred vision, trouble swallowing or weak limbs. Go immediately.

How long can fridge food last in a power cut?

Following CDC guidance, discard perishable fridge food after more than about four hours without power. When in doubt, throw it out.

Is food left out overnight safe if I reheat it?

No. Toxins from Staphylococcus and Bacillus cereus survive heat, so reheating does not help.

Can I eat canned food that was in floodwater?

Undamaged factory cans can be kept if washed and disinfected outside before opening. Dented, swollen or leaking cans must go.

Does food poisoning go away on its own?

Most cases improve within one to two days, but drink enough fluids and see a doctor for red flags or if things do not improve.

After the kitchen is sprayed, can I eat food that was flooded?

No. Spraying treats surfaces and does not make contaminated food safe. Throw it away.

Is there a disinfection service near me in Nonthaburi?

WHD is in Bang Khae, Bangkok, with no Nonthaburi branch, but takes jobs by appointment on 065-556-6294 or LINE @whd268.

The water is down at Tha Nam Non, Nonthaburi in 2026 (B.E. 2569). Let WHD finish the clean for your kitchen and home.

Throw out risky food, wash the kitchen, then let WHD disinfect surfaces before you cook again.

Book Post-Flood Disinfection

Call 065-556-6294 | LINE @whd268

World Health Disinfection, Bang Khae, Bangkok 10160. Nonthaburi and upcountry jobs by appointment via phone and LINE.

Related services

• World Health Disinfection spraying service
• CHEMGENE HLD4H disinfectant
• Residential ozone disinfection for musty post-flood homes

References

• Thai PBS, Chao Phraya level at Tha Nam Non, Nonthaburi (7 Oct 2026): https://thaipbs.or.th/news/content/559256
• Government Public Relations Department, DDPM data as of 7 Oct 2026: https://www.prd.go.th/th/content/category/detail/id/33/iid/548715
• World Health Organization, Food safety fact sheet: https://www.who.int/news-room/fact-sheets/detail/food-safety
• CDC, Floods: https://www.cdc.gov/floods/
• Department of Disease Control, Thailand: https://ddc.moph.go.th/