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Basic Knowledge of Food Poisoning

Food and Beverage Manufacturing · 飲食料品製造業 · Written by Tokutei Pass based on the official study texts; not copied verbatim.

Characteristics of Food Poisoning and the Three Prevention Principles

Food poisoning is a health hazard causing diarrhea, vomiting, and other symptoms after eating food contaminated with harmful bacteria, viruses, or toxins. The time from eating until symptoms appear is called the incubation period, meaning the most recent meal is not always the cause.

Unlike spoilage, even when food poisoning bacteria or viruses multiply, the taste, smell, and appearance of food often do not change, so safety cannot be judged by human senses alone. When three conditions—nutrients, moisture, and temperature—are met, bacteria divide and multiply exponentially.

The three principles of prevention are: Do not contaminate (つけない), Do not let multiply (増やさない), and Destroy (やっつける). Prevent secondary contamination via hands or cutting boards and fecal-oral infection, and suppress bacterial growth by drying, adding salt or sugar to reduce free water, or adding vinegar to lower the pH.

When multiple people who ate the same meal develop vomiting or diarrhea and food poisoning is suspected, report immediately to the person in charge. Follow instructions from the public health center, and keep leftover food and production records without discarding them to cooperate with the investigation.

Key points


  • The three principles of food poisoning prevention are: Do not contaminate, Do not let multiply, and Destroy.

  • The three conditions for bacterial growth are nutrients, moisture, and temperature; safety cannot be judged by taste or smell.

  • Secondary contamination is the transfer of bacteria or viruses from contaminated raw ingredients to clean food via hands or utensils.
WordMeaning
food poisoning
incubation period
secondary contamination (cross-contamination)
fecal-oral infection
water activity (available free water)

Temperature Control and Standards for Heating, Cooling, and Thawing

The temperature range of about 10°C to 60°C where bacteria multiply easily is called the temperature danger zone. Because workplace room temperature falls in this zone, never leave food at room temperature even between processing steps; store it refrigerated (10°C or below). Hot holding must be kept at 65°C or above.

Refrigeration and freezing suppress bacterial growth, but most bacteria survive and start multiplying again once the temperature rises. Thaw frozen meat and fish inside a refrigerator or sealed under running water to prevent secondary contamination from nutrient-rich red liquid (drip).

To destroy general food poisoning bacteria, heat food until the core temperature reaches 75°C for at least 1 minute. Because bacteria penetrate deep inside minced meat products, measure the center with a core thermometer that has been washed and disinfected with alcohol before and after use.

Wash raw vegetables with potable running water, sanitize with sodium hypochlorite, rinse thoroughly, and keep at 10°C or below. Make ice using potable water, regularly wash and sanitize the ice machine and scoop, and never leave the scoop inside the ice bin.

Key points


  • The temperature danger zone is about 10°C–60°C; keep hot holding at 65°C or above and refrigeration at 10°C or below.

  • The standard heating condition for general food poisoning bacteria is a core temperature of 75°C for 1 minute or longer.

  • Always wash and disinfect the probe of a core thermometer with alcohol before and after each use.

  • Thaw frozen food in a refrigerator or sealed under running water to prevent contamination from drip.
WordMeaning
temperature danger zone (10°C–60°C)
core thermometer
hot holding (65°C or above)
thawing (defrosting)
sodium hypochlorite (chlorine sanitizer)

Infection-Type Bacterial Food Poisoning

Bacterial food poisoning occurs frequently in hot and humid summers. The type in which bacteria ingested with food multiply inside the human intestine to cause illness is called infection-type (感染型) food poisoning.

Enterohemorrhagic E. coli (such as O157 and O111) is caused by undercooked beef or secondarily contaminated raw vegetables, lightly pickled vegetables, and well water; even a small amount of bacteria can cause severe illness due to Verotoxin. It is destroyed by heating at 75°C for 1 minute or longer.

Campylobacter is common in chicken, prefers low-oxygen environments, and causes illness in small numbers, but is weak against drying and heat. Salmonella is common in chicken eggs and poultry; after cracking eggs, do not leave them standing and heat them thoroughly. Both have an incubation period of half a day to several days.

Vibrio parahaemolyticus is a salt-loving bacterium on seafood; prevent it by washing thoroughly with fresh water, keeping cold, and heating. Listeria (causing severe illness in pregnant women and the elderly via soft cheese, cured ham, etc.) and Yersinia in pork can grow even in refrigerators at 0–4°C.

Key points


  • Representative infection-type bacteria include Enterohemorrhagic E. coli (O157), Campylobacter, Salmonella, and Vibrio parahaemolyticus.

  • O157 and Campylobacter can cause illness even in small numbers, but thorough heating to the core prevents them.

  • Vibrio parahaemolyticus is weak against fresh water, so washing seafood thoroughly with potable fresh water is effective.

  • Listeria and Yersinia enterocolitica can slowly multiply even at low temperatures inside a refrigerator.
WordMeaning
infection-type (bacteria multiply in the intestine)
enterohemorrhagic Escherichia coli (O157, etc.)
Vibrio parahaemolyticus (halophilic bacteria on seafood)
egg breaking (cracking eggs)

Toxin-Type Bacteria and Spore-Forming Bacteria

Illness caused by eating toxins produced by bacteria inside food is called toxin-type (毒素型) food poisoning. Staphylococcus aureus lives in hand wounds and produces a heat-resistant toxin (enterotoxin) in food that is not destroyed even by heating at 100°C.

Clostridium perfringens (Welchii), Clostridium botulinum, and Bacillus cereus form hard shell-like spores (芽胞). Spores withstand 100°C heating and drying; when cooked food cools slowly into the temperature danger zone, the spores germinate and multiply rapidly.

Clostridium perfringens and Clostridium botulinum are anaerobic bacteria that dislike oxygen. Large-batch dishes like curry or stew must be divided into small portions and cooled rapidly to prevent Clostridium perfringens. Bacillus cereus lives in soil and produces a heat-resistant vomiting toxin in rice and beans left at room temperature.

Clostridium botulinum produces a potent neurotoxin in canned or vacuum-packed foods. Retort pouches and canned foods undergo pressurized heat sterilization above 100°C to kill spores. If a container is abnormally swollen, never taste or ship it—report it immediately.

Key points


  • Staphylococcus aureus enterotoxin and Bacillus cereus vomiting toxin are heat-resistant and are not destroyed by reheating.

  • Clostridium perfringens, Clostridium botulinum, and Bacillus cereus form heat-resistant spores.

  • Divide large-batch cooked dishes like curry into small portions and cool them rapidly to prevent Clostridium perfringens growth.

  • Swollen canned or vacuum-packed foods may contain Clostridium botulinum toxin; never taste them and report immediately.
WordMeaning
toxin-type (toxins produced in food)
Staphylococcus aureus
bacterial spore (heat-resistant structure)
anaerobic bacteria (grow without oxygen)
pressurized heat sterilization (above 100°C)

Viral Food Poisoning (Norovirus and Hepatitis E)

Unlike bacteria, viruses do not multiply inside food; they multiply inside the human intestine. Norovirus, which peaks in winter, is caused by contaminated bivalve shellfish or secondary contamination from infected handlers' hands, and is highly infectious even in tiny amounts.

Because Norovirus continues to be shed in stool for one to several weeks even after symptoms subside, thorough handwashing is essential. Heat bivalve shellfish that may be contaminated to a core temperature of 85–90°C for at least 90 seconds.

Alcohol is less effective against Norovirus, so disinfect using sodium hypochlorite or heat at 85°C or above for at least 1 minute. When cleaning up vomit, wear disposable gloves and a mask, wipe it up, and disinfect with sodium hypochlorite.

In addition, pork meat, pork liver, and wild game meat (gibier such as wild boar and deer) may carry Hepatitis E virus, parasites, or bacteria. Never serve them raw; always heat them thoroughly to the core.

Key points


  • Viruses do not multiply in food but multiply in the human intestine; Norovirus is most common in winter.

  • The heating standard for bivalve shellfish against Norovirus is a core temperature of 85–90°C for 90 seconds or longer.

  • Use sodium hypochlorite or heating at 85°C or above for at least 1 minute to disinfect Norovirus.

  • Heat pork, pork liver, and wild game meat thoroughly to the core to prevent Hepatitis E virus and parasites.
WordMeaning
bivalve shellfish (oysters, scallops, clams, etc.)
infectivity (infectiousness)
vomit (vomitus)
wild birds and beasts (wild game meat / gibier)

Parasites, Natural Toxins, and Chemical Food Poisoning

Anisakis parasites in seafood are prevented by freezing at −20°C or below for at least 24 hours or by heating thoroughly. Kudoa parasites in olive flounder (Hirame) cause temporary diarrhea and vomiting a few hours after being eaten raw.

Among natural toxins, pufferfish poison (tetrodotoxin) and shellfish toxins in scallops or clams are not destroyed by heat; pufferfish must be prepared only by licensed specialists, and shellfish under shipping restrictions must not be used. Remove potato sprouts and green parts deeply from the base, and never use unknown mushrooms or wild plants.

Mycotoxins (mold toxins) produced by mold on grains and nuts are also heat-resistant and hard to break down by cooking, so proper storage to prevent mold growth is essential.

In chemical food poisoning, leaving red-fleshed fish (mackerel, tuna, sardines) at room temperature allows bacteria to convert histidine into heat-stable histamine, so strict cold storage is required. Store detergents and sanitizers in a dedicated area separate from food, and clearly label all containers to prevent accidental mixing.

Key points


  • Anisakis is killed by freezing at −20°C or below for at least 24 hours or by thorough heating.

  • Pufferfish toxin (tetrodotoxin), shellfish toxins, mycotoxins, and histamine are not broken down by heating.

  • Keep red-fleshed fish at low temperatures at all times to prevent histamine formation.

  • Store detergents and sanitizers in a dedicated place separate from food and always label their containers.
WordMeaning
parasite
natural toxin (pufferfish, potato sprouts, toxic mushrooms, etc.)
shellfish toxin (accumulated in bivalves)
red-fleshed fish (mackerel, tuna, sardines, etc.)
chemical food poisoning

Official references