What does FATTOM stand for? It stands for Food, Acidity, Time, Temperature, Oxygen and Moisture, the six conditions that let harmful bacteria grow in food. Food safety classes teach it so cooks and servers remember what to control in a kitchen.
The idea is simple. Bacteria need all six to multiply quickly. Take one away, by chilling, drying, adding acid or limiting time, and growth slows or stops. Many students write it as FAT TOM, which makes it easier to picture and recall.
Quick facts
Stands for
Food, Acidity, Time, Temperature, Oxygen, MoistureAlso written
FAT TOMType
Mnemonic acronymHow to say it
FAT tomTaught in
Food handler courses, culinary school, health classDanger zone
41°F to 135°F, where bacteria grow fastestRelated terms
What does FATTOM stand for, letter by letter?
| Letter | Condition | What bacteria need |
|---|---|---|
| F | Food | Nutrients, especially protein and carbohydrates |
| A | Acidity | Little or no acid; they grow best at a pH near neutral |
| T | Time | Enough hours in the danger zone to multiply |
| T | Temperature | Warmth, between 41°F and 135°F |
| O | Oxygen | Some need air, some grow without it |
| M | Moisture | Available water in the food |
Because it is a memory aid, the order of the letters is about easy recall, not importance. Every condition matters. You can find more study tricks like this one on the memory acronyms page.
Each FAT TOM condition in a real kitchen
Food. Meat, poultry, eggs, dairy, cooked rice and beans give bacteria plenty to feed on. Plain crackers and dry pasta give them very little.
Acidity. Most harmful bacteria grow best in foods with a pH between about 4.6 and 7.5. Pickles, vinegar dressings and citrus are too acidic for most of them, which is why pickling is an old preservation method. Read more about the scale on the pH page.
Time and temperature. These two work together. Food left in the danger zone for too long gives bacteria a chance to double again and again. Kitchens keep cold food at 41°F or below, hot food at 135°F or above, and limit how long anything sits in between.
Oxygen. Some bacteria need air. Others, such as the one that causes botulism, grow without it, in sealed jars, vacuum packs or the center of a large pot.
Moisture. Fresh, juicy foods hold water that bacteria can use. Drying, salting and adding sugar tie up that water, so jerky, dried fruit and jam keep longer.
FATTOM and TCS food
Foods that give bacteria most of the FAT TOM conditions are called TCS foods, short for time/temperature control for safety. Because their food value, low acid and moisture cannot easily be changed, the kitchen controls the two things it can: time and temperature.
Line cook's checklist: "Cooked rice: cool from 135°F to 70°F within 2 hours, then to 41°F within 4 more." Rice is moist, low in acid and full of starch, so cooling it fast is the step that keeps it safe.
Food codes and health inspectors build many rules on this idea, and safety plans such as HACCP use it to find the points where a dish could go wrong.
How to remember the FATTOM acronym
Picture a cat named Tom who is a bit chubby: Fat Tom. He stays healthy only when he has food, mild conditions, time, warmth, air and water. Take away one of those and he slows down. The image is silly, which is exactly why it sticks.
Some instructors add a quick tip: the two Ts sit side by side because they are partners. Time and temperature are the two controls a cook can change on every shift. To see how acronyms like this are built, read what is an acronym.
Fat Tom acronym in sentences
- "Our food handler test had three questions on FAT TOM."
- "Vinegar lowers the pH, so it takes the A out of FATTOM."
- "Dried beans are safe on the shelf because the M in FAT TOM is missing."
- "The soup sat out all afternoon, which gave bacteria time and temperature."
- "Which FATTOM condition does a refrigerator control? Temperature."
Questions people ask
What does FAT TOM stand for in food safety?
FAT TOM stands for food, acidity, time, temperature, oxygen and moisture. These are the conditions bacteria need to grow, so controlling them keeps food safe.
Which FATTOM conditions can a food worker control?
Time and temperature are the easiest to control in daily work. Cooks keep food out of the danger zone and track how long it sits there. Recipes and processing can also change acidity and moisture.
What is the temperature danger zone?
In US food codes, it is 41°F to 135°F. Bacteria grow fastest in this range, which is why kitchens keep cold food at or under 41°F and hot food at or over 135°F.
Is FATTOM an acronym or a mnemonic?
It is both. It is an acronym made from the first letters of six words, and its purpose is to help people remember them, which makes it a mnemonic.
How do you pronounce FATTOM?
Most people say it as "fat Tom," like a name. That is why it is often written as two words.