FAT TOM

FAT TOM is a food-safety mnemonic used to remember six factors that can influence the growth of foodborne microorganisms: Food, Acidity, Time, Temperature, Oxygen and Moisture. It helps food handlers identify conditions that may allow microorganisms to grow, but it is a teaching aid rather than a complete food-safety assessment.

The six factors

• Food: nutrients in a food can support microbial growth.
• Acidity: pH influences which organisms can grow and how quickly.
• Time: microorganisms need time to multiply when conditions are suitable.
• Temperature: growth rates change with temperature; controlling hot and cold holding is essential.
• Oxygen: some organisms require oxygen, while others can grow without it.
• Moisture: available water supports microbial growth; water activity is more precise than total moisture content.

How kitchens use FAT TOM

Food handlers can use the mnemonic to understand why cooked rice, meat, dairy-based sauces and other moist foods need appropriate time-temperature control. It also reinforces the importance of acidity, formulation, packaging and storage conditions.

Chef’s safety note: Not all pathogens require all six conditions. Some grow without oxygen, and some survive conditions that prevent growth. Use FAT TOM as a reminder of risk factors, not as a substitute for a food-safety plan or validated controls.

Key distinction: FAT TOM summarizes factors affecting microbial growth; it does not identify a single critical limit or guarantee that a food is safe.