3.1 Foodborne Illness & FAT TOM
Key Takeaways
- FAT TOM names the six conditions pathogens need to grow: Food, Acidity, Temperature, Time, Oxygen, and Moisture.
- TCS (time/temperature control for safety) foods are moist, protein-rich, near-neutral foods such as meat, eggs, dairy, cooked rice, cut melon, and cut leafy greens.
- The Big 6 reportable pathogens are Norovirus, Hepatitis A, Salmonella Typhi, nontyphoidal Salmonella, Shigella, and Shiga toxin-producing E. coli (STEC).
- Highly susceptible populations - older adults, young children, pregnant women, and the immunocompromised - are exactly the residents most CDMs serve.
- A foodhandler diagnosed with a Big 6 illness must be excluded or restricted from work under the FDA Food Code.
Why This Domain Carries the Most Weight
Sanitation and Safety is the single largest domain on the CDM, CFPP exam at 24% of scored items. The reason is built into the credential itself: a Certified Dietary Manager is also a Certified Food Protection Professional (CFPP), and the people you feed - nursing-home residents, hospital patients, children - are the most likely to die from a foodborne illness. Master this chapter and you secure roughly a quarter of the exam.
What Is a Foodborne Illness?
A foodborne illness is a disease transmitted to people through food. An outbreak is two or more people who get the same illness after eating the same food, confirmed by a lab and health authority. Contaminants fall into four groups:
- Biological - bacteria, viruses, parasites, and fungi (the leading cause)
- Chemical - cleaners, sanitizers, pesticides, toxic metals from acidic food in the wrong container
- Physical - glass, bone, metal shavings, packaging
- Allergens - the cross-contact transfer of an allergen to a food that should not contain it
FAT TOM: The Six Conditions for Growth
Bacteria need six conditions to multiply. The mnemonic FAT TOM captures them, and a manager controls illness by removing any one factor.
| Factor | What it means | Control lever |
|---|---|---|
| Food | Protein-rich, moist foods (meat, eggs, dairy) | Limit nutrient supply |
| Acidity | Pathogens grow best at pH 4.6 to 7.5 | Acidify (pickling lowers pH) |
| Temperature | Fastest growth in the 41 to 135 degrees F danger zone | Hold hot or cold |
| Time | Bacteria can double every 20 minutes | 4-hour cumulative limit |
| Oxygen | Most are facultative (grow with or without it) | Hard to control directly |
| Moisture | Water activity (aw) above 0.85 supports growth | Dry, salt, or sugar-cure |
TCS Foods
Foods that hit several FAT TOM marks are called TCS (time/temperature control for safety) foods - formerly "potentially hazardous foods." Examples: cooked meat and poultry, dairy, eggs, cooked rice and pasta, sprouts, cut tomatoes, cut leafy greens, cut melons, and garlic-in-oil mixtures. These are the foods your safety procedures protect.
Major Pathogens You Must Know
The exam expects you to match a pathogen to its common source and its main control.
| Pathogen | Type | Common source | Key control |
|---|---|---|---|
| Salmonella | Bacteria | Poultry, eggs, produce | Cook poultry to 165 degrees F |
| Listeria monocytogenes | Bacteria | Deli meats, soft cheese, raw produce | Grows at fridge temps; discard old RTE food |
| Norovirus | Virus | RTE food touched by an ill worker | Exclude sick staff; handwashing |
| Shiga toxin E. coli (STEC) | Bacteria | Ground beef, raw produce | Cook ground meat to 155 degrees F |
| Clostridium perfringens | Bacteria | Large batches of meat, stew, gravy held warm | Cool and reheat properly |
Listeria is dangerous because it keeps growing at refrigerator temperatures and is deadly to pregnant women and the elderly. C. perfringens is the classic "buffet" or "cafeteria" germ that thrives when big batches cool too slowly - a direct foodservice risk.
High-Risk (Highly Susceptible) Populations
The FDA Food Code names highly susceptible populations: older adults, preschool-age children, pregnant women, and people who are immunocompromised. These are precisely the residents and patients CDMs serve, which is why rules such as no raw or undercooked eggs and no raw sprouts are stricter in healthcare settings.
The Big 6 Reportable Pathogens
The Big 6 are highly infectious illnesses that a sick employee must report to the person in charge (PIC), who must then exclude or restrict that worker:
- Norovirus
- Hepatitis A (virus)
- Salmonella Typhi (typhoid fever)
- Nontyphoidal Salmonella
- Shigella spp.
- Shiga toxin-producing E. coli (STEC)
Two are viruses (Norovirus, Hepatitis A); the rest are bacteria. Exclude means keep the worker entirely out; restrict means keep them away from exposed food and clean equipment.
A cook prepares a large pan of beef stew, holds it at room temperature on the counter for several hours, and the stew later sickens diners. Which FAT TOM factors were MOST directly abused?
A dietary aide is diagnosed with Hepatitis A. Under the FDA Food Code, what must the person in charge do?
Why is Listeria monocytogenes an especially serious concern in a long-term-care kitchen?