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Food Safety

Food Safety is the discipline of handling, preparing, and storing food so as to prevent foodborne illness. This article is a study guide for the two standard credentials — the Food Handler card and the Certified Food Protection Manager (CFPM) — and it grounds the rules in the federal framework that governs them. Because a large share of foodborne illness is viral, it connects directly to the Library's virology research: see Virology Antivenom Immunology and Aromatic Antimicrobials, Bacteriophages Endolysins and Biological Inhibitors, and, for Hepatitis A and the liver, Immunometabolism Thermogenerative Stimulants and Hepatic Resilience.

The federal framework

Food safety in the United States rests on a layered set of federal authorities. These are the "federal food-safety stuff" the certification exams test:

Federal Food, Drug, and Cosmetic Act (FD&C Act, 1938) — the foundational statute. It prohibits the adulteration and misbranding of food in interstate commerce and gives the Food and Drug Administration (FDA) its core authority.
FDA Food Code — a model code the FDA updates every few years (most recently the 2022 edition). It is not itself law; states and localities adopt it (often with amendments) as their retail food regulation. Nearly every rule below — the danger zone, cooking temperatures, cooling, the Certified Food Protection Manager requirement — comes from the Food Code.
Food Safety Modernization Act (FSMA, 2011) — the largest reform of U.S. food-safety law since 1938. It shifted the focus from responding to contamination to preventing it, and requires most food facilities to have a written, HACCP-based preventive-controls plan.
HACCP — Hazard Analysis and Critical Control Points — the systematic, preventive method at the center of modern food safety (see its own section below). Mandatory for juice, seafood, and USDA meat/poultry plants, and the backbone of FSMA.
USDA Food Safety and Inspection Service (FSIS) — regulates meat, poultry, and processed egg products (FDA regulates essentially everything else).
Certified Food Protection Manager (CFPM) — the Food Code requires at least one employee with managerial authority to hold a food-protection-manager certification from an ANSI-accredited program. The common exams are ServSafe (National Restaurant Association), the National Registry of Food Safety Professionals, Prometric, and 360training. A Food Handler card is the entry-level credential for line staff; the CFPM is the manager-level credential.

FAT TOM — the six conditions pathogens need

Pathogens multiply when six conditions are met. Control any of them and you slow or stop growth. The mnemonic is FAT TOM:

Food — pathogens need nutrients, especially protein-rich and carbohydrate-rich "time/temperature control for safety" (TCS) foods: meat, poultry, seafood, dairy, eggs, cooked rice and beans, cut melons, cut leafy greens, cut tomatoes, garlic-in-oil, sprouts, tofu.
Acidity — most pathogens prefer a near-neutral pH (6.0–7.5). This is why acidic pickling (pH ≤ 4.6) and fermentation preserve food; see Pickling and Preservation and Fermentation.
Time — given four or more hours in the danger zone, populations reach infectious levels.
Temperature — the Temperature Danger Zone (below).
Oxygen — some pathogens are aerobic, some anaerobic. Clostridium botulinum is anaerobic, which is why sealed low-acid jars are its hazard (see the lime/firming-agent warning in Pickling and Preservation).
Moisture — measured as water activity (aw). Pathogens generally need aw above 0.85; drying, salting, and sugaring preserve food by lowering it.

Temperature control

Temperature is the control most under a cook's direct command.

The danger zone

The Temperature Danger Zone under the FDA Food Code is 41 °F to 135 °F (5 °C to 57 °C). (Older materials say 40–140 °F; use your jurisdiction's number.) TCS food should spend as little time as possible in this range; the Food Code limit is four hours cumulative before the food must be discarded.

Safe minimum internal cooking temperatures

Measured with a calibrated, clean thermometer at the thickest part. Hold for the time the Food Code specifies:

165 °F (74 °C) — poultry; stuffed meats/poultry; stuffing; anything reheated for hot holding; dishes combining already-cooked and raw TCS items.
155 °F (68 °C) — ground meat (beef, pork), ground/flaked fish, mechanically tenderized meat, shell eggs held for service.
145 °F (63 °C) — whole cuts of beef, pork, lamb, veal (steaks, chops, roasts); fish; eggs cooked to order and served immediately. (A rest/dwell time applies to some roasts.)
135 °F (57 °C) — fruits, vegetables, grains, and legumes that will be hot-held.

Cooling, reheating, holding

Cooling (two-stage): from 135 °F to 70 °F within 2 hours, then 70 °F to 41 °F within 4 more hours — six hours total. If the first stage is missed, reheat and start over. Use shallow pans, ice baths, ice paddles, and portioning to cool fast.
Reheating for hot holding: to 165 °F within 2 hours.
Hot holding: at or above 135 °F. Cold holding: at or below 41 °F.
Thawing: in the refrigerator; under running water ≤ 70 °F; in the microwave if cooked immediately; or as part of the cooking process. Never thaw at room temperature.

The Big 6 pathogens (highly infectious, reportable)

The Food Code names pathogens so contagious that an infected handler must be excluded from the operation and the case reported to the regulatory authority. Note that two of the six are viruses:

Norovirus (virus) — the single most common cause of foodborne illness in the U.S. Spread fecal–oral, often by an ill handler touching ready-to-eat food; extremely low infectious dose; resists many sanitizers (needs higher chlorine concentrations). See Virology Antivenom Immunology and Aromatic Antimicrobials.
Hepatitis A (virus) — fecal–oral, long incubation, attacks the liver; associated with shellfish and infected food workers; a vaccine exists. Liver context: Immunometabolism Thermogenerative Stimulants and Hepatic Resilience.
Salmonella Typhi — typhoid fever.
Shiga toxin–producing Escherichia coli (STEC) — e.g. O157:H7; undercooked ground beef, raw produce.
Shigella spp. — fecal–oral, flies, infected handlers.
Nontyphoidal Salmonella — poultry, eggs, produce.

Beyond the Big 6, know Clostridium botulinum (anaerobic; canning/low-acid hazard), Clostridium perfringens (improperly cooled meats — the "cafeteria germ"), Bacillus cereus (reheated rice), Listeria monocytogenes (grows at refrigeration temperatures; deli, soft cheese), Staphylococcus aureus (toxin from hands), and Vibrio and Campylobacter.

Foodborne viruses — the virology connection

Viruses do not grow in food — they hitchhike on it and need only a tiny dose to infect. That makes them a handling and hygiene problem rather than a temperature problem, and it is why the single most powerful control against them is excluding sick employees and rigorous handwashing. Norovirus, Hepatitis A, rotavirus, and Hepatitis E are the principal foodborne viruses. For the biology — viral structure, immune response, and the aromatic antimicrobials that act on enveloped pathogens — see the Library's virology research: Virology Antivenom Immunology and Aromatic Antimicrobials and Bacteriophages Endolysins and Biological Inhibitors.

Personal hygiene and employee health

Handwashing — the single most important behavior. Wash for at least 20 seconds with soap and warm water: after using the restroom, before starting work, after handling raw meat, after touching the face/hair/body, after taking out trash, after eating or smoking, and after any task that could contaminate the hands.
No bare-hand contact with ready-to-eat (RTE) food — use gloves, tongs, deli paper, or utensils. Gloves are single-use and not a substitute for handwashing.
Exclude or restrict ill employees. A handler must be excluded for vomiting, diarrhea, jaundice, or a diagnosed "Big 6" illness, and reported. The "Big 5" reportable symptoms/illnesses to a manager are vomiting, diarrhea, jaundice, sore throat with fever, and lesions with pus.
Clean uniforms, hair restraints, trimmed nails, no jewelry (a plain band may be allowed), no eating/gum in prep areas.

Cross-contamination

Store raw animal foods below and away from ready-to-eat foods; within the cooler, store by final cook temperature — ready-to-eat on top, then 135 °F foods, 145 °F, 155 °F, and raw poultry (165 °F) on the bottom.
Use separate or color-coded cutting boards and utensils for raw proteins vs. produce; clean and sanitize between tasks.
Practice FIFO (First In, First Out) and date-mark RTE TCS food held more than 24 hours (discard by day 7 at 41 °F).

Allergens — the Big 9

Federal law requires labeling of the major allergens. The Big 9 are milk, eggs, fish, crustacean shellfish, tree nuts, peanuts, wheat, soybeans, and sesame — sesame was added by the FASTER Act of 2021, effective 2023. Prevent allergen cross-contact with clean hands, clean equipment, and clear communication between service and kitchen.

Cleaning and sanitizing

Cleaning removes soil; sanitizing reduces pathogens to safe levels — they are two steps.

Three-compartment sink: wash (detergent, ≥ 110 °F) → rinse (clean water) → sanitize → air dry (never towel dry).
Chemical sanitizer concentrations (test with strips): chlorine 50–100 ppm, quaternary ammonium per manufacturer (~200 ppm), iodine 12.5–25 ppm. Contact time and water temperature/pH matter.
Heat sanitizing: in a dish machine, a final rinse that reaches 171 °F at the surface (or 180 °F at the manifold), or immersion for 30 seconds at 171 °F.

HACCP — the seven principles

A written food-safety plan built on seven steps: (1) conduct a hazard analysis; (2) determine the critical control points (CCPs); (3) establish critical limits; (4) establish monitoring procedures; (5) establish corrective actions; (6) establish verification; (7) establish record-keeping. Under FSMA this preventive approach is required of most food facilities.

Receiving and storage

Inspect deliveries immediately; reject TCS food received above 41 °F (or the specified receiving temperature), damaged packaging, pest evidence, or off odors/colors.
Store dry goods cool and dry (50–70 °F, off the floor); label and date; keep chemicals stored away from and below food.

Study tips for the exam

Memorize the numbers cold: danger zone 41–135 °F, the cook temps (165 / 155 / 145 / 135), cooling (135→70 in 2h, 70→41 in 4h), reheat 165 in 2h, sanitizer 50–100 ppm chlorine.
Know FAT TOM and the Big 6 (and which two are viruses).
Know who regulates what: FDA (Food Code, most food), USDA-FSIS (meat/poultry/egg products), FSMA (prevention), HACCP (the method).
For the manager (CFPM) exam, expect questions on supervision, training, active managerial control, and the documentation HACCP/FSMA require.

Sources

U.S. Food and Drug Administration, FDA Food Code (2022 ed.). FDA Food Code
FDA, Food Safety Modernization Act (FSMA). FSMA
Centers for Disease Control and Prevention, Foodborne Illness and the Burden of Norovirus. CDC Norovirus
National Restaurant Association, ServSafe Manager (ANSI-accredited CFPM).
USDA Food Safety and Inspection Service, Safe Minimum Internal Temperatures. USDA FSIS
FASTER Act of 2021 (sesame as the 9th major allergen).

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