Highly Susceptible Populations in Food Safety: Foods, Rules, Enforcement

In food safety regulation, a highly susceptible population is a group of people whose bodies are less able to fight off foodborne pathogens and who receive their meals in an institutional setting. The FDA Food Code uses the term to trigger stricter rules for facilities like nursing homes, hospitals, assisted living residences, and child care centers.¹ Those rules prohibit certain foods outright, require pasteurized substitutes in others, and raise the bar for excluding sick employees from the kitchen. A pathogen that would give a healthy adult a rough day can hospitalize or kill someone in one of these groups, and the regulations reflect that gap.

Who Qualifies

The Food Code definition has two parts, and both must be present. The person must fall into a vulnerable category, and they must be receiving food at a facility that provides custodial care, health care, assisted living, or nutritional and socialization services.¹ A preschooler eating with their parents at a diner does not turn that diner into an HSP facility.

The three vulnerable categories are:

Preschool-age children, whose immune systems have not fully developed. Juice-specific protections extend further, covering children age nine and younger who receive food in a school, day care, or similar custodial setting.
Older adults, whose defenses have weakened with age and who are more likely to be hospitalized or die from a foodborne illness.²
Immunocompromised individuals, including people with cancer, HIV/AIDS, or diabetes, and people taking chemotherapy or anti-rejection drugs after an organ transplant.³

Qualifying facilities include child and adult day care centers, kidney dialysis centers, hospitals, nursing homes, and senior centers.¹

A Note on Pregnant Women

Pregnancy raises the risk of foodborne illness, and the CDC advises pregnant women to avoid unpasteurized soft cheeses, unheated deli meats, raw sprouts, and undercooked animal products.⁴ But the Food Code’s HSP definition does not list pregnant women as a category, because HSP rules govern facility kitchens rather than individual diets.¹ The regulatory framework addresses their risk through consumer guidance instead.

Why These Groups Are More Vulnerable

The categories are not arbitrary. Each reflects a real biological gap in the body’s ability to neutralize pathogens.

Young children are still building the immune memory that comes from repeated exposures over years. A preschooler meeting Salmonella or E. coli for the first time has fewer tools to mount a rapid defense, and a smaller body mass means the same dose of a toxin hits harder.

Older adults face a cluster of changes that reinforce each other. The immune system weakens, the gastrointestinal tract slows and holds food longer (giving bacteria more time to multiply), and the liver and kidneys clear toxins less efficiently.² Stomach acid production often falls with age, and proton pump inhibitors prescribed for reflux suppress it further. Research links PPI use in older adults to higher rates of infection from Campylobacter, Salmonella, and Clostridium difficile.

Immunocompromised individuals are, in some cases, suppressed deliberately. Anti-rejection drugs after an organ transplant keep the body from attacking the new organ but also leave it unable to fight off ordinary bacteria.³ Chemotherapy destroys cancer cells and white blood cells alike. HIV/AIDS and diabetes impair immune function through different mechanisms but with a similar outcome: a bacterium a healthy person would never notice can cause a life-threatening infection.

Foods That Cannot Be Served

Section 3-801.11 of the FDA Food Code sets out the specific restrictions. A facility serving an HSP cannot use a consumer advisory to serve items that would otherwise require one. The prohibitions are absolute.⁵

Raw and Undercooked Animal Foods

No raw animal foods in ready-to-eat form. That covers raw fish, raw-marinated fish, raw shellfish, steak tartare, rare meat, lightly cooked fish, and soft-cooked eggs made from raw shell eggs.⁵ These items are the most common vehicles for Salmonella, Listeria monocytogenes, and parasites.

Eggs

Pasteurized eggs or egg products must be substituted for raw shell eggs in any recipe where the egg will not be thoroughly cooked. The Food Code names Caesar salad dressing, hollandaise and béarnaise sauce, mayonnaise, meringue, eggnog, ice cream, and egg-fortified beverages.¹ The substitution also applies whenever more than one egg is broken and combined, unless the eggs are combined immediately before cooking for a single person’s serving and cooked all the way through, as in a scrambled egg or omelet.

Raw Seed Sprouts

Sprouts cannot be served in any form.⁵ The warm, humid conditions sprouts need to germinate are ideal for bacterial growth, pathogens can lodge inside the plant tissue during germination, and sprouts are typically eaten without any cooking step that would kill bacteria.

Juice

For juice, the covered population expands to include children age nine and younger receiving food in a school, day care, or similar custodial setting.¹ Prepackaged juice bearing a warning that it has not been processed to reduce pathogens cannot be served. Juice prepared on-site must be processed under a HACCP plan that achieves at least a 5-log pathogen reduction (99.999% of the targeted bacteria destroyed).⁶

Soft Cheeses and Deli Meats

The Section 3-801.11 list does not name these, but federal guidance treats them as high-risk for Listeria in vulnerable individuals. The CDC recommends heating deli meats and hot dogs to 165°F before serving them to anyone with a weakened immune system.⁷ Facilities serving HSP groups typically handle unpasteurized soft cheeses and cold deli meats with the same caution as the items formally prohibited.

Stricter Employee Illness Rules

The Food Code applies a lower threshold for excluding sick workers when the customers are highly susceptible. In any food establishment, an employee with vomiting, diarrhea, jaundice, or a Hepatitis A or Typhoid diagnosis must be excluded. In an HSP facility, exclusion also applies to asymptomatic employees diagnosed with Norovirus, Shigella, or Shiga toxin-producing E. coli, situations where an ordinary restaurant would only restrict duties.⁵ The same stricter treatment applies to employees with a sore throat and fever, and HSP facilities must restrict employees who have merely been exposed to a foodborne pathogen even without a confirmed diagnosis.

A single asymptomatic carrier in a nursing home or hospital kitchen can infect dozens of people whose bodies cannot mount an effective defense, and the rules are calibrated to that reality.

How the Rules Are Enforced

The FDA Food Code is a model code, not federal law. The FDA publishes it as a science-based template, and state, local, and tribal governments adopt it into their own enforceable regulations.⁸ Penalties for HSP violations therefore vary by jurisdiction, ranging from administrative fines to progressive enforcement that escalates to permit suspension, with license revocation or criminal prosecution possible where serious negligence leads to an outbreak.

Health departments inspect facilities serving vulnerable populations for the prohibited items listed above, verify egg substitution practices, check juice labeling, and review employee health policies. Many jurisdictions inspect high-risk facilities more often than ordinary restaurants.

If You Cook for Someone in a Highly Susceptible Group at Home

The Food Code covers institutional kitchens, but the biology behind it does not stop at the facility door. If you prepare meals for a young child, an older adult, or someone whose immune system is compromised, the same principles apply.

Buy only pasteurized milk and dairy. Bag raw meat, poultry, and seafood separately at the store so juices do not drip. Skip dented, cracked, or bulging cans. Keep the refrigerator at 40°F or below and the freezer at 0°F or below, verified with an appliance thermometer, and refrigerate perishables within two hours (one hour above 90°F). Thaw in the refrigerator, in cold water, or in the microwave, never on the counter.⁹

Keep raw proteins separated from ready-to-eat foods at every stage. Never place cooked food on a plate that held raw meat without washing it in hot soapy water first. Sanitize countertops and cutting boards with one tablespoon of unscented liquid chlorine bleach per gallon of water after preparing raw meat.⁹

Use a food thermometer every time. Safe minimum internal temperatures:

Poultry of all types: 165°F
Ground meat and sausage: 160°F
Egg dishes: 160°F, or cook until yolk and white are firm
Steaks, roasts, and chops (beef, pork, lamb): 145°F with a three-minute rest
Deli meats and hot dogs: reheat to 165°F before serving to anyone with a weakened immune system

¹⁰ These numbers apply to any cook, but they are non-negotiable when feeding a highly susceptible person. A medium-rare steak or a runny yolk is a calculated risk for a healthy adult. For someone whose immune system cannot cover the difference, it is not.

1
U.S. Food and Drug Administration. FDA Food Code 2022 Full Document
2
FoodSafety.gov. People at Risk: Older Adults
3
U.S. Food and Drug Administration. Food Safety for Older Adults and People with Cancer, Diabetes, HIV/AIDS, Organ Transplants, and Autoimmune Diseases
4
Centers for Disease Control and Prevention. Safer Food Choices for Pregnant Women
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U.S. Food and Drug Administration. FDA Food Code 2022
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U.S. Food and Drug Administration. Juice HACCP Hazards and Controls Guidance First Edition
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Centers for Disease Control and Prevention. Safer Food Choices for People With Weakened Immune Systems
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U.S. Food and Drug Administration. FDA Food Code
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USDA Food Safety and Inspection Service. At-Risk Populations: Food Safety Booklet
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FoodSafety.gov. Cook to a Safe Minimum Internal Temperature