Foodborne Disease

Control and Prevention

Food Safety Oversight

Food quality and the systems used to prevent foodborne illnesses are mainly overseen by two federal agencies: the USDA and the FDA. The USDA regulates about 20% of the U.S. food supply including meat, poultry, and processed egg products. The FDA regulates the remaining foods including seafood, dairy, fruits, vegetables, multi-ingredient processed foods, and bottled drinking water.

The FDA's Food Code provides evidence-based best practices for food handling safety in the retail and food service industries. This includes restaurants, grocery stores, and some congregate settings such as skilled nursing facilities. Many states and jurisdictions have used the Food Code as a model to develop their own food regulations and codes. The food service codes for each state in the U.S. can be found on the FDA’s website.

Fruits and vegetables are now the most common sources of bacterial infections in the United States. Bacteria such as Salmonella, E. coli, and Listeria and the parasite Cyclospora are usually spread through contaminated produce, meat, seafood, or dairy products. In many cases contamination is only on the surface of these foods and can be removed through proper handling and washing. However, when contamination occurs in processed foods like deli meats, peanut butter, cheese, and ice cream, washing cannot remove the pathogens, and preventing exposure is not possible. Fortunately, this type of contamination is relatively rare.

When contaminated food is sold in stores or used in large-scale food preparation, it can lead to outbreaks of foodborne illnesses involving hundreds of people across multiple states. Detecting these outbreaks requires coordination between clinicians and state and local health departments. In multi-state outbreaks, the CDC interviews patients about what they ate and performs laboratory tests on both patient and food samples. This helps to identify the pathogen and trace it back to its food source. Depending on the food product, either the FDA or USDA will issue a recall of all contaminated products. Large-scale investigations may last for weeks before the source is identified.

Recommendations for All Workers

Handwashing

The most effective way to prevent the spread of foodborne diseases to others is by following hand hygiene best practices.

Always wash hands thoroughly for at least 20 seconds with soap and tepid water before and after handling food and especially when:

Handling livestock or other animals or their feed.
Working with soil when planting or tending crops or harvesting fruit.
Handling produce for shipment or resale.
Touching meat, seafood, or dairy products during production or resale.
Changing diapers or having close contact with infants, toddlers, and preschoolers in childcare settings.
Helping patients in hospitals or skilled nursing facilities, especially those who are vomiting or have diarrhea.
Using the restroom.

Meal Preparation

Use food hygiene best practices during meal preparation and cooking phases when serving food for consumption.

Wash produce thoroughly, especially when it will be served raw.
Use separate cutting boards to prepare raw meat or seafood and raw produce to prevent cross-contamination.
Wash cutting boards and countertops thoroughly where raw meat and seafood have been handled.
Use a food thermometer to measure internal temperatures of meats, seafoods, eggs, and leftovers to ensure that they meet the safe minimum temperatures provided by the USDA to prevent foodborne illness.

In addition, raw foods should be kept chilled prior to cooking or serving and leftover cooked foods should be refrigerated or frozen as soon as possible; do not leave perishable food sitting out at room temperature because bacteria grow rapidly at temperatures between 40▫ and 140^▫F, a range of temperatures the USDA calls the “Danger Zone”.

Avoid eating undercooked (meat, seafood, eggs) or raw animal products (raw milk, cheese, oysters) to reduce the likelihood of foodborne illness. Milk and fruit juices should be pasteurized for safety.

Water consumption

Do not drink or use ice made from untreated water sources (lakes, rivers, streams, rainwater, snowmelt, etc.). If this cannot be avoided:

Boil water for three minutes and let cool before drinking.
Use multi-barrier systems (multiple filters, filters and chemicals, etc.) or other methods proven to remove foodborne pathogens from water. Neither iodine tablets nor charcoal filters alone can kill or remove all foodborne pathogens from contaminated water.

OSHA requires that outlets for nonpotable water be labeled unsafe and not to used for drinking, washing of the person, cooking, washing of cooking or eating utensils, washing of food preparation or processing premises, or personal service rooms, or for washing of clothes [see §§ 1910.41(b)(2)(i), 1926.51(b), 1915.88(c), 1928.110(c)(4)(i)].

Overseas Workers

Although tap water is considered safe to drink in many countries, it is not safe in most of the world, so it is best to drink only bottled water if you are unsure. Drinking tap water in countries where water is treated and considered safe may impact health due to different chemical impurities, mineral content, and microbiota (microscopic organisms living in a particular habitat).

In many parts of the world, it is best to use bottled water for drinking, gargling, and brushing teeth. Do not use ice or eat any leafy vegetables. Only eat fruits and vegetables that can be peeled prior to eating.

OSHA’s authority is limited to United States and certain territories and jurisdictions under federal authority. When working for a U.S. company overseas, safety rules and regulations of that country and jurisdiction apply.

For more information about prevention of foodborne illness while traveling for work, see CDC’s Travelers’ Health webpage.

Laboratory Workers

Workers who culture foodborne bacteria, viruses, prions and microscopic parasites must follow guidance for barrier protection and to prevent accidental ingestion of these pathogens. According to the CDC’s Biosafety in Microbiological and Biomedical Laboratories – 6th Edition (BMBL6), Biosafety Level 2 (BSL-2) practices, equipment, and containment facilities should be used when handling foodborne organisms and Animal BSL-2 (ABSL-2) used for experimentally or naturally-infected animal models.

The likelihood of acquiring foodborne infections in the laboratory increases with the amount of agent that is cultured among other factors. For example, a lab worker using a large bioreactor to prepare Clostridium botulinum to extract toxins for medical use is at a higher risk of infection than a medical technician using culture plates in a hospital (assuming that all the necessary safety controls are in place).

In order to ensure that adequate biosafety controls are in place, a laboratory risk assessment should be performed and any additional protections implemented to prevent ingestion or inhalation should be added as determined by the assessment.

Foodborne bacteria

At a minimum, a full-length, long-sleeved lab gown, disposable latex or nitrile gloves, and a face shield or splash guard should be used to prevent accidental ingestion of pathogens on culture medium. Other laboratory equipment and practices should include:

Use sinks with foot pedals or else use dedicated “clean” and “dirty” sinks.
All tasks that generate aerosols (passaging, pipetting, vortexing, centrifuging, etc.) should be performed in a biosafety cabinet (BSC).
Care must be taken to disinfect BSC interiors, all benchtops, sinks and other surfaces and equipment that may have been contaminated with foodborne bacteria.

Foodborne viruses

Like foodborne bacteria, handling rotavirus and norovirus in the laboratory require BSL-2 practices, equipment, and containment facilities with special precautions taken when aerosol-generating procedures are used because some foodborne viruses (rotavirus, norovirus, poliovirus) can also be transmitted via inhalation of airborne droplets.

HAV and poliovirus have additional precautions and requirements. Animal models infected with HAV pose the highest risk of exposure and infection to laboratory and veterinary workers and are usually associated with animal handling and contact with feces. There is a vaccine against HAV and veterinary staff and workers in laboratories where HAV is handled should consider vaccination.

Working with poliovirus in the United States requires stringent protocols since it has been eliminated in the United States (and much of the world). Institutions may require that laboratory workers be vaccinated against polio prior to beginning work with the virus and laboratories must earn special certification by the CDC’s U.S. National Authority for Containment of Poliovirus (U.S. NAC).

Foodborne parasites

Nematode (Trichinella and Ascaris) and cestode (Taenia species) worms pose little risk of laboratory-acquired infections although their eggs may be very infectious and could possibly be ingested. BSL-2 practices, equipment, and facilities should be used when handling these parasites and it is recommended that special care be taken to thoroughly disinfect surfaces that may be contaminated with parasite eggs. Ascaris eggs may survive in the environment long after exposure to disinfectants and the CDC recommends their deactivation with boiling water (60° C) for at least 15 minutes.

Likewise, the single-celled parasites Giardia, Toxoplasma, Cryptosporidium, and Cyclospora should be handled using BSL-2 practices, equipment, and facilities. Cryptosporidium and Cyclospora are not killed using general disinfection procedures with diluted 10% bleach. Instead, hydrogen peroxide should be applied for at least 30 minutes to kill these organisms.

Treatment

Many foodborne diseases are self-limiting, meaning that they go away on their own. Common foodborne strains of Salmonella, Staphylococcus, and Shigella are often cleared by the immune system within a week. Viral infections such as norovirus may clear more rapidly, usually within 3 days.

Fluid replacement and rest are the most effective treatment for diarrhea from foodborne illnesses. Anti-diarrheal medications should be avoided since they prevent the body from clearing the infection. Long-lasting infections or those causing severe symptoms such as dysentery are treated with antibiotics.

Some strains of foodborne bacteria have developed antimicrobial resistance which means that they are not killed by certain antibiotic drugs. Infections with these bacteria are very hard to treat and can be life-threatening. Foodborne bacterial strains can become resistant to antibiotics, particularly those of C. difficile, E. coli 0157:H7 and S. aureus. Hospitalization and intravenous administration of antibiotics of last resort are needed to fight these infections.

To learn more about diagnosis and treatment of foodborne pathogens not described in Background, see CDC’s Diagnosis and Management of Foodborne Illnesses.