Virus foodborne disease

Viruses are frequent causes of foodborne disease in the US and other countries. Food borne viruses infect through ingestion and are passed through the feces.

Any virus that is excreted in feces in sufficiently large numbers and manages to survive outside the body of the host long enough to contaminate food has the potential to spread through this route.

Viruses differ from bacteria in that they are smaller, require a living animal or human host to grow and reproduce, do not multiply in foods and are nor complete cells.

Viruses involved in foodborne disease outbreaks include, but are not limited to norovirus, hepatitis A virus, human rotavirus, hepatitis virus, astrovirus, sapovirus, aichi virus and adenovirus, as well as human enteroviruses such as echoviruses, polioviruses, group A and B coxsachieviruses.

The great majority of these are RNA viruses, often small and containing single-stranded RNA. They infect via the intestinal lining, but some are transported to the over (and occasionally other organs) before causing disease.

Norwalk and Norwalk-like viruses are the leading reported cause of foodborne viral illness. A member of the Calicivirus family of viruses, Norwalk virus particles are 27 to 38 nm in diameter and consist of a single positive strain of RNA.

Norwalk virus was first discovered following an outbreak of epidemic gastroenteritis in a Norwalk, Ohio, elementary school in 1968.

Outbreaks of ‘food poisoning’ or foodborne gastroenteritis over the years have been assumed to be caused by bacteria, whether or not such organisms are identified.

Washing hands and cooking foods are probably the two measures that contribute the most to preventing foodborne viral disease.
Virus foodborne disease

Guillain–Barré syndrome

The best-known complications associated with foodborne pathogens include reactive arthritis, hemolytic uremic syndrome and Guillain–Barré syndrome.

Guillain–Barré syndrome is a type of peripheral neuropathy – Ga condition involving nerves extending into the head, trunk and limbs.

It is a disorder in which the body’s immune system attacks part of the nervous system. The first symptoms of this disorder include varying degrees of weakness or tingling sensation in the legs.

Campylobacter may be the most common precipitating factor for the Guillain–Barré syndrome, which is now one of the leading causes of paralysis from disease in the United States.

Campylobacter infections occur in all age groups, with the greatest incidence in children under 1 year age.

Guillain–Barré syndrome mortality, caused the primarily by acute respiratory failure, can vary from 4 to 20%.
Guillain–Barré syndrome

Foods that are most commonly associated with foodborne illnesses

*Raw foods of animal origin are the most likely to be contaminated; that is, raw meat and poultry, raw eggs, unpasteurized milk, and raw shellfish. Because filter-feeding shellfish strain microbes from the sea over many months, they are particularly likely to be contaminated if there are any pathogens in the seawater.

*Foods that mingle the products of many individual animals, such as bulk raw milk, pooled raw eggs, or ground beef, are particularly hazardous because a pathogen present in any one of the animals may contaminate the whole batch. A single hamburger may contain meat from hundreds of animals. A single restaurant omelet may contain eggs from hundreds of chickens. A glass of raw milk may contain milk from hundreds of cows. A broiler chicken carcass can be exposed to the drippings and juices of many thousands of other birds that went through the same cold water tank after slaughter.

*Fruits and vegetables consumed raw are a particular concern. Washing can decrease but not eliminate contamination, so the consumers can do little to protect themselves. Recently, a number of outbreak have been traced to fresh fruits and vegetables that were processed under less than sanitary conditions. These outbreaks show that the quality of the water used for washing and chilling the produce after it is harvested is critical. Using water that is not clean can contaminate many boxes of produce.

*Fresh manure used to fertilize vegetables can also contaminate them. Alfalfa sprouts and other raw sprouts pose a particular challenge, as the conditions under which they are sprouted are ideal for growing microbes as well as sprouts, and because they are eaten without further cooking. That means that a few bacteria present on the seeds can grow to high numbers of pathogens on the sprouts. Unpasteurized fruit juice can also be contaminated if there are pathogens in or on the fruit that is used to make it.
Foods that are most commonly associated with foodborne illnesses

Foodborne illness caused by cross contamination

Food borne illness refers to illness caused by the ingestion of contaminated food and beverages. Foodborne illness can be caused by either an infection or an intoxication.

Cross contamination is one of the major causes of foodborne illness and can easily occur during preparation.

The contamination of food by bacteria that occurs when the food comes into contact with surfaces previously touched by raw meat, poultry or seafood.

Cross contamination occurs when a bacteria that’s present in one food accidently spreads to another food, usually through improper handling and storage.

For example, Compylobacter jejuni are very common cause of food borne illness. This pathogen is associated with raw poultry an sometimes raw milk. Illness are often caused when cross-contamination between these source and ready to eat foods, such as salads, occurs during food preparation.

The major cause of food borne illness is unsanitary food handling. To reduce risk of contamination, proper personal hygiene and hand washing must be practiced by all food handlers. Steps must be taken to prevent cross contamination between raw and cooked foods and though food handlers.

Cross contamination can be avoided by:
*Preventing raw and cooked foods touching each other. Never mixed food products when restocking.
*Preventing blood and juices from raw foods dripping onto cooked foods
*Preventing bacteria from being transferred on hands, knives, utensils, chopping boards or work surfaces.
*Properly clean and sanitize utensils, equipment and surfaces.
*Clean and sanitize work areas.

Foodborne illness caused by cross contamination

Foodborne illness bacteria: Clostridium perfringes

Foodborne illness bacteria: Clostridium perfringens Clostridium perfringens contamination Clostridium perfringens (both vegetative cells and spores) is found in soil, sewage, manure, water, and dust. It has been found in the intestinal tract of healthy humans and animals. 

Many raw foods, particularly meats and vegetables, are likely to be contaminated with Clostridium perfringens when they reach food preparation areas. Outbreaks of illness usually involve foods high in protein. Clostridium has a requirement for 12 to 13 amino acids.) The foods include: meats, poultry, soups, gravies, sauces, stews, and casseroles. 

When food is cooked, the vegetative cells are destroyed. However, spores survive if protein-rich foods, such as roast beef, turkey, gravies,, and sauces are allowed to cool slowly and remain at temperatures that allow outgrowth of the surviving spores, vegetative cells will multiply rapidly to large numbers in the food and create a significant hazard. 

Foodborne illness 

Foodborne illness due to Clostridium perfringens usually occurs to 24 hours after ingestion. The illness is caused by ingestion of a large number of vegetative cells. When the vegetative cells reach the intestine, they form spores and release an enterotoxin that causes diarrhea and severe abdominal pain. Nausea is uncommon; fever and vomiting are unusual. 

Fatalities can occur in the very young and elderly. The infective dose is a cell population of 500,000 cells or more per gram of food. This number of cells can form rapidly in foods because Clostridium perfringens has a very rapid generation time and can double ion number every 7 minutes at 42 C. Clostridium perfringes grows at temperatures between 15 C and 53 C. 

Foodborne illness bacteria: Clostridium perfringens