Compared to bacteria Viruses are very small organisms and can not reproduce and multiply outside a living cell and therefore can not grow on or inside food as bacteria do. However, raw produce may become contaminated by viral particles with exposure to contaminated water, soil, dust or surfaces. The virus could then infect the consumer of the product if it is consumed raw. The infective dose of most viruses is extremely small (sometimes as few as 10 viral particles), so prevention of contamination is essential.
Some Viral pathogen and Main characteristics and effect on human health
Noroviruses are a group of viruses that cause gastroenteritis. They are found in the intestines of infected persons, who can easily pass them on. The term Norovirus was recently approved as the official name for this group of viruses (other names that have been used include Norwalk-like viruses) The symptoms of Norovirus illness usually include nausea, vomiting, diarrhoea, stomach cramps, low-grade fever, chills, headache and muscle aches. The illness often begins suddenly, and the infected person may feel very sick. In most people, the illness is self-limiting and lasts for about 1 or 2 days.
Rotavirus is the most common viral cause of severe diarrhoea among children worldwide. The primary mode of transmission is faecal–oral. Because the virus is stable in the environment, transmission can occur through ingestion of contaminated water or food and contact with contaminated surfaces. The disease is characterized by vomiting and watery diarrhoea for 3-8 days, and fever and abdominal pain occur frequently.Adults can also be infected, though the disease tends to be mild.
The Hepatitis A virus can be transmitted from one infected person to another by contamination of food or water.Food borne cases of Hepatitis A are recognized to occur worldwide and can mainly be prevented by proper hygiene practices during handling of fresh food.