FOOD BORNE DISEASES

Food borne diseases are diseases caused by the ingestion of food borne pathogens. They are generally regarded as gastrointestinal infections that occur when microbes are ingested via contaminated foods or food products. In cases of food borne diseases, the ingested food borne pathogen grows within the gastrointestinal tract (GIT) or gut of the affected individual; and this microbial growth result in some clinical conditions or symptoms such as vomiting, abdominal cramp and profuse stooling that infer possible cases of food borne illnesses.

Food borne diseases also encompass food intoxifications and food poisoning, but there are some variations that exist between these health anomalies (i.e. food intoxifications, food poisoning and food borne diseases) that occur in humans following the consumption of food and food products that are heavily contaminated by pathogenic microorganisms.

Table 1 shows the list of some pathogenic microorganisms that are mainly implicated in most cases of food borne diseases. Food borne diseases usually result from the consumption of foods or water that contains viable or living pathogenic microorganisms that invade the host’s GIT to cause gastroenteritis. According to the World Health Organization (WHO), unsafe and microbial-contaminated food and food products portend great health and economic consequences.

Aside the morbidity and mortality associated with the consumption of food and food products contaminated by pathogenic microorganisms, a lot of resources are expended globally to contain the health consequences of food borne illnesses including cholera, botulism, salmonellosis, staphylococcal poisoning and other gastroenteritis caused by food borne agents. Food borne outbreaks has been reported in recent times in most parts of the world inclusive of sub Saharan Africa; and the trend is on the increase owing to the inadequacies associated with food handling and processing in some quarters.

To ensure food safety and good quality of processed foods, it is critical to take food hygiene and monitoring of food products for possible contamination by food borne pathogens seriously. Most of the environments where food is being processed are unhygienic, and the equipment and personnel involved in food processing do not imbibe strict hygienic procedures that are capable of minimizing microbial contamination of these foods.

Salmonellosis (caused by Salmonella species), traveler’s diarrhea (caused by pathogenic strains of E. coli), botulism (caused by Clostridium botulinum), cholera (caused by V. cholerae), shigellosis (caused by Shigella species), staphylococcal food poisoning (caused by pathogenic strains of S. aureus) and listeriosis (caused by L. monocytogenes) are typical examples of food borne illnesses.                

Table 1. Summary of microorganisms that cause food-borne infections in man

Pathogen	Type of microorganisms	Disease	People At risk	Mode of transmission
Listeria monocytogenes	Bacteria	Listeriosis	Neonates, infants, pregnant women, the elderly and immunocompromised host	Contaminated food e.g. meat, dairy foods and unpasteurized milk
Adenovirus group	Virus	Gastrointestinal infections	People of all ages	Contaminated food
Salmonella serotypes	Bacteria	Salmonellosis	People of all age groups	Contaminated food e.g. vegetables
Girdia lamblia	Protozoa	Girdiasis	People of all ages	Contaminated food e.g. meat
Norovirusgroup	Virus	Gastroenteritis	Children and adults	Contaminated food e.g. shellfish, fruits and ready-to-eat food
Shigella dysenteriae	Bacteria	Shigellosis	Infants, malnourished children and adults	Contaminated vegetables
Escherichia coli strains	Bacteria	Gastrointestinal infections	Travelers, and people of all ages	Contaminated food e.g. vegetables and meat
Toxoplasma gondii	Protozoa	Toxoplasmosis	People of all ages	Raw and undercooked food e.g. meat
Yersinia enterocolitica	Bacteria	Gastroenteritis	Infants & children	Contaminated food
Coronavirus group	Virus	Gastrointestinal infections	People of all ages	Contaminated food
Staphylococcus aureus	Bacteria	Staphylococcal food poisoning	People of all ages	Contaminated food
Rotavirus group	Virus	Gastrointestinal infections	People of all ages but mostly common in children & infants	Contaminated food
Clostridium botulinum	Bacteria	Botulism	Children, adults, infants and travelers	Contaminated food e.g. smoked fish and vegetables
Cryptosporidium parvum	Protozoa	Cryptosporidiosis	Immunocompromised hosts	Undercooked or raw food
Campylobacter jejuni	Bacteria	Gastroenteritis	People of all ages	Contaminated food e.g. poultry and dairy food products

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