Fish Microbiology and Quality Assurance

Unit 5 - Foodborne pathogens

5.1 Foodborne pathogens
Several human pathogenic microorganisms are associated with food and water in their natural environment, and foods also get contaminated with pathogens during handling and processing. Thus, ingestion of food or water contaminated with pathogens leads to food poisoning affecting the health of consumers.

Food poisoning
Food poisoning is an illness caused either by the ingestion of toxin elaborated by the pathogens or from the infection of the host through the intestinal tract due to ingestion of live organisms.Food poisoning by bacteria can be of two types;

• Bacterial food intoxication
• Bacterial food infections

Bacterial food intoxication
It is a food borne illness caused by the presence of a bacterial toxin formed in the food. It is caused due to consumption of food containing pre- formed toxin but not live bacteria.
Two types of food intoxications are caused by bacteria.

• Botulism: Food poisoning caused by the ingestion of food containing toxin produced by Clostridium botulinum.
• Sataphlococcal intoxication: Food poisoning caused by the ingestion of food containing pre-formed toxins produced by Staphyllococcus aureus

Bacterial food infections
This is a food borne illness caused by the entrance of live bacteria into the body through ingestion of contaminated food. The illness mainly results from the reaction of the body to pathogen’s presence or their metabolites.
Ex: Salmonellosis, C. perfringes illness, Cholera, V. parahaemolyticus infection etc

Sources of Pathogens
Seafood/ foods of aquatic origin have potential to cause human illness. The entry of bacterial pathogens to aquatic environment /consumers results from the following:

• Pollution of aquatic environment from sewage or animal wastes.
• Consumption of raw or semi processed contaminated food/ water.
• Infected domestic animals used for food. (Ex: Salmonella in poultry)
• Unsanitary practices of product handling through food handlers.
• Presence of naturally associated human pathogens in aquatic foods/ environment