Microbial foodborne pathogens

Common pathogens

Common pathogens

Bacillus cereus, Campylobacter Jejuni, Escherichia coli, Listeria monocytogenes.

Salmonella morphology

Family enterobacteriaceae. G-ve, rod shape, catalase positive. Non spore forming.

Salmonella function

Facultative aerobes capable of generating ATP when oxygen is available. Produces gas from D-glucose, uses citrate as a sole carbon source.

Salmonella optimum temperature.

Mesophilic with optimum growth temperature between 35 and 37oC.

Salmonella species (main).

Salmonella enterica, salmonella bongori.

Salmonella serotypes

Salmonella Para typhi, choleratis, typhimurium.

Listeria morphology

G+ve, psychotropic bacteria, rod shape motile using flagella.

Listeria function

Non spore forming, facultative anaerobes.

Listeria optimum growth temperatures

Growth between 30-37oC, capable of growing between 1-44oC, resistant to heat, freezing and desiccation.

Six species of listeria

Monocytogenes, ivanovii, seeligeri, innocua, grayi, welshmeri.

Escherichia coli (E.coli) morphology

Family of enterobacteriaceae, G-ve, rod shaped.

E. coli function

Facultative anaerobe, motile and non spore forming.

Important pathogens of E. coli.

0157, 026, 0103, 0111, 045, 0121

Campylobacter morphology

G-ve, slender, curved, rod shaped

Campylobacter functions

Microaerophilic, requires reduced oxygen levels. Sensitive to stresses such as drying, heating, disinfectants and acids.

Bacillus cereus

G+ve, facultative anaerobe, spore forming.

Foodborne viruses

Enteric virus main type, 58% of illnesses due to norovirus.

What is the most common foodborne virus?

Norovirus

Most common food causes of norovirus

Infected food handlers, molluscan shellfish, contaminated produce.

Hepatitis A/E

Inflammation of the liver commonly caused by viruses, transmitted by the fecal-oral route.

Astrovirus

Suspected foodborne however less associated with incidences of infection. Associated with gastroenteritis and implicated in foodborne transition.

Human rotavirus

Major contributor of dihhoreal diseases leading to severe dehydration and death.