Fact Sheet: Salmonella spp
- Salmonella is a rod-shaped, Gram negative, non-motile bacteria, which does not form spores.
- This bacterium was first discovered in the 1880s and named Bacterium suipestifer. Later it was renamed Salmonella after the scientist who discovered it, Dr Daniel Salmon.
- Most reptiles and amphibians carry Salmonella.
- Salmonella diseases are zoonotic, spreading from animals to humans, and also from human to human.
- Salmonella move through their host’s intestines via flagella.
- There are approximately 2,500 different strains of Salmonella.
- Salmonella infections have been found to be more frequent in summer than in winter.
- Even after symptoms of Salmonella infection have stopped, it is still possible to infect others. That is why it is advisable to wait another 48 hours after symptoms have disappeared to go back to work or school.
- Salmonella is not killed in the freezing process.
- According to the U.S. Centers for Disease Control and Prevention, approximately 1.2 million illnesses occur due to non-typhoidal Salmonella annually.
- Some people may develop reactive arthritis when suffering from a Salmonella infection.
- Salmonella infections are known as salmonellosis. It takes 12 to 72 hours for symptoms to develop.
- Salmonella infections generally cause abdominal cramps, nausea, chills, loss of appetite, diarrhoea and fever.
- The most common ways of becoming infected by Salmonella are through contaminated eggs, dairy, poultry and meat products.
- After being eaten, Salmonella passes through the stomach to the intestine, where it binds to and passes through the intestinal wall.
- Salmonella has evolved mechanisms to prevent our immune system from attacking it.
- The best way of avoiding Salmonella infection is to cook food thoroughly and perform good handwashing technique.
In the Lab / at Wickham Laboratories Ltd
- Media such as Xylose Lysine Deoxycholate agar (XLD) can be used to examine for the presence / absence of S. abony. Shiny black colonies, 1-2 mm in diameter is indicated as a positive result. This is then confirmed using identification techniques such as MALDI-ToF. (Matrix Assisted Laser Desorption Ionization-Time of Flight).
- The presence / absence of this bacteria is also included in the QC testing for products with raw materials of natural origins. It may also be included in testing for other products if the risk assessment by the client deems it to be necessary.
- Salmonella spp are predominantly a foodborne organism found due to faecal pollution in the supply chain however it must be considered as part of the risk assessment of your product to determine if this testing needs to be included.
- Most food ingredients and food products will undergo batch testing for Salmonella to prevent outbreaks. From clinical specimens, Salmonella infection is identified by culturing a sample from an infected patient and evaluating it via a combination of appearance, serology and biochemical testing. If diagnosed, it should be reported to any treating clinician and public health organisations.