11 Aug Microchem will be offering a 10% discount on STEC Detection for July 2020.
Food producers should increase their focus on maintaining product quality and safety amidst the current Coronavirus pandemic. One way of maintaining a strong immune system is by eating foods that are healthy and free of pathogenic bacteria.
Shiga toxin-producing E. coli (STEC) are the most important pathogenic E. coli as they can cause potentially life-threatening illnesses. Microchem is accredited for the detection of STEC using a real-time Polymerase Chain Reaction (PCR). We have a team of well-trained, vastly experienced microbiologists to provide fast turnaround times and accurate results. We pride ourselves on customer service and value all our clients. As such, for the month of July 2020, our clients can enjoy a 10% discount on detection of STEC.
Please contact your Microchem Representatives for more information about our services.
Find detailed information on STEC in the newsletter below.
What is STEC?
Strains of E. coli that produce one or more Shiga toxins are known as Shiga toxin-producing E. coli (STEC) or Verocytoxin-producing E. coli (VTEC). STEC have become pathogenic by acquiring virulence genes through mutation. From a food safety perspective, STEC are the most important pathogenic E. coli as they can cause potentially life-threatening illness.
Numerous E. coli strains are capable of producing one or both Shiga toxins (stx1 and stx2), but not all of them are important human pathogens. STEC strains which cause the attaching and effacing lesions, linked with the most severe forms of illness, possess a combination of the stx genes, stx1/stx2, and the intimin gene, eae. The top STEC strains linked to foodborne illness are E. coli O157, O26, O45, O103, O111, O145 and O121.
STEC in the Environment
While ruminants, in particular cattle and sheep, are the major animal reservoir of STEC, a wide range of animals have been found to excrete STEC in their faeces, including domestic animals, seagulls and houseflies. Infected animals shed the bacteria in their faeces, resulting in contamination of the environment. Person-to-person spread, contaminated water supplies and animal contact are all important transmission routes. The major transmission route is foodborne.
Primary products (such as meat, milk and fresh produce) can be either contaminated directly by faecal material or indirectly via contaminated water or soil. STEC infection is associated with contaminated foods that are eaten without further processing or have been inadequately processed.
Symptoms and Treatment
The illness caused by STEC infection presents with watery or bloody diarrhoea, abdominal cramps and vomiting. Very young children and the elderly are more likely to develop severe illness, but even healthy older children and young adults can become seriously ill.
STEC can cause various illnesses which include Haemorrhagic Colitis (HC), a severe illness involving bloody diarrhoea, Haemolytic Uraemic Syndrome (HUS), a kidney disease that can lead to fatal renal failure, and Thrombotic Thrombocytopenic Purpura (TPP) – an extension of HUS with additional fever and neurological symptoms. It is estimated that STEC infection is the cause of approximately 70% of the cases of renal failure in children. The use of antibiotics during illness has been linked to the development of HUS syndrome.
The consumption of very low numbers of viable VTEC in food is sufficient to cause infection. The dose required for STEC to cause illness will depend on the serotype and virulence factors. For E. coli O157:H7 the infective dose is estimated to be very low (10–100 bacterial cells). Therefore, ready-to-eat foods contaminated with STEC are a food safety risk.
Outbreaks, Recalls, Incidence
Foods that have been associated with STEC outbreaks include those of animal origin and fresh produce that has been subject to faecal contamination from the environment.
Susceptible foods include:
- inadequately cooked ground beef (hamburger patties)
- poorly processed uncooked fermented meat (e.g. salami)
- raw or inadequately pasteurised dairy products
- fresh produce such as leafy greens and sprouted seeds
E. coli does not grow at temperatures below 7°C but can survive in chilled and frozen food. Adequate cooking and prevention of cross-contamination are important control measures for STEC. It is generally recommended that foods (such as hamburger patties) are thoroughly cooked to a core temperature of 75°C. For foods which will not be cooked before consumption, such as fresh fruit and vegetables, contamination at the growing and distribution stages should be prevented through good agricultural practice.
Microchem is accredited for the detection of STEC using a real-time Polymerase Chain Reaction (PCR) method that is AFNOR certified for the multiplex detection of stx1/stx2 and eae genes. This method detects STEC virulence genes directly, is fast and sensitive while also being cost-sensitive. Foodborne illness if linked to strains that contain all three virulence genes, which can be easily detected and confirmed using PCR technology.
Other Service Offered by Microchem
- Routine Food Microbiology Analyses
- Foodborne Pathogen Analyses
- Water Microbiological Analyses
- Shelf-Life Analyses
- Hygiene Inspections and Reports
- Microbiological Swabbing
- Food Chemistry
- Nutritional Analyses
- Trace Elemental and Heavy Metal Analyses
- Food Colourants (Azo Dyes)
- Vitamin Analyses
- Water Chemical Analyses
- Pesticide Analysis – Multi-Residue Analysis
View our SANAS accreditation certificate
Centre for Food Safety, Food and Environmental Hygiene Department Hong Kong, Microbiological Guidelines for Food, August 2014.
Health Protection Agency, Guidelines for Assessing the Microbiological Safety of Ready-to-Eat Foods, London: Health Protection Agency, November 2009.
Food Safety Authority of Ireland, Guidance Note: Guidelines for the Interpretation of Results of Microbiological Testing of Ready-to-Eat Foods Placed on the Market (Revision I), 2014.
Food Standards Australia New Zealand, Compendium of Microbiological Criteria for Food, September 2018.