STEC Analyses - Eurofins Scientific AG
Incidence and Transmission of STEC (Shiga Toxin-Producing Escherichia coli)
Escherichia coli bacteria are a natural part of the intestinal flora of humans and animals. The detection of Escherichia coli in food serves as an indicator of contamination by feces. The so-called shigatoxin-producing E. coli (STEC) are a special subgroup of Escherichia coli bacteria. They produce so-called Shiga toxins and can cause diarrhea and more serious illnesses in humans.
Ruminants such as cattle, sheep, goats, deer and stags are natural reservoirs of the bacteria, but dairy products and plant-based foods such as sprouts can also be affected. Flours and other natural products (e.g. dried grasses) have recently tested positive. An evaluation by the Federal Institute for Risk Assessment in Germany (BfR, January 20, 2020) found that “STECs are detectable in a significant proportion (10 to 30%) of the [tested] flours”. This was based on the results of the nationwide monitoring plan (BüP) in 2018. 50 STEC were detected in 328 wheat, spelt and rye flour samples tested (15.2%), with several sub-samples being taken and tested in some cases (BVL 2019).
1. Raw Milk and Raw Milk Products:
EHEC is commonly found in raw milk and raw milk cheese.
Inadequately heated dairy products may be a source of STEC infection.
2. Raw and ground meat:
EHEC can be found on or in raw or undercooked meat.
Ruminants such as cattle but also spreadable raw sausages are particularly at risk.
3. Fruits and vegetables:
Raw fruits and vegetables that grow in or near the ground can also be contaminated with EHEC through contaminated water or cattle manure.
Unpasteurized apple juice, raw leafy greens (e.g., sprouts, spinach, lettuce) are potential sources.
4. Cross-contamination:
EHEC can be transmitted from contaminated, usually raw food to other ready-to-eat foods through cross-contamination (cookie-dough).
Analytical methods:
Shigatoxin-producing Escherichia coli, STEC for short, are considered important pathogens. The quantitative Escherichia coli method according to ISO 16649-2 is based on the detection of the enzyme β-D-glucuronidase and uses a relatively high incubation temperature. As a result, not all Escherichia coli serotypes can be detected with this method, especially serotype O157, a frequently occurring and critical STEC! Therefore, qualitative analysis for STEC is crucial to ensure consumer and food safety.
Laboratory testing can detect STEC infections early, identify the sources and prevent outbreaks. Through regular monitoring and analysis, potentially hazardous food can be identified and risk mitigation measures can be taken. We offer the tests directly from Schönenwerd, Switzerland, accredited!
