Scientists develop 12-hour salmonella test

By George Reynolds

- Last updated on GMT

Related tags: Polymerase chain reaction

Danish scientists have developed a 12-hour detection method for
salmonella in meat and poultry, which could slash the time of
processors need to wait before allowing shipments to leave.

Current salmonella tests using polymerase chain reaction (PCR) methods can take up to five days and result in costly delays or recalls if shipments are moved before results are known. The 12-hour test was developed based on eight hours of pre-enrichment, followed by automated DNA extraction and a sensitive real-time PCR. The method, published by the American Society for Microbiology,​ attempts to yield the highest amount of cells and DNA. Scientists examined analysis of larger volumes from pre-enriched samples and introducing wash steps prior to DNA extraction. They also regulated the amount of paramagnetic particles, eluted the DNA in reduced volumes, and increased the PCR template volume. For analysing meat samples, the scientists found that increasing the initial sampling volume from one to five ml and increasing the amount of paramagnetic particles to 90 microlitres led to improved results. However, results showed that washing the pellet and eluting the DNA in reduced volumes had no positive effects and reduced reproducibility. Increasing the amount of PCR template DNA from 5 to 20 µl doubled the threshold cycle value. Salmonella is one of the largest causes of food-related illness in Europe. Earlier this year, a study by the European Food Safety Authority (EFSA) published a study that found salmonella infected almost one if four of broiler chickens. The study found there were 192,703 reported cases of salmonellosis and 183,961 of campylobacteriosis cases reported during 2004 in the EU's 25 member states. The cases are out of a total of 400, 000 human cases of zoonoses reported. Most of the cases were foodborne and associated with mild to severe intestinal problems.

Related topics: Food Safety & Quality

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