Genetic ID launches PCR test for oregano authenticity

By Joseph James Whitworth contact

- Last updated on GMT

Professor Chris Elliott found other ingredients included olive, myrtle leaves and cistus
Professor Chris Elliott found other ingredients included olive, myrtle leaves and cistus

Related tags: Polymerase chain reaction

Genetic ID (Europe) has launched a rapid detection method of myrtle and olive leaves in dried oregano.

The food authenticity test lab is applying a real time PCR based semi-quantitative method and said the service is available with a turnaround time of the following day.

The method was developed in-house to assist food manufacturers with verifying authenticity of dried oregano without cross-reaction to other plant species.

A quarter of dried oregano was found to contain other ingredients according to a study published by the consumer watchdog Which? last month​.

The Seasoning and Spice Association (SSA) said to ensure quality and integrity all companies have controls in place to protect themselves and customers from fraud.  

Product verification

Dr Konstantin Rizos, technical manager and client relations management at Genetic ID (Europe), said real time PCR is a fast, specific and economic method.

“This testing is recommended to verify that the used oregano is really oregano and not just an oregano blend,” ​he told FoodQualityNews.

“Myrtle and olive material do not seem to be present only in forensic traces but in significant amounts in several products. This might affect the labelling of the final product.”

Authenticity of the dried herb sold through a number of retailers was called into question following a study by Professor Chris Elliott which revealed 25% of 78 samples purchased in the UK and Ireland contained ingredients other than oregano.

According to the study, some samples contained 30-70% of foreign botanic material, most commonly olive and myrtle leaves.

Normally it takes about one month from test design to final experimental validation but Genetic ID had developed primers for these species for a different project so could react quickly.

To filter out samples that contain only traces from those with substantial amounts of foreign botanical materials, the firm is applying a reporting LOD of 1%.

Customers can combine it with GMO or other species tests to keep testing costs down.

Rizos said costs are reduced compared to testing these parameters individually.

“There are various options to combine this test with other methods, e.g. products could be tested for GMOs as well as relevant allergens (e.g. celery, mustard, soy, nuts).

“A combination of constant horizon scanning and vulnerability assessment as requested in the new BRC version will help to maintain consumer confidence and to exert sufficient control over the supply chain.”

Genetic ID is offering turn-around times (TATs) from standard three business days upon sample arrival through to an express service with results by noon the following business day.

RSSL testing tools

Meanwhile, RSSL has also launched two levels of testing for verifying authenticity of dried oregano.

One involves microscopy, which is suitable for detecting significant levels of adulteration so could work to detect the 30-70% levels reported in the study.

The other is analysis by GC-MS which can compare the volatile chemical profile of a trusted sample of pure oregano with those of the test samples.

This would allow chemists to detect any obvious differences between the two which would be indicative of cross contamination or adulteration. 

Karen Masters of RSSL said as with any technique there are limitations and a positive result does not necessarily imply deliberate adulteration. 

"However, the immediate concern is to eradicate the instances of gross contamination that the Which? report exposed, and our methods are capable of identifying contamination or adulteration at the levels reported."​  

Related topics: Food Safety & Quality

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