A Hong Kong university has devised a way to screen for so-called “gutter oils” quickly while identifying edible oils that are safe to eat.
Current oil screening can take several hours to discount the presence of gutter oils, which are waste oils, often from industry, that have been illegally repurposed for human consumption.
Several gutter-oil scandals have taken place in recent years across Asia, most recently in Taiwan, where events there saw mass arrests and the downfall of a cabinet minister. As a result, the country has seen a dramatic fall in consumer confidence.
By setting up a simple analytical protocol and a spectral library of edible oils, Hong Kong Polytechnic University is now able to determine the authenticity of a labelled edible oil sample within five minutes.
Food safety tests for edible oil authentication until now would involve sample pre-treatment, chromatographic separation to separate the mixture and, finally, mass spectrometric detection.
With these, officials can detect certain food residue markers, or the discovery of toxic and carcinogenic chemicals within a sample, although the system is time consuming and inflexible.
The new system features a simplified method for the direct analysis of edible oils using matrix-assisted laser desorption/ionisation mass spectrometry (Maldi-MS).
Yao Zhongping, who led the testing project, said: “Oil problems have become international with Taiwan, Hong Kong and even Singapore have been involved in gutter-oil scandals, but the present detection methods are complicated and time-consuming. Our project saves on consumables and is automatic.”
High quality and highly reproducible Maldi-MS results can be obtained and a preliminary spectral database of labelled edible oils. Because different edible oils have separate Maldi-MS spectral patterns, authenticity can be determined in five minutes by comparing a spectrum with those of its labelled oil.
The researchers expect to spend the next two years working on a more complete Maldi library of edible oils. More testing of samples with different Maldi-MS equipment will be carried out to further validate the new approach.