Hong Kong's Polytechnic University develops faster system to identify 'gutter oil'

PUBLISHED : Tuesday, 30 June, 2015, 3:37am
UPDATED : Tuesday, 30 June, 2015, 3:37am

Polytechnic University scientists have developed a method that can rapidly distinguish between so-called "gutter oils" at the centre of a series of food safety scandals and safe edible oils.

Traditionally, testing can take hours and is labour-intensive, but the PolyU team has adopted a technique that uses lasers to ionize samples. They then analyse the oil spectra - broadly speaking, a comparison of the oil components and the intensity with which they are found.

"Oil problems have become international with Taiwan, Hong Kong and even Singapore involved in 'gutter oil' scandals, but the present detection methods are complicated and time-consuming," said Dr Yao Zhongping, who led the project. "Our project saves on consumables and is automatic."

The process can screen samples in five minutes as opposed to the traditional approach, which requires the pretreatment and separation of samples before the same result is achieved.

Analysis of the spectra categorises edible oils and those deemed as "fake oils".

More than 30 samples have been tested and used as resources for a spectral library, but 1,000 remain to be tested, Yao said.

The project was developed by the Food Safety and Technology Research Centre under PolyU's department of applied biology and chemical technology.

The project is also looking at the possibility of converting "gutter oil" into biodiesel, said Dr Joseph Ka-fu Yung, the leader of a second project.

In October last year, the Centre for Food Safety banned all animal fat and oil imports from Taiwan after a Kaohsiung oil supplier was found to have sold edible oils containing industrial lard oil and "gutter oil" - oil recycled from restaurants and leather processing. The local food industry was heavily involved in the scandal as about 70 per cent of the lard used by Hong Kong bakeries comes from Taiwan.

"We are now in discussion with government and companies for future cooperation," said Yao, although he declined to disclose the partners.