VietNamNet Bridge - Two laboratories have offered different conclusions about the same vegetable samples, with one saying the vegetables were safe, while the other saying the toxicity level was 3.5 times higher than the permitted level.

Nguyen Thi Kim Thoa from the Ministry of Justice spoke about the issue at a ceremony launching the movement against unsafe food in Hanoi.

According to Nguyen Duy Thinh from the Institute of Biotechnology and Food, an arm of the Hanoi University of Technology, many factors affect testing, including the methods of taking samples and analysis, the quality of laboratories and the status of equipment. 

“If you take samples from three different locations on the same plant, you will receive three different testing results, because the chemical residue at different locations is different,” he explained.

“If farmers have just sprayed chemicals, toxicity would be found most on top of plants. Meanwhile, if they sprayed pesticide many days ago, only a little toxicity can be found on top of plants,” he said.

Therefore, in order to get the most reliable testing results, it is necessary to take samples from different locations on the same plants, and from different places of the same vegetable fields.

Two laboratories have offered different conclusions about the same vegetable samples, with one saying the vegetables were safe, while the other saying the toxicity level was 3.5 times higher than the permitted level.

After that, the samples must be mixed, cut into small pieces and divided equally before they are tested. In case scientists want to learn about the phytochemicals infection in some certain areas, they need to take many samples on different days

To discover prohibited substances farmers might use in animal husbandry, it is necessary for technicians to find where the toxicity could be concentrated. If toxicity is accumulated in the liver, scientists would have to take many samples from the liver, and mix them and analyse them. 

If toxicity is found in many organs, scientists would take samples from many different places and take the average. 

In principle, samples must be tested at laboratories which can meet the standards, to be able to give exact results. Besides, the equipment used at laboratories must be inspected, while the technicians must be qualified. 

Therefore, according to Thinh, in order to improve the food testing system, Vietnam will have to upgrade laboratories and train technicians. However, this would be very costly.

A machine that analyses antibiotic content with the accuracy rate of one per billion is much more expensive and it needs to be regulated by much more skilled technicians than a machine with the accuracy rate of one per million or one per thousand.

KH & PT