SEOUL - South Korea has decided to conduct emergency inspections on milk sold in the market by four major dairy companies, to check the presence of formalin, a state quarantine service said Friday.  

The National Veterinary Research and Quarantine Service (NVRQS) said it will collect and test milk products made by the companies with high market share, namely Maeil Dairies, Namyang Dairy Products, Seoul Milk and Dongwon Dairy Foods, to detect formalin, a liquid form of formaldehyde.  

The move comes after Maeil Dairies was found to have produced milk from cows given feed tainted with formalin.  

Formalin, a liquid form of formaldehyde gas, was largely used in the past as a disinfectant, pesticide and bactericide for preservation of biological specimens.

But its use has dwindled over the years due to health concerns. The NVRQS said no official screening system exists for formalin in milk products because the substance is not allowed to be used as a plant additive. Therefore it will adopt the formalin checking procedure used for beer.