TOKYO – McDonald's Holdings Co. Ltd. in Japan is investigating a plant in Thailand that may have produced a McDonald's chicken nugget contaminated with foreign matter, according to news reports.

A piece of vinyl was recently found in a chicken nugget sold at a McDonald's in Misawa. In response, the chain stopped sales of chicken nuggets that were produced on the same day at the Thai plant. McDonald's Japan began sourcing its Chicken McNuggets from three plants in Thailand following alleged food-safety problems with its Chinese supplier, Shanghai Husi Food Co.