Shares in Tingyi (Cayman Islands) Holding Corp slumped almost 5 per cent yesterday on reports suggesting its noodles may contain higher-than-normal amounts of bacteria. The Taiwan-based instant noodle and rice-cracker maker saw heavy selling in the market with 36.33 million shares traded against an average of six million shares last month. The shares closed 4.76 per cent lower at $2. The company defended itself yesterday against local press articles citing mainland reports that claimed a Chinese Government bureau study on the seasoning bags and instant noodles under Tingyi's Master Kang brand found they failed to meet certain hygiene standards. Tingyi spokesman Daniel Tseng said the study did not offer any bacteria benchmark on the seasoning bags. Tingyi said last night that the mainland bureau confirmed on June 26 the test did not suggest Tingyi's products failed any mainland hygiene standards. It said the reports have prompted Tingyi to investigate the quality control systems at its plants in Tianjin and Hangzhou where the alleged problem noodles were said to have come from.