The scare over contaminated products made by the New Zealand-based dairy giant Fonterra has aggravated public concerns about the safety of milk powder products and tarnished the image of foreign food brands in China.

Fonterra, the world's largest dairy producer, admitted on Saturday that some of its whey protein concentrate, which is used to make infant milk powder and other products, had been contaminated with bacteria that can cause the sometimes fatal illness botulism.

The confidence of Chinese consumers in foreign brands is likely to have been further shaken by reports of dubious behavior by US-based Abbott Laboratories.