McDonald’s Corp. (MCD) and Yum! Brands Inc. (YUM) halted buying meat products from a Shanghai supplier while authorities investigate allegations that the company sold chicken and beef past its expiration date. McDonald’s asked all its outlets to stop using products from Shanghai Husi Food Co., according to statements on the companies’ official Chinese microblog yesterday. Yum’s KFC and Pizza Hut restaurants did the same, the company said in a separate microblog statement.