A resident surnamed Li bought a box of Sanyuan milk at Lotte Mart in Fengtai district for his pregnant wife, only to find it has gone sour and was foaming after he opened it, the Xinhua News Agency reports.

Li called the hotline of the Sanyuan milk company, but no one answered. The milk Li bought still had five days before it expired. Li did not know whether the fault lay with Lotte Mart, who may have changed the production date in order to promote the milk, or Sanyuan. Li kept other boxes of milk he bought along with the soured one so he could give it to Sanyuan to examine, but the company did not reply to his offer for more than 10 days.