Ice cubes used by fast-food giants KFC, McDonald's and Guangzhou-based Kungfu at branches in Beijing contained bacteria far in excess of the national limit, according to China Central Television.
Some were even dirtier than toilet bowl water, CCTV said.
The three fast-food operators said they were carrying out inspections and enhancing disinfection at the stores involved.
CCTV reporters sent ice cubes from the Chongwenmen outlets of KFC, McDonald's and Kungfu for lab tests. The KFC ice cubes were 20 times the limit, and 13 times higher than water samples taken from toilet bowls.
The amount of bacterial colonies found at McDonald's and Kungfu ice cubes reached 120 CFU and 900 CFU (colony-forming units) per milliliter respectively, exceeding the national limit of 100 per milliliter.
The CFU level of Kungfu's ice cubes was six times higher than toilet water, CCTV reported.
The intake of food with excessive level of colonies could lead to dysentery and diarrhea, said Ding Ke, an associate professor of food science and engineering of the Beijing University of Agriculture.
Wu Jing, a doctor at Beijing Shijitan Hospital, said excessive amount of colonies meant a higher chance of pathogenic bacteria and may make food rotten and stale.
Dirty ice machines and a poor awareness of food safety such as the importance of washing hands and poor sterilization procedures are some of the reasons that may lead to high level of bacterial colonies, experts said.
The CCTV report has been reposted more than 99,000 times on Sina Weibo since Saturday.It's no consolation that the story goes on to say that it's not much better in the fast-food restaurants in the United Kingdom.