Millions of cans of a popular ready-to-drink diet product are being recalled in the United States after tests showed the liquid meals could be tainted with bacteria, the manufacturer said Friday. Unilever United States announced it was recalling 'all Slim-Fast ready-to-drink products in cans, due to the possibility of contamination with Bacillus cereus, a micro-organism which may cause diarrhea and possibly nausea and/or vomiting.' Unilever spokeswoman Anita Larsen said the recall affects some 10 million cans across the country. The bacteria was discovered during routine testing, she added. The recall does not concern other Slim-Fast products, such as meal bars or powder, according to Unilever. 