Lamb
In early 2013, a Radio-Canada article has reported that there were sellers selling rats as lambs! The police went on to arrest 900 people involved in this incident. They also seized 20,000 tons of rat meat.
Beef
A website called Voyage-Chine said that beef is double the price of pork in China. In an effort to save money, a lot of companies just add borax-based food additives to the pork so that it looks like beef. The food additive is a strong insecticide that has no business being present in your digestive tract.