For new comers in China often face a problem to recognize halal food. In Chinese halal is known as 清真 (Qīngzhèn). So in every halal food/product you would see this word on the label and that's how you will be able to recognize either the food/product is halal or not.
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Recognize Halal food/product in China
Sometime it is difficult for non-Chinese to recognize halal food. The link given below will give a clear idea about how to recognize halal food/product in China.
bdcomcn.com/index.php/halal-food/Halal-Food-in-China.html