http://reply.papertrans.cn/2/162/16135/16135-31.png
Submitted on: 20 March 2010.
Revised on: 12 July 2010.
Accepted on: 10 August 2010.
___________________Journal of Consumer Protection and Food Safety
http://reply.papertrans.cn/2/162/16135/16135-33.png
http://reply.papertrans.cn/2/162/16135/16135-34.png
http://reply.papertrans.cn/2/162/16135/16135-35.png
http://reply.papertrans.cn/2/162/16135/16135-36.png