No slaughterer shall have any package of horse meat ready for distribution in its possession unless such package is plainly labeled as is provided by Section 9 of this Act. The possession or control of any horse meat which violates any of the provisions of this Act shall be held to be prima facie evidence that such possession or control is or was with intent to sell or use such horse meat in violation of this Act. Whoever shall have possession or control with intent to sell any horse meat which violates any of the provisions of this Act shall be held to have known the true character, quality and name of such horse meat.