Prohibition of sale of unsound food

In any prosecution under sub-section (1), the court shall, unless and until the contrary is proved, presume— (a) that any animal found in the possession of a person who is in the habit of keeping animals of that class for sale for human consumption has been kept by such person for sale; and (b) that any food or drug found in the possession of a person who is in the habit of keeping, storing, manufacturing or preparing such food or drug for sale for human consumption, has been kept, stored, manufactured or prepared by such person for sale.