In proceedings under this Part or the Regulations,

(a) a certificate of analysis signed by a public analyst shall be accepted as prima facie evidence of the facts stated in it;

(b) evidence that a package containing an article to which this Part or the Regulations apply bears a name, address or registered mark of the person by whom it was manufactured or packed is prima facie evidence that the article was manufactured or packed by that person;

(c) a substance commonly used for human or animal consumption shall, if sold, or offered or exposed for sale, be presumed until the contrary is proved, to have been sold or to be intended for sale for human or animal consumption;

(d) a substance commonly used for human or animal consumption which is found on premises used for the preparation or sale of that substance and a substance commonly used in the manufacture of products for animal consumption which is found on premises used for the preparation or sale of those products, shall be presumed until the contrary is proved, to be intended for sale or for manufacturing the products for sale for human or animal consumption.