It is unlawful for any dealer or retail store to sell milk for fluid consumption at less than the cost thereof to the dealer or retail store with the purpose or intent to injure competitors or destroy competition. In all proceedings brought to enforce this section, proof of consistent and repeated advertisements, offers to sell or sales of milk for fluid consumption by any dealer or retail store at less than cost to them, as defined in sections 2984 and 2985, the advertisements, offers to sell and sales thereby forming a pattern of sales below cost, shall be prima facie evidence of intent to injure competitors and destroy competition. This section shall not apply where the price of milk for fluid consumption is set in good faith to meet legal competition. [PL 1983, c. 484, §2 (NEW).]