29. (1) In any prosecution under this Act, it shall be no defence to allege-(a) that the accused was ignorant of the nature, substance or quality of the food; or(b) that the purchaser having purchased only for purposes of analysis was not prejudiced. (2) The seller shall not be deemed to have committed an offence under this Act if he proves-(a) that the food sold was purchased or obtained as agent by him with written warranty to the effect that it was of the same nature, substance or quality as that demanded by the purchaser;(b) that at the time he sold it he had no reason to believe that the food was not of such nature, substance or quality as that demanded by the purchaser; and(c) that he sold it in the same state in which he had purchased it. (3) No evidence of a warranty under clause (a) of sub-section (2) shall be admissible on behalf of the seller unless-(a) the seller has, within seven days of the service of the summons upon him, sent to the Inspector a copy of the warranty with a notice stating that he intends to rely on it and specifying the name and address of the person from whom he received it and has also sent a like notice of his intention to that person; and(b) such warranty is given by person permanently residing or carrying on business in ¹[Bangladesh]. (4) The Court shall summon the warrantor as a co-accused if it admits the warranty on behalf of the seller.