A person may not sell canned food in a container which-
(a) bulges at the flat or round sides or ends or one side of which bulges when the other side is pressed;
(b) is in any way blown or from which gas escapes from the lid or from any part thereof when it is opened or punctured, unless-
(i) the container contains an aerated drink; or
(ii) gas has been used as a preservative.