Where a person procures a sample consisting of a food or substance contained in unopened containers, and the division into parts of the food or substance contained in those containers—
is not reasonably practicable, or
might affect the composition, or impede the proper analysis, of the contents,
the provisions of Part I of Schedule 7, or of section 83, as the case may be, with respect to the division of samples into parts shall be deemed to be complied with if the person procuring the sample divides the containers into the requisite number of lots and deals with each lot as if it were a part in the manner provided by those provisions; and references in this Act to a part of a sample shall be construed accordingly.