(1) "Pasteurized beer" shall mean beer which has been subjected to such process or processes in manufacture and packaging that in all cases all yeast cells or other microorganisms are killed, inactivated, or removed, thereby preventing any further fermentation or microbiological decomposition of the packaged beer which might otherwise take place.

(2) In addition to the usual and customary meaning above, "pasteurized beer" shall include bottle conditioned beer which has been fermented partially or completely in the container and which may contain residual active yeast.

(3) A "gallon," when used in computing any tax, shall mean the United States standard gallon of 231 cubic inches.