An establishment is deemed properly equipped for the cleansing and sterilization of bottles if it maintains and employs the following standards:

1. (a) Cleanses and sterilizes bottles by first soaking them in a hot caustic solution of not less than 120 degrees F. for a period of not less than five minutes which temperature shall be indicated by a thermometer. The solution shall contain not less than 2 1/2 percent of caustic soda expressed in terms of sodium hydrates.
2. (b) Changes the cleansing solution frequently so as to prevent its becoming foul and insanitary.
3. (c) Thoroughly rinses the bottles after the soaking.