# The Milk (Special Designation) Regulations 1988, Paragraph 2: Reagent – Methylene Blue


(1) Tablets manufactured under arrangements made by the Minister shall be used for the test. A solution shall be prepared aseptically by adding one tablet to 200 ml. of cold, sterile, glass-distilled water in a sterile flask, shaking until the tablet is completely dissolved, and making up the solution to 800 ml. with cold, sterile, glass-distilled water. The resultant solution shall be stored in a stoppered sterile flask in a cool, dark place, and shall not be used if–
(a) it has been exposed to sunlight, or
(b) a period of two months has elapsed since the date of preparation.
(2) The amount of methylene blue required for a day’s work shall be poured off from the stock bottle into a suitable glass container. The pipette used for transferring the methylene blue solution to the tubes of milk shall not be introduced into the stock bottle.

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Source: https://www.legislation.gov.uk/uksi/1988/2204/schedule/5/part/II/paragraph/2 (the official version)
Page: https://openlegislation.uk/milk-special-designation-regulations-1988/schedule-5/part-II/paragraph-2
Contains public sector information licensed under the Open Government Licence v3.0. Source: legislation.gov.uk, The National Archives.