Preparation instructions are as follow:
Dissolve 26.5 g in 1 liter of purified water. Heat in boiling water and agitate frequently until completely dissolved. Do not autoclave, do not overheat!
Cool the medium to 45 - 50 °C and pour plates. According to EN ISO 9308-1 dispense in Petri dishes to a depth of at least 4 mm (approximately 18 ml in a 90 mm plate).
For using by poured plate method cool the medium to 44 - 47 °C in a water bath before use (see EN ISO 11133).
The prepared medium is slightly turbid to turbid and yellowish. The pH value at 25 °C is in the range of 6.6-7.0
There should be no visible moisture on the plates before use. When moisture is present, the plates should be dried for the minimum time required to remove visible moisture, following the procedure as described by EN ISO 11133.
Preparation and addition of optional Cefsulodin solution (US-EPA approved method): Dissolve 5 mg of Cefsulodin in 2 ml of purified water and sterilize by membrane filtration (0.2 μm nominal pore size). Aseptically add the solution (2 ml per 500 ml of medium) to 500 ml of liquefied medium (45 - 50 °C). Pour plates as described above.