Use of Sublimation To Prepare Solid Microbial Media with Water-Insoluble Substrates

ABSTRACT A method was developed to deposit a visible layer of water-insoluble compounds via sublimation onto the surface of solid media. The compound is sublimed from a heated aluminum dish containing the compound onto the surface of an inverted, ice-cooled, inoculated agar petri dish. The method results in the deposition of a thin, even layer on the agar surface without the use of solvent. After incubation, clearing zones around colonies indicate the presence of compound-degrading microorganisms.

Total Solids in Oysters

Preliminary work is underway on studies of two methods for determining total solids in oysters: (a) the Radarange in conjunction with the forced draft oven, and (b) the Ohaus moisture determination balance. The results obtained by each method are compared directly with the official AOAC procedure. A 10 g sample is weighed into a Pyrex petri dish, exposed in the Radarange 4 minutes, and then placed in a forced draft oven set at 100°C for 20 minutes at full draft. The Ohaus moisture determination balance was calibrated to utilize a 9 cm diameter aluminum dish. The sample is weighed directly on the balance, and the heater is lowered over the sample long enough to dry the sample. This method is rapid (approximately 10 minutes), but only one sample may be determined at one time. Studies will be continued.