a BPB, Butterfield's phosphate buffer (pH 7.2); BPBT, Butterfield's phosphate broth + 1% Tween 80; BPW, buffered peptone water; NB, neutralizing broth; PBS, phosphate-buffered saline (pH 7.2); PW, peptone water (0.1%); PWS, peptone water (0.1%) + 0.85% sodium chloride; PWT, peptone water (0.1%) + 1% Tween 80.
The performance of recovery media for supporting colony development was also evaluated. The composition of diluents had little effect on the number of yeasts and molds recovered from fruits. Dichloran rose bengal chloramphe-nicol agar and plate count agar supplemented with chloramphenicol were equivalent in supporting colony formation. A study to determine the effect of diluent composition on recovery of yeasts from grape juice and passion fruit pulp showed that dilution in 0.1% peptone gave higher counts compared to dilution in distilled water, saline, or phosphate buffers .
Media selective for yeasts and molds found on raw fruits and vegetables, as well as other types of foods, have been reviewed [36,41]. Formulations have been developed to select for acid-resistant yeasts and detection of proteo-lytic and lipolytic enzyme activity. Media for detecting mycotoxigenic molds and selecting for xerophilic and xerotolerant fungi have been developed. Release of tissue juices from produce, particularly those with high sugar content, followed by drying on the produce surface can result in reduced water activity that is selective for these yeasts and molds. Some considerations when analyzing produce and other foods for the presence of xerophilic fungi are recommended by Beuchat and Hocking .
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