Dip Slides are used to determine the total aerobic microbial contamination in aqueous (water) samples or on surfaces. Using them on non aqueous samples such as fuel or oil will lead to erratic results at best.
Dip Slides consists of a plastic slide carrying two different nutritive agar gels on opposite sides of the slide. One side has been designed to culture bacteria which grow as visible discrete red colonies when the slide is incubated for a few days. The other side of the slide will culture moulds (fuzzy or fluffy colonies) and yeast’s (usually white, cream or pink round colonies). The slide is dipped into the fluid to be tested or pressed against a surface, and then incubated. The slide appearance is compared to calibration charts.