Direct microbial counting method
1. Dilution
Dilute the suspension of brewing yeast appropriately. If the bacterial solution is not concentrated, it does not need to be diluted.
2. Mirror inspection counting room
Before adding samples, conduct a microscopic examination of the counting chamber of the counting board. If there is dirt, it needs to be cleaned before counting.
3. Add samples
Cover the clean and dry blood cell counting plate with a cover glass, and then use a sterile fine mouthed dropper to drop a small droplet (not too much) of diluted brewing yeast liquid from the edge of the cover glass, allowing the bacterial liquid to enter the counting room through capillary permeation along the gap. Generally, the counting room can be filled with bacterial liquid. Be careful not to produce bubbles.
4. Microscope counting
After standing still for 5 minutes, place the blood cell counting plate on the microscope stage, first use a low-power microscope to locate the counting chamber, and then switch to a high-power microscope for counting. If the bacterial solution is found to be too concentrated or too dilute before counting, the dilution should be readjusted before counting. The general sample dilution requirement is about 5-10 bacterial cells per small grid. Select 5 cells from each counting room (optional 4 corners and central cells) for counting. The bacterial cells located on the grid line are generally only counted on the upper and right lines. When yeast sprouts and the size of the bud reaches half of the mother cell, two bacterial counts are taken. Counting a sample requires obtaining values from two counting chambers to calculate the bacterial content of the sample.
5. Clean the hemocytometer
After use, rinse the hemocytometer with a water column on the faucet. Do not wash with hard objects. After washing, air dry or blow dry with a hair dryer. Microscopic examination, observe whether there are residual bacteria or other sediment in each small cell. If it is not clean, it must be washed repeatedly until it is clean.
