1. Fill a mason jar half-full with tepid water. Put it on the hotplate and raise the temperature to 98 degrees. Make sure you can keep it at this temperature for several hours. 2. Wash your hands. Cover the surfaces adjacent to your kitchen stove with paper towels. Place the test tube racks close to the stove on the paper towels.
3. Fill the pot with water and bring to a boil. Uncap your test tubes. Using your kitchen tongs, carefully drop your graduated cylinder, test tubes and their caps in boiling water. Boil for one minute.
4. Remove your test tubes and graduated cylinder from the water. Place the test tubes in the test tube rack.
5. Measure 9 ml of refrigerated pasteurized milk in the graduated cylinder. Pour 9 ml raw milk into each test tube
6. Using your calibrated eyedropper, measure 1 ml methylene blue. Place the methylene blue in one of the test tubes. …show more content…
Using the kitchen tongs remove the test tube caps from the pot, and cap the test tubes. The test tube with the methylene blue is your test sample. The test tube without the methylene blue is your control. Label each test tube.
8. Pick up your test tube and gentle shake them so that the methylene blue is dissolved. 9. Place each test tube in the water bath.
10. Examine the test tubes every 15 minutes for two hours and every hour afterwards.
Record your observations. If it takes more than 8 hours for the milk to turn white again, the quality of the raw milk is excellent. If it takes 5.5 to 8 hours for the raw milk to turn white, then there are less than 0.5 million organisms/ml of milk. If it takes 2 to 5.5 hours for the refrigerated pasteurized milk to regain color, then there are 0.5 to 4 million organisms/ml of refrigerated pasteurized milk. If it takes 20 minutes to 2 hours, then there are 4 to 20 million organisms/ml of refrigerated pasteurized milk. If it takes less than 20 minutes, then there are over 20 million organisms/ml.
11. Repeat steps using organic milk and then soy
3. Fill the pot with water and bring to a boil. Uncap your test tubes. Using your kitchen tongs, carefully drop your graduated cylinder, test tubes and their caps in boiling water. Boil for one minute.
4. Remove your test tubes and graduated cylinder from the water. Place the test tubes in the test tube rack.
5. Measure 9 ml of refrigerated pasteurized milk in the graduated cylinder. Pour 9 ml raw milk into each test tube
6. Using your calibrated eyedropper, measure 1 ml methylene blue. Place the methylene blue in one of the test tubes. …show more content…
Using the kitchen tongs remove the test tube caps from the pot, and cap the test tubes. The test tube with the methylene blue is your test sample. The test tube without the methylene blue is your control. Label each test tube.
8. Pick up your test tube and gentle shake them so that the methylene blue is dissolved. 9. Place each test tube in the water bath.
10. Examine the test tubes every 15 minutes for two hours and every hour afterwards.
Record your observations. If it takes more than 8 hours for the milk to turn white again, the quality of the raw milk is excellent. If it takes 5.5 to 8 hours for the raw milk to turn white, then there are less than 0.5 million organisms/ml of milk. If it takes 2 to 5.5 hours for the refrigerated pasteurized milk to regain color, then there are 0.5 to 4 million organisms/ml of refrigerated pasteurized milk. If it takes 20 minutes to 2 hours, then there are 4 to 20 million organisms/ml of refrigerated pasteurized milk. If it takes less than 20 minutes, then there are over 20 million organisms/ml.
11. Repeat steps using organic milk and then soy