Preview

Food Microbiology Lab

Satisfactory Essays
Open Document
Open Document
535 Words
Grammar
Grammar
Plagiarism
Plagiarism
Writing
Writing
Score
Score
Food Microbiology Lab
Determining pH Using a Red Cabbage

Farnoosh Mazarei

Food Microbiology

April 22, 2011

Purpose: To test the pH level of many common household object by use of the juice from a red cabbage.

Background: pH is the measure of the acidity or basicity of a solution. The pH scale ranges from 1 to 14 with 1 through 6 being acidic and 8 through 14 being basic; 7 is considered neutral. The use of the red cabbage, or red cabbage juice is because red cabbage can be used as an acid/base indicator. The pH level of foods is important to food microbiology because having proper pH levels can prevent food borne illness. This is of extreme importance when it comes to canning of foods in particular. Many home canned foods can be a breading ground
…show more content…
To make an acid-base indicator, extract juice from red cabbage. First, cut up some red cabbage and place it in a large pot. Add enough water so that the pot is half full. Then bring the mixture to a boil. Let it cool, and pour off the cabbage juice. Save the solution. 2. Assemble food, beverages, and cleaning products to be tested. 3. If the substance being tested is a liquid, pour about 5 mL into a small beaker. If it is a solid, place a small amount into a beaker and moisten it with about 5 mL of water. 4. Add a drop or two of the red cabbage juice to the solution being tested, and note the color. The solution will turn red if it is acidic and green if it is basic.

Data:

|Solution |Result |
|Dishwashing Liquid |Basic |
|Dishwashing Detergent |N/A

You May Also Find These Documents Helpful

  • Good Essays

    Chm 130 Lab 12

    • 1003 Words
    • 6 Pages

    In this experiment the student will need a Bunsen burner, ring stand, wire gauze, pH meter, red cabbage, about seven small beakers (clean), seven test tubes, universal pH paper, both red and blue litmus paper, methyl red and several solutions provided by the instructor. First the student will prepare the red cabbage by filling a beaker with 50 mL of distilled water and placing about 1 gram of finely chopped red cabbage and boil for 10 minuets. Let the beaker cool and decant the solution from the cabbage. While the cabbage is boiling the student should continue with the rest of the experiment, pour about 2 mL into the beaker and test the pH with the pH meter, litmus papers, and universal pH paper and record. Pour half of the solution into a test tube and set aside. With the sample in the beaker add 2 drops of methyl red and record. With the solution in the test tube add a dropper full of the cabbage indicator and record. The student must do these steps with all of the solution provided for in this experiment.…

    • 1003 Words
    • 6 Pages
    Good Essays
  • Better Essays

    Class Action Lab Report

    • 1112 Words
    • 5 Pages

    Test the solution with the litmus papers (red and blue) by dropping a small amount of the solution onto the paper with the stirring rod.…

    • 1112 Words
    • 5 Pages
    Better Essays
  • Satisfactory Essays

    Lab 4 Weak Acid Unknown

    • 304 Words
    • 2 Pages

    When testing the acid, use only between 0.2 g and 0.3 g for each trial (get as precise a measurement as you can). The general procedure is to weigh out your acid, dissolve it in water, add a couple drops of the indicator (phenolphthalein), and then add the sodium hydroxide until you note a color change (from clear to pink). When the color change occurs, you have added enough base to completely react with the acid (the endpoint). You are allowed three trials, and will be graded on accuracy.…

    • 304 Words
    • 2 Pages
    Satisfactory Essays
  • Satisfactory Essays

    Lab002exp0011

    • 577 Words
    • 3 Pages

    6. Use the litmus test strips to determine if the substances in weigh boats A - C are acidic or basic. This is accomplished by briefly dipping an unused strip of the litmus paper in each of the weigh boats. Record your color results in Table 2.…

    • 577 Words
    • 3 Pages
    Satisfactory Essays
  • Good Essays

    Scheme of Analysis #5

    • 608 Words
    • 3 Pages

    -In a small test tube/vial, or spot plate and place 10-15 drops of solution to test…

    • 608 Words
    • 3 Pages
    Good Essays
  • Satisfactory Essays

    Coffee Filter Lab

    • 619 Words
    • 3 Pages

    With tongs or a fork, remove and discard as many cabbage pieces from the container as you can. 4. Carefully pour the remaining cabbage water from the larger container through the coffee filter into the three smaller cups or other transparent containers. 5. Note the purplish or dark blue color. If the cabbage water has a pH of about 7.0, which is typical for plain tap water, the color will be more purplish. If your water is treated by a water supply facility, it may have a pH around 8.0, resulting in a dark blue color. This water color is your baseline. You will be comparing other colors to this as you proceed. 6. Use a drinking straw or eyedropper to transfer vinegar from its container to one cup of cabbage water, five drops at a time. Stir the cabbage water after each vinegar transfer. Note any color change. Continue transferring vinegar five drops at a time until the color of the cabbage water has changed to a color different from that of the original cabbage water. 7. Use a craft stick or toothpick to transfer baking soda from its container to another cup of cabbage water, just a few grains at a time. Stir the cabbage water after each baking soda transfer. Note any color change. Continue transferring baking soda a few grains at a time until the color of the cabbage water has changed to a color different from that of the original cabbage water. 8. The THIRD cup is your baseline cup. If you tap water is neutral, its color should be mostly purple, but it may be more bluish if your tap water has been treated by your county or city water supplier. 9. Record the color of the water after your final additions of vinegar or baking soda. What pH does each color represent? Is vinegar an acid or a base? How about baking…

    • 619 Words
    • 3 Pages
    Satisfactory Essays
  • Satisfactory Essays

    Acid & Base Lab

    • 607 Words
    • 3 Pages

    Test the pH of the Unknown substances with litmus paper and pH indicator paper and match to color chart…

    • 607 Words
    • 3 Pages
    Satisfactory Essays
  • Good Essays

    i. Add excess of 6 M HNO3 drops to a sample of your unknown until solution turns acidic. Use blue litmus paper to see when it turns red. Then add excess of .02 M AgNO3.…

    • 889 Words
    • 4 Pages
    Good Essays
  • Good Essays

    INT Task 3

    • 1084 Words
    • 5 Pages

    The pH scale is a method of telling how acidic or basic solutions are in reference to something neutral like water. The range for the scale is 0-14. If something has a pH value of 0, it is extremely acidic, while the opposite is if something is a 14 it is extremely basic. Pure water has a pH of 7 and is very neutral. Either extreme can be harmful to humans.…

    • 1084 Words
    • 5 Pages
    Good Essays
  • Good Essays

    labeled test tubes. Take two more small labeled test tubes and place 4 or 5 drops of your…

    • 1385 Words
    • 6 Pages
    Good Essays
  • Good Essays

    Transforming Copper

    • 565 Words
    • 3 Pages

    We will use red litmus paper, an acid base indicator that is red in acidic solution and…

    • 565 Words
    • 3 Pages
    Good Essays
  • Satisfactory Essays

    lab and ph

    • 543 Words
    • 3 Pages

    In this lab, of pH and Chromatography, in the pH aspect of the lab we are trying to figure out the pH level of certain chemicals by writing down of known solutions to find the type of unkown solution using pH standards. In the Chromatography, we are trying to separate the chemicals using water and a piece of paper.…

    • 543 Words
    • 3 Pages
    Satisfactory Essays
  • Good Essays

    Experiment 2

    • 864 Words
    • 4 Pages

    The results of adding the blue indicator was a color change. It turned orange, indicating acidity.…

    • 864 Words
    • 4 Pages
    Good Essays
  • Good Essays

    Acid Lab

    • 439 Words
    • 2 Pages

    In addition the indicators that were the most accurate were the pH paper and the phenalthalein. The phenalthalien was one of the most accurate indicators because the bright magenta pink color that a base substance turned was very prominent compared to the clear color that formed when the substance was an acid. The pH paper was the most accurate indicator because there was a color chart that showed specifically whether or not the substance was a base or an acid. The pH paper also got detailed enough to show whether or not the substance was pure/neutral or a strong base or acid. Furthermore, it was easy to tell that acids were 1-6 on the pH scale, water or neutral substances were 7, and bases were from 8- 14. The other indicators were not as accurate. The indicator phenol red always turned the substance either a yellow orange color or a red orange color, and that was sometimes a little difficult to figure out whether or not a substance was a base or an acid. The bronthymol blue did turn a yellow color in the presence of an acid, but sometimes the substance either turned a greenish color or had specks of blue in the substance. When the substance was tested in both the red and the blue litmus papers sometimes there were contradictory results, so the litmus paper…

    • 439 Words
    • 2 Pages
    Good Essays
  • Satisfactory Essays

    To figure out the results, the Universal Indicator was used in order to help indicate what pH level the cabbage indicator was, for a specific colour. The colour range for the Universal Indicator from the experiment matched closely with the scale on the internet (Understanding Body pH Balance. (2012, January 07). Retrieved November 14, 2017, from https://docakilah.wordpress.com/2011/11/29/understanding-body-ph-balance/). It went from red, to green/yellow, then deep purple (pH 1, pH 7, pH 14). For the colour range of the red cabbage indicator, it went from red, to light purple, to bright yellow (pH 1, pH 7, pH 14). The Universal Indicator’s colour range seems common and similar to many other scales. A few examples are the red litmus paper,…

    • 220 Words
    • 1 Page
    Satisfactory Essays