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Two Methods:Preparing the Culture DishGrowing the Acidophilus CultureCommunity Q&A

Lactobacillus acidophilus and related bacteria from the family Lactobacillae (Lactobacillus casei, Lactobacillus bulgaricus) are part of a group of organisms known as probiotics for their beneficial effects on the human body. Normally, acidophilus is found naturally in some foods, added to others, and available from nutritional stores as supplements in pill or powder form. However, it is possible to make acidophilus cultures by growing acidophilus in a petri dish; the following steps describe how to do so.


Method 1
Preparing the Culture Dish

  1. 1
    Prepare a solution of agar. Follow the directions given on the bottle.
  2. 2
    Pour the solution into a petri dish. Pour in enough agar solution to cover the bottom of the dish.
  3. 3
    Rotate the dish until the agar covers the bottom to an even depth.
  4. 4
    Cover the dish.
  5. 5
    Let the dish stand until the agar gels. The gelled agar should appear firm to the eye; if necessary, gently tip the dish to make sure the agar doesn't run.
  6. 6
    Turn the dish upside down. The agar should still cling to the dish.
  7. 7
    Refrigerate the dish until ready to grow your acidophilus culture.

Method 2
Growing the Acidophilus Culture

  1. 1
    Obtain a starter culture. You can use either a yogurt "starter" or an unflavored yogurt with live cultures (as indicated on the label) in it. You can find either at a grocery or health food store.
  2. 2
    Dip a sterile cotton swab into the starter culture.
  3. 3
    Uncover the culture dish.
  4. 4
    Rub the cotton swab over the agar gently. Rub the swab in a zigzag pattern to ensure the culture transfers from the swab to the agar. Cover the dish again after transferring the acidophilus culture to prevent contamination from other bacteria.
  5. 5
    Incubate the culture. Put the culture dish in an area where the temperature reaches 95 degrees Fahrenheit (35 degrees Celsius) for a period of 3 to 7 days, preferably in a dark area that won't be disturbed. You should be able to see new cultures form on the agar.

Community Q&A

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    • To see how environmental factors affect the growth of the acidophilus, make multiple culture dishes. You can test the effect of various chemicals, such as alcohol or household cleaner, on the culture dishes, leaving one dish unaffected as a "control" dish. You can also grow other bacterial cultures and demonstrate the effects of acidophilus on the other bacteria.
    • You can also grow the acidophilus culture in a small amount of skim milk, water, or soy broth.
    • To dispose of the acidophilus culture, add 1 tablespoon of bleach to the agar, cover the petri dish again, and seal it in a plastic bag. Then, throw it away.


    • The above instructions are intended for growing an acidophilus culture to observe how the bacterium grows. For safety's sake, do not use an acidophilus culture grown this way in making acidophilus milk or yogurt, particularly if you want to share the finished product with others.

    Things You'll Need

    • Petri dish
    • Acidophilus culture source/starter
    • Cotton swab
    • Agar or other nutrient/growth solution

    Article Info

    Categories: Yogurt

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