chemistry science fair project (yogurt and yeast)

[bombae09]

my question is; can yogurt effect yeast growth? i appreciate all the help i can get on this topic thanks

[Louise]

my question is; can yogurt effect yeast growth? i appreciate all the help i can get on this topic thanks

This is more of a life sciences question than a physical science question. You should ask over there. However, you need to include the following information... what kind of yeast and what kind of yogurt? Is this an experiment you are going to do with yogurt from the store or baking yeast or what?

Some yogurt has "live cultures" and others have dead cultures of bacteria. Some have added sugar and fruit and flavors. There are also many different kinds of yeast... baking yeast, brewers yeast, nutirtional yeast, etc. [Yeast are fungi.] Each of these factors will influence whether there is an effect on yeast growth.

From a scientific paper I found, it says "Yogurts purchased from retail outlets were examined for the presence of yeasts by being plated onto oxytetracycline malt extract agar. Of the 128 samples examined, 45% exhibited yeast counts above 103 cells per g. A total of 73 yeast strains" [1]

So, at least 73 types of yeast grow in yogurt. Some yeasts might not grow in yogurt.

Louise


[1] The paper abstract I took this from is (this is a very technical paper written by Professors, so it may be too hard for you. However, it is a scientific study on this exact topic)-

Occurrence and Growth of Yeasts in Yogurts
V. R. Suriyarachchi and G. H. Fleet
Appl Environ Microbiol. 1981 October; 42(4): 574-579