Most people would think bacteria in or on food can only be harmful.
True, food poisoning caused by bacteria and their products is a serious
problem, and how to ensure food
safety is treated in a different exhibit. However, certain bacteria
are safe in food, and are required for the desired taste and texture. This
exhibit describes some of the applications of bacteria and their products
in the food industry.
Bacteria are commonly used in dairy products. Sour cream and Creme fresh (make your own! Creme fresh (Source: Splendid Table) are both the products of cream after bacteria were allowed to grow in it. The difference in flavour,
texture, and behavior (sour cream will curdle when heated, creme fresh
will not) all result from the differences in bacteria required to produce
the two products. Buttermilk
(Source: DB Frankhauser) is low in fat, cheese
comes many variations (Source: Franceway.com). Yogurt (Source:
Life.ca) is probably one of the oldest forms of fermented milk.
Is it not dangerous to eat
food containing bacteria? Certainly not, as long as they are the right
kind of bugs. It may even be benificial
to eat diary products with living cultures, although the evidence is
still controversial (Source: NewYork Times Sciene Q&A).
True or not, fermented milk products are often suitable
for people with a lactose intolerance (Source: Regional Health Science Center)
though the product should not be heated after fermentation.
Fermented milk products
are not completely fluid because casein,
the major protein in milk, is insoluble in acid (Source:
DB Frankhauser). Casein is also the protein that makes cheese solid.
Fermented diary products taste different due to the bacteria used to make them.
So what kind of bacteria are used for these foods? Most manufacturers
will not release their magical strain of bacteria, producing just the right
flavour, but here are their general characteristics:
Have you ever thought that bacteria were used to produce chocolate and coffee? Although bacteria are not present in the final products containing chocolate (Source: ScienceNews online), yeasts and bacteria degrade the pulp that covers fresh chocolate beans (Source: CL Case) Did you know that chocolate may not be bad for you in contrast to what your mother made you believe? (Source: Manbir-Online).
Another example of bacteria helping to produce food products is vinegar. Whether good or bad depends on what the product should be. Wine makers will do their best to inhibit Acetobacter ferminting their grape juice: in order to produce wine, yeast should grow but not bacteria. However, if the desired product is vinegar, bacteria have their chance. Read more about wine and vinegar making in our special feature file.
Fermenting bacteria are used in the production of sausage. Again, lactic acid bacteria do their job. All you want to know about sausage (Source: The Cook's Thesaurusi). Don't worry, you can still enjoy your meat snacks (Source:FoodProductDesign) since bacteria used in sausages are not at all related to E. coli or Salmonella, the enemy of every butcher. In fact, lactic acid bacteria are able to kill Listeria, a newly discovered ability that supports the safety of cured meats (Source: INRA).
And, finally, if you want to be active yourself, get started!
The content of this page is copyright of the Virtual Museum of Bacteria and was written by Dr. T. M. Wassenaar (curator), with support of the Foundation for Bacteriology.
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Page last modified: 09 Mar 2007
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