Things That Destroy Yogurt

Yogurt is enjoyed by many cultures.

Yogurt by definition is "a fermented, slightly acid, often flavored semisolid food made of milk and milk solids to which cultures of two bacteria (Lactobacillus bulgaricus and Streptococcus thermophilus) have been added." To destroy yogurt means killing the bacteria, rendering the yogurt inert or non-active. There are several influences that will affect yogurt.

Enzymes

Enzymes have the ability to change the chemical nature of proteins, including those found in yogurt. Part of digestion is when enzymes in the gastrointestinal tract break down proteins in the yogurt, changing them into different amino acids useful for the body. Enzymes such as those found in pineapple will do the same thing to fresh yogurt if allowed to stand for some time.

Heat

Heat will kill off the beneficial bacteria that form the culture that makes yogurt from milk. Heat the yogurt to 200 degrees and it will liquefy and curdle. Any bacteria involved in the mix will be killed and the structure of the proteins will change.

Antibiotics

Antibiotics will act the same way as the heat, killing off the bacteria and rendering the yogurt inactive. The structure of the yogurt will slowly liquefy as the acidity increases and the protein structures unravel. The two strains of bacteria common to yogurt, Lactobacillus bulgaricus and Streptococcus thermophilus, are sensitive to most common forms of antibiotics except for neomycin and polymyxin B.

Dehydration

Dehydration will not kill the bacteria in yogurt but it will slow down their reproduction and make them dormant until they are exposed to water again. Over time, the life of the dehydrated yogurt culture will deteriorate, lowering the count of viable bacteria.

References

• Cab Direct; Antibiotic Resistances of Yogurt Starter Cultures Streptococcus thermophilus and Lactobacillus bulgaricus; Suzzi; 1980
• Colorado State University; Nutrition Column - Yogurt: Choose Yours Live, Active and Probiotic: Pat Kendall, Ph.D., R.D.; Oct. 2005
• National Center for Food Preservation; Fermenting Yogurt at Home; Brian A. Nummer; Oct.. 2002
• Journal of Neuroscience Methods; A New Approach to Neural Cell Culture for Long-Term Studies; Steve Potter; March 2001