Monday, April 20, 2009

Pasteurization vs Sterilization

Today I learned the difference (wikipedia):
Unlike sterilization, pasteurization is not intended to kill all pathogenic micro-organisms in the food or liquid. Instead, pasteurization aims to reduce the number of viable pathogens so they are unlikely to cause disease (assuming the pasteurization product is refrigerated and consumed before its expiration date). Commercial-scale sterilization of food is not common because it adversely affects the taste and quality of the product. Certain food products are processed to achieve the state of Commercial sterility.

Pasteurization typically uses temperatures below boiling since at temperatures above the boiling point for milk, casein micelles will irreversibly aggregate (or "curdle").

Bonus 1: Cloning ants
Mycocepurus smithii is the first known ant species to consist exclusively of females and to reproduce asexually. The species, which lives in South America, reproduces by cloning—all ants in a colony are clones of the queen.

Bonus 2: Cloned camel:
Injaz (Arabic: إنجاز‎, meaning "achievement"; born April 8, 2009) is a female dromedary camel, credited with being the world's first cloned camel.

Bonus 3: Ageing (Senescence)
Lately the role of telomeres in cellular senescence has aroused general interest, especially with a view to the possible genetically adverse effects of cloning. The successive shortening of the chromosomal telomeres with each cell cycle is also believed to limit the number of divisions of the cell, thus contributing to aging. There have, on the other hand, also been reports that cloning could alter the shortening of telomeres.

Cancer cells are usually immortal. This evasion of cellular senescence is the result, in about 85% of tumors, of up-activation of their telomerase genes. This simple observation suggests that reactivation of telomerases in healthy individuals could greatly increase their cancer risk.

Whether cell senescence plays any role in organismal aging is at present unknown, and is an active area of investigation.

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