On Fri, 8 Dec 1995, Sa'ad Al-Omari wrote:
> Can Ascaris lumbricoides eggs withstand boiling and remain viable?
>
Aha ! someone knows how to attract my attention. The simple answer is no,
they can't. The major permeability barrier (with respect to water soluble
materials) in Ascaris eggs is the internal lipid or ascaroside layer. The
free ascarosides which make up this structure melt at around 80-90 C, so
theoretically, if one can guarantee even distribution of heat throughout
whatever it is you're boiling, the ascaroside layer is disrupted and the
egg is freely permeable to water. Assuming the embryo also survives the
heat treatment, it won't survive the resultant loss of water. Some
interesting historical papers on the subject :
Ogata (1925) Ann. Trop. Med. Parasit. 19, 301-304
- eggs killed within seconds at 60-70 C
Manalang (1927) Philip. J. Sci. 33, 249-257
- significant drop in vitality after 5 minutes at 55 C
Anything by Fouquey, et al (eg. 1957) Bull. Soc. Chim. Biol. 39, 101-132
- on the physical and chemical properties of the ascarosides
Tarr and Schnoes (1973) Arch. Biochem. Biophys. 158, 288-296
- for a revised chemical structure
best,
Peter Darben
School of Life Science
Queensland University of Technology,
Brisbane, Q4000,
Australia
"No longer making the world safe from pig worms - you're on your own now
folks"
