Scientists have stumbled on a basic property of preservatives that might extend the shelf life of vaccines, food and library books - and save money while doing it.
Besides jams, sugars are often used to preserve pharmaceuticals and similar biological materials. There are a number of mechanisms involved, but recently the local stiffening of the preservative was identified as a factor that can increase shelf life.
Basically, stiffening decreases 'rattling' of the fluid's molecules and stabilises the product, because these motions are intimately involved in spoiling - for instance, in the protein degradation processes that lead to the loss of biological function.
Several years ago, the National Institute of Standards and Technology (NIST) team discovered the practical importance of high-frequency molecular rattling for protein preservation.
But while sugars and other preservatives such as salts have been used since ancient times, the prediction of how well a preservative works for a specific material has remained more an art than a science, said a NIST release.
However, the NIST method "should remove much of the guesswork in determining the best way to protect a particular commodity," said Jack Douglas of Polymers Division, NIST.