How does sugar act as a preservative?

Thursday 18th November 2010
Submitted by Divya Sehgal
ANON

Bacteria evolved in environments where the concentration of sugars and salts is the same as or lower than those inside the cell. High sugar concentrations cause the bacterium to lose water by osmosis and it doesn’t have any cellular machinery to pump it back in against the osmotic gradient. Without enough water, the bacteria can’t grow or divide. Mould is more tolerant though and can grow on some jams.

GOT A QUESTION?

Scratching your head over a burning scientific conundrum? submit your question and we'll get our esteemed panel of experts to answer it for you.

 

What were UV lights initially intended for?
previous qanda Article
How long do two groups have to be separated before they become different species?
next qanda Article
Q&A Tabs

Phlegm is the mucous secretion of the respiratory passages. The cilia cells that line these passages are continually driving the phlegm upward to the throat, where it triggers the swallow reflex...

Lobsters and other shellfish have harmful bacteria naturally present in their flesh. Once the lobster is dead, these bacteria can rapidly multiply and release toxins that may not be destroyed by...

All of it! Every neuron in the brain is continually active, even if firing only slowly. Neurons that stop responding die. Even so, many people seem to believe that we use only part of our brain....

The powder is actually tiny scales made from modified hairs. Moths, like butterflies, belong to the order Lepidoptera, which means 'scale wing'. The scales are pigmented but they also contribute...

Bees, like all insects, have six sections to their legs: the coxa, trochanter, femur, tibia, metatarsus and tarsus. Each is connected by a joint and the one most like a knee is between the femur...

All female mammals have a clitoris, the sole purpose of which is to react to sexual stimulation, and presumably this stimulation has evolved to be pleasurable for most species. But establishing...

To create a sound, we have to set matter - whether it's a gas like air, a liquid or even a solid material - in regular motion, creating a wave of specific frequencies, which we hear as a sound of...

Mirrors don’t reverse left and right either – that’s just our interpretation of what happens. Your reflection in the mirror is actually reversed front to back – if you have...

Discovered by an American student named Gary Flandro in the mid-1960s, the slingshot manoeuvre usually involves spacecraft briefly 'coat-tailing' a planet orbiting the Sun, extracting some of the...

The ice disappears because the wind blows away water molecules that have evaporated or 'sublimed' from the ice, so the ice slowly shrinks in size. The molecules that escape are those with the...