Sweet Preservative: Newsletter Challenge (September 2012)

The sugar is so sweet it makes the bacteria sick and so they stay away.

It doesn't seem to keep molds away though, judging by a half-used jar of jam I just threw away.

Sugar is an electrolite just like salt and thus being capable of preventing bacterial attack.

The other important point is that being reducing type oxygen is deprived for bacterial survival as well as curtailing the reproduction of bacterial families.

The reduction based glucose present in sugar, work as an anti oxidant thus deprive oxygen for bacteria by hydrogen release.

Thank you for the micro biology based interpretation. It was worth learning.

Regards

S.Udhayamarthandan

Sugar is food for Candida Albicans, or it was the last time I sat through a microbiology lecture at uni. Maybe I missremembered that one. Mel Gibson could comment on this one. He was seriously ill in the mid eighties from a systemic Candida Albicans infestation, which had been fed in his intestinal track by large quantities of pasta, and beer, and had spread to his lungs, or so the story goes according to the article that I read somewhere. A doctor in Sydney told a friend of mine, during the recent flu season, that a good course of action is to gargle salty water. The salt lyses the cellular structure of the throat strep and related viral and bacteriological cronies. It got me thinking, if you have candida of the stomach, or suspect other nasty bugs in the intestinal tract, would the odd dose of salt with meals not go astray. I know this is dangerous ground from an arterial schlerotic point of view, but if you are elderly (ish?) a big respiratory tract infection can finish you off. It is the most common cause of death in the elderly, not heart attacks, strokes, or other cardio vascular conditions. Discuss

This is a simple one. And it is a nonspecific preservative process. Nonspecific in a sense, that it stops any and all microorganisms.

The cells in your body and in microorganisms function with salt concentration roughly that of the oceans. Anything, that upsets that degrades, then stops the cell from functioning. Too much salt or sugar does that to the invading microorganisms, as the concentrations seek equilibrium. That sucks water out from the inside of the cells. They stop: preservation.

Osmosis

I am Diabetic Type I. I have to avoid sugar, so how I can benefit from such qualities of sugar?.

Its a common misconception that Type 1 diabetics MUST avoid sugar. They must simply balance sugar intake with the proper amount of insulin.

For most diabetics, its just simpler and easier to avoid/limit processed sugar, its not a 'must do' sort of thing.

Honestly? I don't know. I make my jam with the least sugar possible since we like it a bit sour. Recently I added a shot of Rum to the jam, which makes everyone addictive. Now and here we come how we preserve the jam in the first place:

We eat it!

Thanks sugar but no sugar

The sugar works in the same way in jam as it does in honey. The sugar content is so high that water is drawn out of the bacterium cell (by osmosis as noted by Rixter) causing it to "implode". It's the reason honey doesn't go off, as explained in recent BBC Radio 4 programme (The Food Prgramme, I think; details should still be available on their webpage); it's also the reason why honey is a good field antiseptic (hold in place with clean, fresh cobwebs. Really.)

I'm guessing that the mould only grows on the surface of the jam where the atmopheric water has diluted the sugar concentrate somewhat. I've noticed that moulds usually start either on the scraps of jam on the jar walls, or in the "puddles" that always form on the surface of opened jam. Then there's the curse of "low-cal" jam, sugar substitutes and the long term effectiveness of preservatives. Funny, but my mum's homemade jam could last for several years; even opened, it could stay untainted for six months. I always found 2 or 3 year old gooseberry jam far nicer than the year old stuff. I suspected an amount of fermentation, but how would the yeast survive?

Like honey, you can use sugar as an antiseptic for wounds. Also, my grandmother swore by sugar as a cleanser for face, hands, elbows and feet before going to bed each night. It acts as a gentle abrasive to keep your skin soft and wrinkle free.

Oh yes indeedy! My favourite shower scrub is a mixture of sugar and almond kernal shells (the latter being ground up). Leaves me feely sparkly!!

No water?

Hang on..you're English. Right you are then....

Crusty.

It increases osmotic pressure/decreases water activity so bacteria cannot grow. Botulism is an anaerobe, and canned goods are susceptible. Lack of oxygen is another requirement for botulism to grow, as is the correct pH range-

Until recently it was thought that proteins could only exist and function in an aqueous environment; that idea was overturned by the discovery that some proteins could unfold and refold to regain activity in the absence of water. The preservative action of sugar (and salt) is largely due to the reduction in available water (or water activity) and hence the inactivation of proteins including enzymes; plus the lack of water to act as solvent to allow the passage of nutrients into the cell and the excretion of waste products in the case of bacteria.

Easy & simple. The sugar raises the boiling point of the preserve above the temperature required to kill the botulism spores and/or toxins!

bacteria need a moisture environment to alive; the sugar is a boundig agent to the water so the bacteria cannot survive by the missing water!

(maybe the sugar changes to alcohol?

Bacteria can only grow by ingesting water borne nutrients. Jams and Jellies have a very high sugar content. The sugar disolves in the water and changes the properties of the water which renders it useless to bacteria.

Welllll... The answer is... When you boil the jam it kills the bacteria.. When you put the sugar in the jam it is what prevents the re-growth of the bacteria because that bacteria can not grow in a sugar environment. Sugar also promotes the growth of beneficial bacteria like Lactobacillus by feeding them.

How is this a 'challenge', guys?

It's not puzzle that requires thinking something through and coming up with solutions, and it's not something you can answer short of having access to a biochem lab, so what's the challenge?

Who can Google the answer first?

Doesn't "dragging tiny bits of questionably relevant or anecdotal data from my ancient brain" count as a challenge?

Good point. Or, how's about "Can you login to CR4?" [ssshhh]