"that sugar is an excellent inhibitor of bacterial growth"
100% Ass Backwards, I'm afraid....We use sugared water to grow bacterial broths in the laboratory. Sugar is excellent encourager of bacterial growth.
What makes Jams and preserves keep for so long is the
high acidity which prevents baterial growth, as well as the aseptic conditions in which they were made: You have to boil AND sterilize jam jars religously before making them, then seal the tops with a wax disc AND a screwcap....Plus jams are boiled completely before jarring, which kills any bateria/ funghal spores in the jam itself.
If jams were resistant to bacteria then you wouldn't have to refridgerate them....
Most bacteria and funghi that spoil food need the following to survive:
1. Moisture or rather free/ available
liquid water(Hence Freeze dried foods last longest)
2. Sugar or Starch- for food.
3. The correct temperature range (Below 40oC and above 0oC- hence freezing for preservation and boiling for sterilisation)
4. The correct pH range (Fairly close to Neutral pH7 for most, though there are some that prefer more acid or more alkali)
below freezing- bacteria are dormant
Above 40oC and their proteins begin to scramble and they die
Remove the water and bacteria cannot carry out the chemical reactions they need to metabolise sugars and/or die from catastrophic osmotic shift.
Remove the sugar- no food to grow and multiply- some species die, others encyst to dormancy
Change the pH beyond the tolerance range of the species and again, at the cell membrane, chemical reactions and osmosis gradient are totally buggered up.
There are some resisitant little bugs that need 75oC+ to sterilise (Pyrlobacter in Yoghurt springs to mind) and some, non-food spoiling funghi make their own water to grow (Dry Rot or Lachrymans, which means "weeping" in Latin, makes a tiny drop of water at it's growth face to grow into)....but must all food spoiling bacteria are killled by over 75oC and made dormant by sub Zero conditions.
PS- this is from memory, not Google
