Why Doesn't Sugar Rot? Bacteria & Tasty Treats

  • Thread starter Thread starter pikapika!
  • Start date Start date
  • Tags Tags
    Sugar
Click For Summary

Discussion Overview

The discussion revolves around the reasons why sugar does not decay and the implications for microbial growth, particularly focusing on the roles of water content and osmotic pressure. Participants explore the differences between sugar and other substances like agar and syrup in terms of their interactions with bacteria and fungi.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • Some participants suggest that dry sugar does not decay due to its low water content, which prevents organisms from growing on it.
  • Others note that while syrups can develop fungal mats, the high osmotic pressure from sugar limits most organisms, although fungi may tolerate it better.
  • One participant mentions that bacteria find sugar appealing but die upon contact due to the strong water absorption properties of sugar, which pulls water out of bacterial cells.
  • A participant clarifies that agar, used for growing microbes, is a sulfated polymer of galactose and lacks free simple sugars, serving as a support medium rather than a nutrient source.
  • Another participant simplifies the explanation by comparing sugar to salt, describing both as desiccants.
  • A later reply raises a speculative question about the potential for engineering a microbial pathogen to mimic the properties of standard growing mediums, suggesting it could evade detection.

Areas of Agreement / Disagreement

Participants express varying views on the mechanisms behind sugar's resistance to decay and the implications for microbial growth. There is no consensus on the effectiveness of different substances or the feasibility of engineering pathogens.

Contextual Notes

Some assumptions about microbial behavior and the properties of different substances remain unexamined, and the discussion does not resolve the complexities of osmotic pressure or the specifics of microbial growth conditions.

Who May Find This Useful

This discussion may be of interest to those studying microbiology, food science, or anyone curious about the interactions between microorganisms and various substrates.

pikapika!
Messages
28
Reaction score
0
So what does it take for bacteria to find something tasty?
 
Biology news on Phys.org
rot is usually a fungal thing.

The reason dry sugar doesn't decay is because it has so little water no organism can grow on it.

Syrups will show a fungal mat on the exposed surface after a while. But, again, water limits most organisms from growing on syrup due to extreme ex-osmotic (water movement out of the cells) pressures. Fungi don't seem to mind this as much as do other microbes.

If you want activity: make about a 20% sugar solution, let it sit exposed for a few days.
 
pikapika! said:
So what does it take for bacteria to find something tasty?
Bacteria find sugar very tasty, you grow them on Agar - a type of sugar.
As Jim said, the problem is that sugar absorbs water very strongly. If a bacteria lands on sugar this effect is so strong that the water from inside the bacteria is pulled out into the sugar and the bacteria die.
 
Agar is a sulfated polymer of galactose. It is essentially devoid of free simple sugars. Microbes are usually grown on a medium that has bacteria-style nutrition mixed into an agar solution. Agar solutions are liquid above ~45C and don't mind being autoclaved. Which is why agar is used.

Agar acts as a support medium, like a gelatin.
 
Thanks - I was just trying to simplify the 'osmotic pressure' explanation.
 
More simply, sugar, like salt, is a dessicant.
 
Pardon me for jumping in but there's something I've been wondering about. What if a microbial pathogen were engineered to mimic the properties of the standard growing medium. Would it be able to hide in plain sight, so to speak?
 

Similar threads

Can Bacteria Safely Produce Venom for Anti-Venom Research?
  • · Replies 2 ·
Replies
2
Views
2K
Why is it difficult to stain dormant bacteria with Nucleic acid dyes?
  • · Replies 6 ·
Replies
6
Views
2K
Could Gut Bacteria Exist in the Brain Tissue of Mammals?
  • · Replies 2 ·
Replies
2
Views
2K
Medical The role of bacteria in cancer development
  • · Replies 7 ·
Replies
7
Views
3K
How is bacteria added to a septic tank?
  • · Replies 13 ·
Replies
13
Views
2K
Why do bacteria insert their genes into a host?
  • · Replies 2 ·
Replies
2
Views
2K
Why doesn't sugar grow mold in dry form?
  • · Replies 14 ·
Replies
14
Views
31K
Medical Bacteriophage treats antibiotic-resistant bacterial infection
  • · Replies 18 ·
Replies
18
Views
6K
Medical The Cause of Alzheimer's: Mouth Bacteria ?
  • · Replies 2 ·
Replies
2
Views
3K
Why is too much sugar bad for us?
  • · Replies 20 ·
Replies
20
Views
12K