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Author Topic: What is the microbiological basis of food poisoning?  (Read 6249 times)

Offline The Scientist

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Is food poisoning caused by insects or the unclean food itself? Or are there chemicals which causes the poisoning,where the next day you'll get a fever and diarrhoea. Please share your views with us, thanks!
« Last Edit: 25/12/2010 00:08:36 by chris »


 

SteveFish

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Re: What is the microbiological basis of food poisoning?
« Reply #1 on: 22/12/2010 17:54:32 »
Food poisoning is caused by eating food that contains certain viruses and microorganisms. One of the most common causes of food poisoning are some of the bacteria in the genus Salmonella. Because most food poisoning involves something bad living in the intestines, the infective agent is excreted. So if infected excrement comes in contact with food, it can pass on the disease to you. The famous Typhoid Mary incident was caused by a women who was a food worker and also had an Escherichia infection. The genus Escherichia is closely related to the Salmonella genus. There are many ways for food to be infected. There are examples where the fertilizer used on a crop contained an infective agent that made it to the market. Chickens can be infected with Salmonella, but not have any symptoms, so raw eggs or not being careful in the kitchen while preparing a chicken for cooking can make you sick. Cooking to the recommended temperature will make infection very rare. Steve
 

Offline Variola

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Re: What is the microbiological basis of food poisoning?
« Reply #2 on: 22/12/2010 18:12:16 »
Quote
The famous Typhoid Mary incident was caused by a women who was a food worker and also had an Escherichia infection. The genus Escherichia is closely related to the Salmonella genus. 

I am nitpicking here, but Mary Mallon had S.Enterica which causes typhoid fever not E.Coli  :)

It is worth pointing out that our stomach pH, and Peyer's patches (found in the GI tract) protect us from most of the pathogens that enter our digestive system. But many can still infect us as they have built up defences that avoid out own. They often rely on excretion via faeces as a mode of infection. However as Steve points out, good hygiene and cooking food well eliminates most of the risk.
 

SteveFish

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Re: What is the microbiological basis of food poisoning?
« Reply #3 on: 22/12/2010 18:25:31 »
Variola, I love being nipicked when it is accurate, and I, therefore, stand corrected. Typhoid is a Salmonella species, not of the genus Escherichia. Salmonella and Escherichia are closely related genera. Thanks, Steve
 

Offline Variola

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Re: What is the microbiological basis of food poisoning?
« Reply #4 on: 22/12/2010 18:33:19 »
Quote
Variola, I love being nipicked when it is accurate

Yes but it reminds me I really do need to get a life....  :)
Typhoid Mary was a really interesting story, and even more fascinating that she remained highly infectious but without developing the disease.

Oh and feel free to call me Pox, everyone else does  :)Variola is so formal.... lol
 

Offline chris

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Re: What is the microbiological basis of food poisoning?
« Reply #5 on: 22/12/2010 19:01:42 »
One important point to add to the list of causes of food poisoning, apart from organisms like viable bacteria and viruses, is toxins.

Certain bacteria, whilst not necessarily capable of growth within the human GI tract, can colonise and reproduce within foodstuffs, secreting as they do so heat-stable enterotoxins.

So even if the food is reheated sufficiently well to destroy the bugs, the toxin survives and is then consumed, with gastronomic consequences.

These usually manifest within a few hours of consuming the food. The symptoms are usually intense and relatively shortlived, resolving completely within 24 hours.

A classic example of this is Staph aureus; food handlers carrying Staph (which is a common skin commensal) can transfer the bugs to food items. If these are improperly stored (i.e. at warm temperatures) the bugs can flourish, especially on protein-rich items like meats, secreting heat-resistant toxins into the food.

These toxins damage enterocytes (intestinal lining cells), causing the bowel mucosa to become "leaky" and irritated. Fluid accumulates within the bowel lumen, triggering diarrhoea, and the irritation provokes vomiting. Nice.

Chris
 

SteveFish

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Re: What is the microbiological basis of food poisoning?
« Reply #6 on: 22/12/2010 19:16:20 »
Chris ... such as Botulinus toxin, nasty stuff. Good addition. Steve
 

Offline Variola

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Re: What is the microbiological basis of food poisoning?
« Reply #7 on: 22/12/2010 20:59:26 »
Yup indeed, in fact *most of the severe cases of food poisoning are caused by bacteria producing enterotoxins, simply because the toxins are so effective at causing the influx of chlorides/water into the lumen,usually by increasing levels of cyclic-AMP activity as I recall. I think some viruses work in a similar fashion by producing enterotoxins.. (Chris?).

Botulinum is an incredibly effective toxin,hardly any of it is needed,  it completely disrupts vesicle transport of neurotransmitters by attacking the proteins (SNARES) that enable them to dock and fuse.
Personally, I would rather be wrinkly...!! 


*denotes not a scientific term and is reflective of my opinion, but without referring to my notes... which are upstairs...  :)
 

Offline CliffordK

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Re: What is the microbiological basis of food poisoning?
« Reply #8 on: 23/12/2010 01:51:00 »
For organic "Food Poisoning", it is essentially an adaptation of the microorganisms to pass through the GI tract of hosts, and spread to other hosts...   in what is termed as "Fecal-Oral" disease transmission.

These would be in contrast to airborne transmission types such as the common cold, or pneumonia causing organisms.

You can also have inorganic types of food poisoning, or food borne toxins, such as mercury, arsenic, and other heavy metal poisoning. 
 

SteveFish

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Re: What is the microbiological basis of food poisoning?
« Reply #9 on: 23/12/2010 02:46:02 »
Variola, just to increase the scary, SNARES are important for vesicle trafficking in every cell in the body. Steve
 

Offline The Scientist

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Re: What is the microbiological basis of food poisoning?
« Reply #10 on: 23/12/2010 08:16:49 »
Thanks all! But I was wondering, what are the chances of it happening? Assuming the food is cooked at the recommended temperature and that the consumer is healthy. By the way, are children more vulnerable in getting food poisoning?
 

Offline CliffordK

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Re: What is the microbiological basis of food poisoning?
« Reply #11 on: 23/12/2010 10:37:23 »
Keep in mind that most "food poisoning" is relatively mild.

As mentioned there are a number of different types of food poisoning.  With Staph Aureus food poisoning the bacteria is often already dead, and just leaves the toxins (which require higher temperatures to destroy).

Anyway, I suppose people could live most of their lives without getting some tainted food or water...  But one shouldn't be over concerned with it either. 

The "rules" when you travel might not be the same either.  Some people bring some anti-diarrhea meds just in case, especially if traveling to 3rd world nations. 

Personally I think some of the food management regulations are a bit over the top here in the USA.  Too much perfectly good food is thrown out.
 

Offline The Scientist

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Re: What is the microbiological basis of food poisoning?
« Reply #12 on: 23/12/2010 10:54:25 »
Hmm, can the bacteria contaminate water then? So we do not only eat just to have food poisoning, we drink too?
 

Offline Variola

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Re: What is the microbiological basis of food poisoning?
« Reply #13 on: 23/12/2010 11:41:19 »
Variola, just to increase the scary, SNARES are important for vesicle trafficking in every cell in the body. Steve

Yup, the SNARE family is huge, with many smaller sub-families, all of which are dedicated to vesicle targeting and fusion.
Somehow, a few wrinkles does not seem worth the risk!
 

Offline Variola

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Re: What is the microbiological basis of food poisoning?
« Reply #14 on: 23/12/2010 11:42:25 »
Hmm, can the bacteria contaminate water then? So we do not only eat just to have food poisoning, we drink too?

Yes, hence all the anti-bacterial additives in our tap water.
 

Offline The Scientist

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Re: What is the microbiological basis of food poisoning?
« Reply #15 on: 23/12/2010 12:13:42 »
Hmm, can the bacteria contaminate water then? So we do not only eat just to have food poisoning, we drink too?

Yes, hence all the anti-bacterial additives in our tap water.


So are most food poisoning cases caused by drinking contaminated water?
 

Offline CliffordK

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Re: What is the microbiological basis of food poisoning?
« Reply #16 on: 23/12/2010 12:26:49 »
Not only can it be in the water...
But rumors have it can also be in the ice cubes you put in your carefully selected sterile drinks. [xx(]

Giardia is a water-borne parasite that can affect campers, which is a reason many campers now use filters, bleach/chlorine, or boiling their water.

-----------------

I assume different organisms will have different delivery mechanisms.

Giardia is usually water-borne.
Enterotoxigenic E-Coli (Traveler's Diarrhea) is likely either food or water borne.
Enterohemolitic E-Coli (the deadly stuff) is likely transferred onto the surface of food (or ground up into hamburger).
Staph Aureus (the less than 24 hr food sickness, diarrhea) is likely food borne, bacteria multiplies and produces toxins before consumption.
Salmonella...  Not sure, probably either food or water.
Botulism...  Food Borne, usually poorly canned foods.
Cholera...  either food or water borne
Hepatitis A...  Fecal-Oral, either food or water.
« Last Edit: 23/12/2010 12:28:43 by CliffordK »
 

Offline The Scientist

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Re: What is the microbiological basis of food poisoning?
« Reply #17 on: 23/12/2010 12:44:09 »
I was thinking, do pesticides and insectisides used on plants contribute to the factors of having food poisoning?
 

Offline Variola

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Re: What is the microbiological basis of food poisoning?
« Reply #18 on: 23/12/2010 13:15:56 »
I was thinking, do pesticides and insectisides used on plants contribute to the factors of having food poisoning?

Not unless you are a caterpillar or beetle... :)
 

Offline Bored chemist

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Re: What is the microbiological basis of food poisoning?
« Reply #19 on: 23/12/2010 14:52:17 »
I was thinking, do pesticides and insectisides used on plants contribute to the factors of having food poisoning?
Strange as it may seem, the people who make pesticides choose materials that are very toxic to pests and not very toxic to people.
 

Offline The Scientist

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Re: What is the microbiological basis of food poisoning?
« Reply #20 on: 23/12/2010 15:00:34 »
I was thinking, do pesticides and insecticides used on plants contribute to the factors of having food poisoning?
Strange as it may seem, the people who make pesticides choose materials that are very toxic to pests and not very toxic to people.

But I believe that the chemicals they use are still toxic no matter what the intensity is. So do you believe that pesticides and insecticides do contribute to food poisoning? What do you think? Or are the toxic negligible to be counted? Thanks!
 

Offline Variola

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Re: What is the microbiological basis of food poisoning?
« Reply #21 on: 23/12/2010 16:18:52 »
Food poisoning is caused my microbes.
Insecticides are designed to kill insects, not microbes.
While I do think that some of the older pesticides around can have some side effects on humans, it is not related to food poisoning whatsoever.
The reasons insecticides do not affect us is because we do not have the right receptors in out intestinal lumen for the toxin to work on.
Hence if I felt the urge, I could go into the lab, lick a plate of B. Thuringiensis that growing in the incubator and come to no harm whatsoever  :)4
Not that I would, they smell like old feet!  [xx(]
 

Offline The Scientist

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What is the microbiological basis of food poisoning?
« Reply #22 on: 29/12/2010 07:19:56 »
Are there any vaccinations to prevent from getting food poisoning?
 

Offline CliffordK

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What is the microbiological basis of food poisoning?
« Reply #23 on: 29/12/2010 10:51:19 »
From the list above, I believe that Hepatitis A is the only Fecal-Oral disease that is commonly vaccinated against.  Polio is also a Fecal-Oral transmitted disease that has a vaccine.

As mentioned, most of the other diseases are relatively mild, or can be treated with supportive care with minimal mortality, or other long-term effects. 

Some such as Staph Aureus and Botulism are based on toxin build-up, and it is quite possible that previous exposure, or a vaccine would not improve the outcome.
 

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What is the microbiological basis of food poisoning?
« Reply #23 on: 29/12/2010 10:51:19 »

 

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