2 replies to this topic

[AdamR]

Hi,

 

I know that it's the exotoxin of Food Poisoning bacteria that cause illnes (staph aurues, bacillus cereus, clostridium, etc) but wondered if ingesting just the bactera could also make you ill? (I know it does with food borne illness - campylobactyer, e-coli, etc)

 

For example, if staph aurues has multiplied to high levels but had not yet produced any exotoxin onto the food, could ingesting just the staph cells make you ill?

[George @ Safefood 360°]

My understanding is that the bacteria itself is relatively harmless to healthy humans. I think about 50% of the population are carriers and asymptomatically. During food preparation when the conditions are right for enterotoxin production that the risk occurs following ingestion. The toxin as you know is very heat resistant and may not be destroyed by cooking although the pathogen will. In terms of food safety I think this is the important information for risk assessment and control.

 

Regarding whether the pathogen can grow in the human intestine and continue to produce toxin - i cant say for sure but it is not mentioned in the usual reference sources. It is a poor competitor with other m/o's and the conditions may not be suitable. I think the hosts immune system would also play a factor. 

 

Staphyloccus Aureus does cause skin and soft tissue infections in hospitals and the general community and the most severe impacts are usually caused by the action of toxins. This however is beyond the scope of food safety although hand washing is a major factor in both food production and rates of infection in hospitals. I think in terms of food safety risk assessment you can address it from the point of toxin formation during preparation. This is the significant factor.

 

George 

[Charles.C]

Hi,

 

I know that it's the exotoxin of Food Poisoning bacteria that cause illnes (staph aurues, bacillus cereus, clostridium, etc) but wondered if ingesting just the bactera could also make you ill? (I know it does with food borne illness - campylobactyer, e-coli, etc)

 

For example, if staph aurues has multiplied to high levels but had not yet produced any exotoxin onto the food, could ingesting just the staph cells make you ill?

 

Dear AdamR

 

Interestingly simple question, not so simple to answer.

George has presented a general evaluation of the harmful significance of S.aureus.

 

S.aureus (some strains) is considered to be associated with the occurrence of  foodborne intoxication.

As per the attachments below, this implies that the answer to yr last paragraph is “No” although at levels of  >=10^5, the probability of Staph.Enterotoxin occurring is presumably high anyway ?. I guess the typical “M” limits used for cooked foods have a substantial safety factor.

 

 hh1 - major types of foodborne illnesses -- infection, intoxication, and toxin-mediated infection.pdf   50.01KB   13 downloads

 hh2 edis, causative agents of foodborne illness.pdf   203.26KB   9 downloads

 

The spectrum of staphylococcal infections ranges from pimples and furuncles to toxic shock syndrome and sepsis, most of which depend on numerous virulence factors. On the other hand, some infections, such as staphylococcal food poisoning, rely on one single type of virulence factor: the SEs

 

 hh3 - Staphylococcus aureus and food poisoning.pdf   822.49KB   12 downloads

 

If you are interested in a quite detailed, fairly recent, and pictorially impressive analysis of S.aureus’s capabilities  -

 hh4 - S.aureus, 4th European Symp.Food Safety.pdf   3.04MB   12 downloads

 

Rgds / Charles.C