288 Microbes and You 



This is a food infection rather than a food poisoning. The in- 

 cubation period with Salmonella usually lasts longer than twelve 

 hours with a sudden onset of chills, headache, abdominal cramps, 

 vomiting, diarrhea, fever, and eventual prostration. 



Food may be infected by human carriers and by rodents and 

 insects which may serve as either passive or active carriers. Im- 

 properly cooked meat from animals infected with Salmonella may 

 also cause this type of food infection. The microbes are gram 

 negative rods, non-sporulating, and they usually exhibit active 

 motility in young broth cultures. Since these organisms are 

 excreted in the feces of man, the importance of excluding carriers as 

 food handlers should not be minimized. If a carrier happens to be 

 a housewife who prepares food for her own family, sound sanitary 

 practices with respect to adequate hand washing are imperative. 



Salmonella typhimurium, the cause of mouse typhoid, has been 

 the cause of some serious food infections, especially in military 

 camps. Insects and vermin must be excluded from areas where 

 food is being prepared and being served if infection of individuals 

 is to be avoided. 



Since salmonellae are non spore-forming, they are not par- 

 ticularly resistant to heating; boiling temperature will kill them in a 

 few minutes. The importance of proper refrigeration should be 

 mentioned again as an important link in helping to minimize the 

 chain of infection. 



BOTULISM 



The name botulism is derived from the Latin and means 

 sausage. It had its origin many years ago in Europe where 

 sausages were found to be the cause of serious food-borne poison- 

 ings, and the etiological agent is Clostridium bottdinum, an anaero- 

 bic spore-forming rod. Because of the marked resistance of these 

 spores to heat, the canning industry sets the time and temperature 

 of processing foods with the destruction of these spores as the 

 basis. 



During growth of Clostridium botulinum it excretes a true 

 exotoxin, which is one of the most powerful biological poisons 

 known to man. The toxin has a marked affinitv for nerve tissue 



