460 BACTERIOLOGICAL ANALYSES 



EXAMINATION OF UNSOUND MEATS. 



(INCLUDING TINNED OR POTTED MEATS, FISH, ETC.) 



The bacterioscopic examination of unsound food is 

 chiefly directed to the detection of those members of 

 the Coli-typhoid group B. enteriditis of Gaertnerand 

 its allies which are usually associated with epidemic 

 outbreaks of food poisoning, and such anaerobic bac- 

 teria as initiate putrefactive changes in the food which 

 result in the formation of poisonous ptomaines, conse- 

 quently the quantitative examination pure and simple 

 is frequently omitted. 



A. Cultural Examination. 

 Quantitative. 



Apparatus Required: 



Sterilised tin opener, if (necessary.) 



Erlenmeyer flask (500 c.c. capacity) containing 200 c.c. sterile 

 bouillon and fitted with solid rubber stopper. 



Counterpoise. 



Scissors and forceps. 



Scales and weights. 



Water steriliser. 



Hypodermic syringe. 



Syringe with intragastric tube. 



Rat forceps. 



Case of sterile capsules. 



Filtering apparatus as for water analysis. 



Case of sterile plates. 



Case of sterile graduated pipettes, 10 c.c. (in tenths of a cubic 

 centimetre) . 



Case of sterile graduated pipettes, i c.c. (in tenths of a cubic 

 centimetre) . 



Plate-levelling stand. 



Tubes of nutrient gelatine. 



Tubes of nutrient agar. 



Water-bath regulated at 42 C. 



Bulloch's apparatus. 



METHOD. 



i. Place the flask containing 200 c.c. sterile broth 

 on one pan of the scales and counterpoise accurately. 



