EXAMINATION OF MEATS 157 



d. TrichinEe in pork. 



e. Cereal fillers and starches in sausage meats. Tragacanth fillers. 

 /. Coloring substances and preservatives in sausage meats. 



2. Plate cultures. (Lactose-litmus-agar and gelatin media.) 



a. Numerical counts of bacteria. 



b. Number of gas formers and acid formers. 



c. B. hotulinus in pork meats. 



3. Tcxicological tests. 



a. Inoculation tests (guinea-pigs) to prove the absence or presence of ptomaines 

 or toxins. 



b. Tests for tuberculous and other diseased meats. 

 4. Determining the source of the meat. 



a. By the precsipitin test. 



b. Sugar test for horse meat. 



c. Microscopical identification based on differences in the size and structure of 

 the muscular fibers and the differences in the size and form of the fat crystals 

 derived from different animals. 



Of the above tests the numerical bacterial count and the toxico- 

 logical tests are of the greatest importance and should be carried 

 out in the examination of suspected raw meats, sausage meats and 

 of canned meats and soup stocks. There certainly should be a 

 limit to the number of bacteria in all raw meats, whether ground 

 into sausage or not, as this would be the means of regulating the 

 sanitary requirements in the proper handling of meats. The only 

 practical method for determining the quality of canned meats is to 

 make inoculation tests on guinea-pigs or white mice, using filtered 

 aqueous extracts of the suspected meat products. If ptomaines 

 or toxins are present the tests will show it. It would be very 

 desirable to work out a micro-chemical test for determining the 

 presence of toxins and ptomaines in meats. As above indicated, 

 there are some very important differences between toxins and 

 ptomaines. The former are destroyed by the boiling temperature, 

 whereas the latter are not. For example, the thorough cooking 

 of sausage meats prevents botulism but it does not prevent the 

 ill effects resulting from the eating of meats with ptomaine poison. 



Dried and smoked meats should be examined for the presence 

 of bacteria and molds. Dried fish 'in particular is very fre- 



