Laboratory Outline for General Bacteriology 



BACTERIA IN MEATS 



Meats are brought directly from the market to the laboratory. 

 Those not already ground are passed through sterilized meat 

 grinders. Weigh out 5 grams on sterile paper. Place in warm 

 mortar. Add enough sterilized quartz sand to grind well. After 

 grinding well add little by little 95 cc. of warm (about 38 C.) 

 sterilized water. This makes a dilution of 20. Use bottles for the 

 further dilutions required. For Hamburg steak and sausage use 

 dilutions of 200,000 and 100,000; for mutton, veal, and pork 

 use 100,000 and 50,000. Make four agar plates from each sample. 

 Incubate at 37 C. for two days. Count plates and find the number 

 of bacteria per gram of meat. 



TESTING FOR PRESENCE OF SPORES 



Inoculate tubes of sterile nutrient broth with the following : 



1. Potato parings 



2. Hay 



3. Corn meal 



4. Hamburg steak 



5. Oatmeal 



6. Wheat meal 



7. Beans 



8. Old milk 



9. Mornings milk 



10. Sweet corn 



11. Raisins 



After inoculating place in steam sterilizer in flowing steam 

 for 15 minutes. This kills all vegetative forms. Incubate. After 

 seven days examine tubes and make records of presence or ab- 

 sence of growth. 



CONVERSION FACTORS 



Grams to grains multiply by 15.432 



Grams to ounces avoirdupois 

 Kilograms to pounds 



Cubic centimeters to fluid ounces imperial 

 Liters into fluid ounces imperial 

 Meters into inches 



55 



0.03527 



2.2046 



0.0352 



35.2 



39.37 



