CONTENTS ix 



PACT 



VII. The Addition of Preservatives 119 



1. Carbonate or Bicarbonate of !Soda 119 



'2. Boracic Acid and Borax 120 



3. Salicylic Acid 120 



4. Benzoic Acid 121 



5. Formaldehyde 121 



6. Hydrogen Peroxide 122 



(a) Qualitative Estimation 122 



(b) Quantitative Estimation 123 



The Fermentation Test with Milk 124 



The Reductase Test 127 



PART II. -BUTTER. 



PAliE 



INTRODUCTORY 130 



EXAMINATION OF BUTTER 134 



A. Sampling 134 



B. The Chemical Analysis 135 



I. Determination of the Water 135 



II. Determination of the Fat 137 



(a) Scientific Methods 137 



1. The Extraction Method 137 



2. Rose-Gottlieb Method 138 



3. Indirect Determination of Fat, 139 



(b) Practical Methods 139 



Bernstein's Method 139 



III. Determination of the Anhydrous Solids, -not Fat .... 140 



IV. Determination of Protein 141 



V. Estimation of Common Salt 141 



VI. Proof of Pasteurisation 141 



EXAMINATION OF THE BUTTER FAT 142 



A. Physical Tests 142 



I. Determination of the Specific Gravity of Butter Fat (at 



100 C) " 142 



II. Determination of the Melting Point and the Point of 



Solidification 142 



(a) The Melting Point 142 



(b) The Point of Solidification " . . 143 



III. Determination of the Critical Temperature of Solution 



in Alcohol . 144 



