[5] The U.S. Food and Drug Administration defines cream cheese as containing at least 33% milk fat with a moisture content of not more than 55%, and a pH range of 4.4 to 4.9.[6] Similarly, under Canadian Food and Drug Regulations, cream cheese must contain at least 30% milk fat and a maximum of 55% moisture.In 1903, Reynolds sold rights to the "Philadelphia" brand name to the Phenix Cheese Company, which was under the direction of Jason F. Whitney, Sr. (which later merged with Kraft, in 1928).Amino acids at the surface of the proteins begin losing charge and become neutral, turning the fat micelles from hydrophilic to hydrophobic state and causing the liquid to coagulate.If the bacteria are left in the milk too long, the pH lowers further, the micelles attain a positive charge, and the mixture returns to liquid form.[citation needed] Inaccurate timing of the heating can produce inferior or unsalable cheese due to variations in flavor and texture.