Food Engineering/Manufacturing/Ph change with time


Peter, when you say the pH can change with time as the composition equilibrates. Does that mean that my reading of ph of 3.7 can rise to 4.6 overtime? Cornell said that my shelf stable product overtime would be a quality issue but will never really "spoil". before i bottle the sauce and the ph reads 3.7. what processes are used for me to be sure that the PH won't rise overtime? if the PH changes is it likely to go lower or higher? and between what ranges will it change by? Thanks Peter. You are the best. I've read that you are a process authority also. Where can i reach you to do business in the future? What is your rate? i am located in New york.


Typically, pH may change by 0.5 units, usually going up. A high oil product may become rancid over time due to oxidation. You probably cannot prevent some change in pH, but it usually is small.

You can reach me by private email at  phone 708-848-2205, suburb of Chicago. My professional fees are $200/hr plus expenses at cost.  

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J. Peter Clark


How various processed foods are made; ways to improve manufacturing; how to make a new food product.


Employment history: Research Engineer, U.S.Agricultural Research Service, Associate Professor Chemical Engineering, Virginia Tech, Director of Research, Continental Baking Company, President, Epstein Process Engineering, Inc., Vice Presdent Technology, Fluor Daniel, Inc., Consultant to the Process Industries

Organizations: American Institute of Chemical Engineers (Fellow) Institute of Food Technologists, American Association of Cereal Chemists, American Association of Candy Technologists, American Society of Agricultural Engineers,

Publications: Several Encyclopedias (Kirk and Othmer, Chemical Technology; Food Science, Food Technology and Nutrition; Wiley Encyclopedia of Food Science and Technology; Encyclopedia of Life Support Systems); five books, two book chapters; numerous journals.

Education: BSChE Notre Dame PhD University of California, Berkeley

Awards: AIChE Food, Pharmaceutical and Bioengineering Division Award 1998

Clients: Major food processing and pharamaceutical companies.

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