Issued January 9, 1909. U. S. DEPARTMENT OF AGRICULTURE, BUREAU OF CHEMISTRY--BULLETIN No. 119. H. W. WILEY, Chief of Bureau. EXPERIMENTS ON THE SPOILAGE OF TOMATO KETCHUP. BY A. W. BITTING, INSPECTOR, BUREAU OF CHEMISTRY. [Illustration: Shield of the United States Department of Agriculture] WASHINGTON: GOVERNMENT PRINTING OFFICE. 1909. LETTER OF TRANSMITTAL. U. S. Department of Agriculture, Bureau of Chemistry, _Washington, D. C., July 15, 1908_. Sir: I have the honor to submit for your approval a report made by Inspector Bitting of experimental work on the spoilage of tomato ketchup, the conditions contributing thereto, methods of prevention, the action of preservatives, and the length of time that the product will keep under varying conditions of manufacture and temperature, both before and after opening. Every effort has been made to conduct the work in a practical way, and the results obtained can not fail to be of interest and profit both to the manufacturer and consumer. I recommend that this report be published as Bulletin No. 119 of the Bureau of Chemistry. Respectfully, H. W. Wiley, _Chief_. Hon. James Wilson, _Secretary of Agriculture_. CONTENTS. Page. Introduction 7 Process of manufacture 8 Selection and preparation of stock 9 Pulping 9 Cooking and seasoning 10 Evaporation and finishing 11 Bottling 11 Processing 11 Character of products 12 First-class products 12 Inferior products from “trimming stock” 13 Labels 14 Manufacturing experiments without the use of preservatives 15 Outline of experiments 15 Discussion of results 17 Spoilage of ketchup after opening 17 Spoilage of unopened ketchup 20 Spoilage of market brands 20 Sterility of ketchup 21