20 KXPKKIA1ENTS ON THE SPOILAGE OF TOMATO KETCHUP. 

 SPOILAGE OF UNOPENED KETCHUP. 



Another test was made to determine whether the ketchup would 

 spoil when kept in a warm place, but not opened. Three bottles 

 from each experimental batch were placed in the incubator Novem- 

 ber 7, 1907, and were kept there until December 23, 1907 forty-six 

 days and in that time there was no sign of spoilage. They were 

 then opened and kept in the laboratory; the average number of 

 days before spoilage occurred is indicated in the following table: 



Average number of days before spoilage of ketchup after opening (kept 46 days at 95 



before opening). 



It will be observed that these samples spoiled in about the same 

 length of time as the bottles opened in February and tested in the 

 incubator, so that similar results were obtained by keeping unopened 

 ketchup one and one-half months at 95 F. and keeping it five 

 months at 70 F. From the results of the experiments it is evident 

 that the ingredients of the ketchup in the proportions used are not 

 antiseptic, and it is also apparent from the number of organisms 

 found and the rapidity of their multiplication that ketchup is a good, 

 nutritive medium. Yeasts and molds are the predominating organ- 

 isms, and, as the ketchup is acid and also contains sugar, and these 

 organisms are found on tomatoes in the field, their predominance in 

 the ketchup is explained". 



SPOILAGE OF MARKET BRANDS. 



To determine the keeping properties of the ketchup on the market, 

 various brands were obtained from the grocery stores. In the 

 majority of cases nothing was known of the ingredients or methods 

 of manufacture, except what appeared on the labels. No date of 

 manufacture was given, and in some cases the dealers did not know 

 the age of the product. 



There were 104 bottles of ketchup opened to find out how long they 

 would remain in good condition. These were kept in the laboratory, 

 though the temperature was higher than that at which ketchup 

 should be held. Of the 104 bottles there were 66 without preservative, 

 according to the labels, 46 of which spoiled. Of the 20 which did not 

 spoil, 2 formed crystals of benzoic acid on the covers of glass dishes 



