28 EXPERIMENTS ON THE SPOILAGE OF TOMATO KETCHUP. 



marked effect in preventing spoilage. That the oils affected the 

 development of the mold was evident. The mold developed first 

 at the junction of the ketchup with the bottle forming a ring which 

 spread gradually over the surface developing a somewhat heavy 

 mycelium. This remained white longer than usual, spores forming 

 very gradually, as indicated by the change in color from white to a 

 delicate blue. At the end of three weeks only spots of color appeared 

 on the surface and these were still blue, though in ordinary develop- 

 ment the blue color changes to green in two or three days. 



Another test was made, using olive oil only, and in the proportions 

 of 1 part of oil to 500, 400, and 300 parts, respectively, of the ketchup. 

 Keduction was made in a steam-jacketed kettle, the oil being added 

 when the ebullition of the ketchup was the strongest, after which 

 the boiling was continued for fifteen minutes. The ketchup was 

 bottled, unsterilized bottles being used, then covered loosely with 

 the metal caps. 



The time required for the ketchup to spoil was longer than in the 

 first set, but there was not sufficient difference nor enough uniformity 

 in the time to indicate that the use of oil in ketchup is desirable, ev4J| 

 if the change of flavor and odor be not taken into consideration. Thfe 

 average number of days before spoilage for those containing 1 part (II 

 oil to 500 parts of ketchup, was thirteen and two-thirds days ; one has 

 has not yet spoiled (a period of forty-five days), while the first bottle 

 spoiled in four days. Those having 1 part of oil to 400 parts of ketchup 

 had an average life of nine and three-fourths days, the minimum being 

 three days, and the maximum twenty-six days. Those having 1 part 

 to 300 parts of ketchup on an average did not spoil for six and three- 

 fourths days, the minimum being four days, and the maximum 

 eleven days. 



The failure of some of the bottles to spoil, though similar in every 

 known respect to those which did spoil, is a feature peculiar to ketchup 

 and is familiar to manufacturers who make careful tests before putting 

 their product on the market. For this reason a rather large number 

 of bottles should be used in a test in order that the results may be 

 approximately accurate and represent general conditions. 



STUDY OF PENICILLIUM IN KETCHUP. 



Penicillium is a plant which is distributed widely and apparently 

 is able to grow wherever organic matter is found, though flourishing 

 best when the material contains acid. It causes loss in canneries, 

 breweries, distilleries, etc., the only use made of it being in the manu- 

 facture of Roquefort cheese, the immature cheese being inoculated 

 with the conidia for the effect the mold produces in the maturing 

 process. 



