Experiments on the Spoilage of Tomato Ketchup

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Arvill Wayne Bitting. Experiments on the Spoilage of Tomato Ketchup

LETTER OF TRANSMITTAL

INTRODUCTION

PROCESS OF MANUFACTURE

SELECTION AND PREPARATION OF STOCK

PULPING

COOKING AND SEASONING

EVAPORATION AND FINISHING

BOTTLING

PROCESSING

CHARACTER OF PRODUCTS

FIRST-CLASS PRODUCTS

INFERIOR PRODUCTS FROM “TRIMMING STOCK.”

LABELS

MANUFACTURING EXPERIMENTS WITHOUT THE USE OF PRESERVATIVES

OUTLINE OF THE EXPERIMENTS

DISCUSSION OF RESULTS

SPOILAGE OF KETCHUP AFTER OPENING

SPOILAGE OF UNOPENED KETCHUP

SPOILAGE OF MARKET BRANDS

STERILITY OF KETCHUP

EXPERIMENTS WITH PRESERVATIVES

SODIUM BENZOATE

SALT

SUGAR

SPICES

WATER INFUSIONS

ACETIC-ACID EXTRACTS

OIL EXTRACTS

VINEGAR AND ACETIC ACID

OIL

STUDY OF PENICILLIUM IN KETCHUP

DEVELOPMENT

REPRODUCTION

GROWTH IN KETCHUP

TEMPERATURE TESTS

HISTOLOGICAL STRUCTURE OF KETCHUP

MICROSCOPIC EXAMINATION OF SOME COMMERCIAL BRANDS

SUMMARY

Отрывок из книги

The tomato, Lycopersicum esculentum, is supposed to be native to South or Central America. The large fruits commonly used grow only under cultivation, but the variety with small, spherical fruits, known as L. cerasiforme, has been found on the shore of Peru and is considered by De Candolle1 as belonging to the same species as L. esculentum. Though grown extensively in Europe, there is nothing to indicate that it was known there before the discovery of America. The tomato was introduced into China and Japan at a comparatively recent date. De Candolle is of the opinion that the tomato was taken to Europe by the Spaniards from Peru and was later introduced into the United States by Europeans. Tomatoes were brought to Salem, Mass., by an Italian painter in 1802,2 who is said to have had difficulty in convincing the people that they were edible. They were used in New Orleans in 1812, though as late as 1835 they were sold by the dozen in Boston. After 1840 they came into general use in the Eastern States, but it was later than this before tomatoes were used freely in the Western States, many persons having the impression that, since they belonged to the nightshade family, they must be unwholesome. The extent to which tomatoes are used at the present time shows how completely this prejudice has been overcome.

The name Lycopersicum is from two Greek words, meaning a wolf, and a peach, the application of these terms not being apparent; the name of the species, esculentum, is from the Latin, meaning eatable. The common name “tomato” is of South or Central American origin, and is believed to be the term used in an ancient American dialect to designate the plant,3 but its meaning is unknown. The English call the tomato “love apple,” which in French is “pomme d’amour.”

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The tomatoes should be home-grown, of a red variety having the minimum of yellow and purple color, be picked when ripe, and delivered to the factory promptly without mashing. All tomatoes should pass over an inspection table, the rotten and otherwise unfit fruit should be discarded, and the green tomatoes should be returned to crates to ripen. The stems should be removed when the best color is desired, and the tomatoes should be thoroughly washed to remove dirt and mold. Dumping a crate of tomatoes into a hopper of dirty water and playing a gentle spray of water on part of them merely wets the skin and makes them appear bright.

The clean tomatoes should be conveyed to the steaming tanks and subjected to steam heat until the skins burst and the meat softens. After a short heating the tomatoes should be run through a “cyclone” where the skins, seeds, etc., are removed and they are rubbed to a pulp. To remove very small particles and fiber, the pulp may be run through a sieving machine at once; or, if ketchup of the smoothest possible kind is to be made, this procedure should be delayed until after the cooking. The pulp is collected in a receiving vat, and only such an amount should be provided in advance as will keep the kettles full, as it is better to stop the tomatoes before going to the washer than to have the pulp stand for some hours. In common practice, however, the pulp is either sent to the cooker at once, or it is allowed to stand and partially separate. If tall casks are used for this separation the solids will rise to the top and the clear watery portion is drawn off at the bottom, or the pulp may be strained through cloth bags. The object of this separation is to secure greater concentration of the solids, retain a brighter color, and shorten the time of cooking.

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