E 
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Contribution from the Bureau of Chemistry 
CARL L. ALSBERG, Chief - 
Washington, D. C. WV October 6, 1917 
MICROSCOPICAL STUDIES ON TOMATO PRODUCTS. 
By Burton J. Howarp, Microscopist in Charge, in collaboration with CHarRuEs IT. 
STEPHENSON, Scientific Assistant, Microchemical Laboratory. 
CONTENTS. 
Page. Pare. 
PE NOMC TROT a ss ttce cits cisiocte o ca ee iolasloe soe ake 1 | Relation between percentage of rot and mi- 
Relation between visual inspection ang croscopical gounts—Continued. 
microscopical examination........-..--- 2 Bacterialicounts 4 seeks vase oan oe 16 
MOMALO|PULD 4 joie sais 22 Lies setls Se eisiatee 2 | Microscopic counts on tomato sauces and 
CAUSED S AiG 6 aA sO a ae ens a ae 5 IESE Goa seecobucaeanoaloodo sosheseacarbous 16 
Products made from peeled stock. .-....- 7 | Method for microanalysis oftomato products 21 
Relation between percentage ofrot and micro- VAS PPATALUSS eA ss ee piss te ENE 21 
SCOpICA COUNTS sia 5 4a serene aciac oaece seine ce 8 Moldsittentathye) ease mrs see ee 21 
IMG GYIC OURS eee ees AA BS. 8 Yeasts and spores (tentative)._........- 22 
Laboratory samples...-..-..-...--- 8 Bactenlai (tentative). 6.4. 4022252222222 22 
IPE y Seiad S26 Sas eo dodcdeacosse 11 | Explanation of caleulations.................. 23 
Spore and yeast counts..............--.- 4s} SS tmmianye ee he eet MN A Ry, Aly oA 
INTRODUCTION. 
During the past few years the Bureau of Chemistry has conducted 
a very comprehensive investigation to establish a basis for judging 
tomato products. Experiments were conducted in the bureau 
laboratory and also in factories, a large number of which were visited. 
Out of the mass of data thus collected, it is felt that the scientific 
facts underlying the relationship between microorganisms and the 
rot and decay of tomato products should be of value to manufacturers 
and food control officials at this time. The results bearing upon the 
relation of the physical condition of the stock from which tomato 
products are made to the number of microorganisms present in 
tomato products are therefore given in this bulletin. 
A great many tests at factories were made by noting the general 
condition of the stock and then examining microscopically samples 
of the finished product. The criteria published in 1911 in Bureau 
of Chemistry Circular 68,! for the guidance of manufacturers, were 
1 Sold by U. S. Superintendent of Documents Washington, D. C., for 5 cents. 
4211°—17—Bull. 581——1 
