EXTENT OF ADULTERATION. From 25 to 41 per cent of the invoices of Sicilian sumac imported into the country are adulterated, and this adulteration is effected almost exclusively with lentiscus. These adulterated shipments are, as a rule, so labeled as to convey the impression that they are pure Sicilian sumac. It is sometimes claimed that shipments of sumac are mixed with lentiscus in accordance with the order of the importer. In such cases the consignment should be properly labeled indicating the amount of lentiscus used. The tannin content is from 2 to 7 per cent lower in the adulterated samples than in the pure sumacs, averaging about 4.5 per cent lower, and the color of the extract prepared from them is much darker than that of pure sumac extracts. While to the experienced analyst the color of the extract or of the dried material is generally indicative of the purity of the sample, only microscopical examination can definitely determine this question. The adulteration of Sicilian sumac is of more importance than is indicated merely by a lower tannin content, otherwise American. sumac could be used at a much smaller cost. When high-grade, light-colored leathers or durable sumac-tanned leathers are required, as for instance in bookbinding, adulteration results in discoloration and destruction of the leather in a much shorter time than when pure sumac is employed in tanning, and the money loss thus occasioned is many times the difference in cost between a pure and an adulterated sumac. Aside from any ethical consideration, there is absolutely no advantage to the tanner in the purchase of adulterated sumac because, as a matter of fact, the tannin in such sumac costs more for given amount than when bought in pure sumac. Thus taking the current quotations of from $71 to $72 per ton for sumac containing 29 per cent of tannin, $70 to $71 for 28 per cent, and $69 to $70 for 27 per cent, the tannin costs from 12.2 to 12.4 cents, from 12.5 to 12.7 cents, and from 12.7 to 13 cents per pound, respectively. That is, the tanner is making a lower grade leather at a greater cost when using adulterated sumac. Finally, as there may be a variation of as much as 10 per cent in the tannin content of pure sumac, it should always be bought on the basis of its tannin content, and if adulterated should be so labeled. 158 CU.S. Issued September 18, 1908. U. S. DEPARTMENT OF AGRICULTURE, BUREAU OF CHEMISTRY-BULLETIN No. 118. H. W. WILEY, Chief of Bureau. GENERAL LIBRARY, UNIV. OF MICH. 1908 Division of Foods: H. W. WILEY, Chemist and Chief of Bureau. F. B. LINTON, Chief Clerk. W. D. BIGELOW, Chief. WASHINGTON FOOD INSPECTION LABORATORY L. M. TOLMAN, Chief. Chief Food and Drug Inspector: Food and Drug Inspection Laboratories: Buffalo, W. L. DUBOIS, Acting Chief. Chicago, A. L. WINTON, Chief. Cincinnati, B. R. HART, Acting Chief. Denver, A. E. LEACH, Chief. Detroit, H. L. SCHULTZ, Acting Chief. Galveston. (Not appointed.) Honolulu, Hawaiian Islands, R. A. DUNCAN, Acting Chief. Kansas City (Mo.), A. V. H. MORY, Acting Chief. Nashville. (Not appointed.) New Orleans, C. W. HARRISON, Chief. New York, R. E. DOOLITTLE, Chief. Omaha, S. H. Ross, Acting Chief. Philadelphia, C. S. BRINTON, Chie. Pittsburg, M. C. ALBRECH, Acting Chief. Portland (Oreg.), A. L. KNISELY, Acting Chief. St. Paul, A. S. MITCHELL, Chief. San Francisco, R. A. GOULD, Chief. Savannah, W. C. BURNET, Acting Chief. Sugar Laboratory: A. H. BRYAN, in charge. Miscellaneous Division: J. K. HAYWOOD, Chief. Division of Drugs: L. F. KEBLER, Chief. Contracts Laboratory: P. H. WALKER, Chief. Leather and Paper Laboratory: Microchemical Laboratory: Special Investigations: PHYSIOLOGICAL CHEMISTRY--- Animal physiology, F. C. WEBER, in charge. BACTERIOLOGICAL CHEMISTRY - G. W. STILES, Jr., in charge, Washington. M. E. PENNINGTON (food research), in charge, Philadelphia. ENOLOGICAL CHEMISTRY W. B. ALWOOD, in charge, Charlottesville, Va. NITROGEN SECTION T. C. TRESCOT, in charge. |