Transactions in tobacco involving the sale thereof at auction as commonly conducted at auction markets are affected with a public interest; such transactions are carried on by tobacco producers generally and by persons engaged in the business of buying and selling tobacco in commerce; the classification of tobacco according to type, grade, and other characteristics affect the prices received therefor by producers; without uniform standards of classification and inspection the evaluation of tobacco is susceptible to speculation, manipulation, and control, and unreasonable fluctuations in prices and quality determinations occur which are detrimental to producers and persons handling tobacco in commerce; such fluctuations constitute a burden upon commerce and make the use of uniform standards of classification and inspection imperative for the protection of producers and others engaged in commerce and the public interest therein.