20 BULLETIN 196, U. S. DEPARTMENT OF AGRICULTUEE. 



mine the appearance and effect upon the finished product. The proper fill for the 

 can was obtained by varying the weight from below the normal to one in which more 

 or less crushing was apparent, or by using 450, 500, 550, and 600 grams in a No. 2^ 

 can. The effect of the sirup upon the fruits was observed by using water and 10°, 

 20°, 30°, 40°, 50°, and 60° sirups. The time of processing varied from 5 to 25 min- 

 utes. Nearly all experiments were divided into two lots, one cooled and one not 

 cooled, to note the effect of this treatment. The time of the exhaust was varied 

 on some lines. Two grades of cans were used in a majority of the experiments, the 

 plain tin and the inside-lacquered, both from usual stock as supplied to packers. 



These experiments involved the preparation of fruit, weighing it into the cans, 

 and making sirups to exact degrees for more than 5,000 cans. In addition, cooper- 

 ative work was carried on with a number of canneries in the testing of sirups and in 

 the examination of the pack, the total number of cans from this source examined 

 being about 600. A record of the experimental pack and that of the product sent 

 in involved the weighing of each can as to contents, solids, and sirup, passing upon 

 the commercial grading and the effect upon the can, and in very many instances 

 a chemical examination of the sirup for solids, sugar, and acidity. A microscopical 

 examination was also made to determine the number of organisms present. Each 

 experimental lot was examined shortly after packing and again later to determine 

 the effect of standing. Direct shipments of mixed lots from the experimental pack 

 and also from commercial packs were made by express and by freight direct from 

 San Francisco to La Fayette, Ind., and one by sea from San Francisco to New York 

 and then overland to La Fayette, in order to note the effect of shipments. 



During the following winter experiments were conducted to observe the effects of 

 freezing and thawing. 



The work was continued in 1913, using some products omitted in 1912, repeating 

 experiments that seemed desirable, and increasing the scope along the lines showing 

 greatest promise of good results. The work still in progress is a determination of 

 the changes effected by standing, the effect of shipping, and of freezing and thawing. 

 The results as far as the work has progressed have been summarized in simple terms 

 under the respective fruits. The purpose has been to eliminate everything that is 

 too technical to be easily understood by the packer or the general public. 



In the examination of the details of the experimental work it may appear to those 

 whose experience has been Limited to laboratory operations that the individual 

 variations are greater than they should be. For example, the gross weight of indi- 

 vidual cans in a set of a dozen or in a case may vary as much as 20 to 50 grams when 

 the fruit has been weighed in and sirup added to make a uniform fill. A part of 

 this variation is due to the effect of exhausting and to the action of the capping 

 machine. Some fruit expands more in exhausting and floats high in the can; con- 

 sequently it will be thrown off if struck quickly by the plunger preparatory to cap- 

 ping or an excessive amount of sirup may be forced out. In the type of machine in 

 which the can spins while being crimped more or less sirup will be thrown out, 

 depending upon how free it is at the top. The object throughout all the experi- 

 ments has been to duplicate factory operations and not to attempt to make mathe- 

 matical standards. The variations indicate the advisability of taking the contents 

 of at least three cans for a composite sample in food analyses or examinations and 

 not to depend upon the contents of one can. They also show that caimers can not 

 deliver fixed net weights in cans with the present available methods. Unless other- 

 wise noted the can used is the regular No. 2^. 



The method used in draining the fruit was to cut all cans around the outside at 

 the top, leaving the end attached at one point. The end was held in place and the 

 liquid drained by inverting and slowly rotating until all free liquid escaped. This 

 method, which can be used at any place, gives quite uniform results and is more 



