SANITARY CONTROL OF TOMATO-CANNING FACTORIES. 19 



parison tests also were made on some of the unsorted stock. The 

 results of the tests from a few typical plants are shown graphically 

 in figure 1. The tests at each factory are plotted in the order made, 

 but they were not made at equal intervals. 



Factory No. 1 illustrates a case where the stock used was of very 

 poor quality but, owing to the excellence of the sorting and washing 

 systems, the decay was kept down to an average of 0.8 per cent, 

 although two or three of the tests ran rather high. 



Factory No. 2, which had experienced trouble in producing a sani- 

 tary product, adopted in 1916 a system of sorting and washing that 

 very much improved the character of the product. In this case the 

 average of the tests made for amount of rot was 0.5 per cent, with 

 one test running up to the high point — for sorted stock — of 1.7 per 

 cent. 



The table system of sorting was being followed at factory No. 3. 

 The work, however, was done so ineffectively that tests on the sorted 

 stock showed about 1.4 per cent of rot as against about 1.5 per cent 

 for the unsorted, so that there was practically no improvement. The 

 average amount of rot present was one and three-quarters times 

 as much as in factory No. 1, although the condition of the unsorted 

 stock at factory No. 1 was fourteen times as bad as at factory No. 3. 



At plant No. 4 the conditions as to sorting were found in 1910 to 

 be very unsatisfactory. Since that time extensive experiments have 

 been made, until in 1916 the improvement shown in the chart was 

 observed. The average of the seven tests made on two days was 

 about 0.5 per cent. 



The chart also shows the result of tests made during three days 

 at factory No. 5. At the beginning of the experiment the plant had 

 a number of serious defects in its sorting system. Later, several 

 changes were made in the system and the factory was operated on a 

 more approved method with striking results. The point when the 

 changes were adopted is shown in figure 1 by the letter A. The 

 average of the tests on the sorted stock prior to A was 1.26 per cent 

 of rot ; of the tests made subsequently, only 0.28 per cent. 



Data collected in many factories showed that in samples of un- 

 sorted stock examined the percentage by weight of rotten material 

 varied from practically nothing to over 30 per cent, while the aver- 

 age in the whole series was about 5.5 per cent. The percentage of 

 rot in the sorted stock (including the badly sorted as well as the 

 thoroughly sorted) varied from practically zero to over 7 per cent, 

 while the average was about If per cent. 



The percentage of rot by number was also determined during the 

 season of 1916 in most places in addition to the percentage by weight. 

 Although not so reliable as the determination by weight, it does at 



