2 BULLETIN 581, U. S. DEPARTMENT OF AGRICULTURE. 
reached largely by such experiments. At that time very few tests 
had been made to correlate the amount of rot by weight with the 
microscopical counts. In the present discussion, therefore, the. 
results obtained by visual inspection are considered first. The other 
series, that in which the percentage of rot was estimated, is discussed 
later (p. 8). 
RELATION BETWEEN VISUAL INSPECTION AND MICROSCOPICAL 
EXAMINATION. 
Tables 1 to 6, inclusive, and Tables 9 to 12, inclusive, show that a 
fairly concordant relationship exists between the character of stock 
as determined by visual inspection and the microscopic counts on 
the final product. In Bureau of Chemistry Circular 68 it was sug- 
gested that by good, sanitary practice the mold count could be kept 
down to 25 per cent or less, the yeast and spore count to 25 or less, per 
1/60 cubic millimeter and the bacteria per cubic centimeter to 25 mil- 
lion orless. In only one instance in Tables 1 to 6 (Table 1, S 32) are 
these suggested limits exceeded on stock which to visual inspection 
appeared acceptable. In thissample the bacteria ran somewhat higher 
than is usual for passable stock. These results show that good stock 
properly handled almost never runs high in microorganisms. 
In general, high counts of microorganisms are obtained on products 
made from stock which by visual inspection would be judged as 
objectionable or from stock which has been improperly handled. 
There seem to be, however, more exceptions to this rule than: to 
that governing the microorganism count on products made from good 
stock. In three or four samples the counts are comparatively low 
on stock which to visual inspection appeared dubious. The few 
such exceptions which from time to time occur do not modify the 
fact that high counts of organisms indicate unmistakably that the 
stock used was in bad condition or that it was handled in an insani- 
tary manner during manufacture. Either of these causes furnishes 
sufficient ground for condemnation of the product. 
TOMATO PULP. 
The average of the counts on pulp from stock which appeared 
acceptable from a visual inspection (Table 1) is as follows: Molds in 
8 per cent of the fields; yeasts and spores, 8 per 1/60 cmm; bacteria, 
5,900,000 per cc. Table 2 gives the results of counts on pulp made 
from unacceptable or questionable stock. Taking averages of the 
counts in this table, excluding samples of questionable character, 
the following results are obtained: Molds, 51 per cent of the fields; 
yeasts and spores, 51 per 1/60 cmm; bacteria, 77,900,000 per ce. 
