COMMERCIAL CANNING OF FOODS. 21 
nearly accurate than one which involves pouring the liquid upon a screen. With 
such products as tomatoes, which are cooked until they are broken to pieces or 
mushy, the weight of solids will be a little higher than if a screen were used, but 
for products which are whole or in separate pieces there will be little difference 
between the two methods. 
The acidity is uniformly expressed in terms calculated as citric acid. The results 
of the experiments apply only to California products, as in structure and behavior 
those fruits differ so much from those grown in other sections of the United States 
that inferences of similar behavior would not be warranted. Practically all the 
chemical work reported was performed by F. D. Merrill in the San Francisco Food 
and Drug Inspection Laboratory, and the last analysis by A. W. Broomell in the 
| Bureau of Chemistry. 
DETAILED CONSIDERATION OF THE VARIOUS PRODUCTS. 
FRUITS. 
GENERAL DISCUSSION. 
The first essential is that the fruits be harvested when in prime condition, handled 
with care to prevent injury or bruising, and conveyed with speed from the tree or 
vine to the factory. For canning purposes it is not necessary, and may not be 
desirable, that all fruits be as far advanced or as-soft as for eating, but they should 
be ripe, with the flavor characteristic of the ripe fruit. They should not be so far 
advanced that they will not withstand the ordinary cooking necessary for steriliza- 
tion without breaking to pieces. The prime condition for canning is that state of 
maturity in which the flavor and other characteristic qualities have been developed 
to the maximum and may be retained during sterilization. 
Bruised or damaged fruit can not be made attractive, and its use involves heavy 
waste. The proper handling of the fruit is therefore very important. Apricots, 
peaches, pears, etc., should be handled in shallow boxes which will not hold more 
than a bushel and will not admit of more than three or four layers of fruit. The 
top should be protected with cleats, so that one box can be set upon another without 
touching the fruit, thus insuring some ventilation. The small fruits—strawberries, 
raspberries, blackberries, and loganberries—are handled almost exclusively in 
chests, which are illustrated in detail in Plate II. The California packers have 
developed this part of the business to a higher degree of perfection than those in 
any other section of the country. The conical basket used in handling tomatoes in 
-the East should be abolished. The depth is too great and the shape such that the 
weight of superimposed fruit wedges the lower layers tightly together, causing 
crushing, rotting, and excessive waste. The baskets are weak, do not stack without 
bruising or cutting the fruit, and easily become disarranged or broken in shipping. 
Rapid transfer of the fruit to the factory after it has been picked is very essential. 
Deterioration in flavor and weight begins early; conditions favor the growth of 
organisms, and bacteria, yeast, and mold may develop wherever the fruits press 
together or the skins are broken. Delicate fruits, such as berries, if picked in the 
morning should be at the factory in the afternoon, or if picked in the evening should 
be delivered in the morning. Fruits with hard skins will last much longer, but the 
rule with all should be quick action. One of the disadvantages of a factory located in 
a city is the delay in receiving fruit promptly; dependence upon the surplus of the 
fresh fruit market is hazardous. 
One source of trouble and a cause of spoilage of much fruit is contamination from 
sour and moldy boxes. When a box is used several times it becomes permanently 
infected and a cause of infection by spoliage organisms. This can be controlled 
without much difficulty by having a tight room in which the worst boxes are placed 
