LEAKS IN FRUIT CONTAINERS. 
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sealed. Previous to fixing on, the margins of the lids are painted or dusted with 
a composition, which packs the space between the flanges when the lid is turned 
over the container side. 'The composition seems to vary. It consists sometimes of 
flour, dextrin, and finely powdered cork, at others of flour, dextrin, and rice starch. 
It does not form an impervious lute, possibly because the starch and flour are 
jellified by the hot water, and blown out by the internal pressure, so that the cork 
alone remains. As nearly every second tin of pears shows signs of leakage in the 
storage room, it is evident that the closure of the tins is by no means perfect. A 
rubber composition is used by some canners, and this should make a more efficient 
lute. 
Since the closing is so imperfect, one is justified in presuming that, as the can 
cools down and the contained steam becomes condensed, there is an inward pres- 
sure or vacuum, and a certain amount of air is drawn inside the tin. This is the 
root of the trouble. Any living microbe, yeast, or mould which chances to be in 
the air that is sucked in will destroy the sterility of the contents. If it is a yeast, 
much will depend upon its power of causing a fermentation of the syrup. Some 
yeasts produce little gas, others are active fermenters, and will produce 
““springers.” If the organism is an acid-producer, the tin will become a “ sour,” 
which may not be of any industrial consequence. The already acid syrup may, 
with a little more acidification, which is recognisable only by the expert,- become 
so unsuitable to the microbe that it is killed off, and the trouble does not become 
excessive. It is entirely a matter of chance as to whether any microorganism 
gets in, or that the organism, getting in, can injure the contents. In a cannery, 
where so much fruit is being dealt with, one would expect the yeasts that do 
obtain entry to be fruit yeasts, that is, the kind known as wild yeasts. It was 
with some surprise, therefore, that we found the yeasts in the majority of the 
tins to be of the cultivated or brewery type. The anomaly was, however, ex- 
plained when we learned that next door to this particular cannery there was a 
factory actively engaged in producing ginger beer. Doubtless they were using 
the brewery type of yeast, and in sufficient amount to charge the air of the 
cannery. 
While the reason for the springing can be traced to air accompanied by micro- 
scopic life being sucked into the tin while cooling, experience tells us that there is 
something more in it than can be explained by this theory: The “fly in the oint- 
ment” is this, that in the storage room about every second tin of pears shows 
signs of leaking, about every tenth tin of plums, and with peaches, apricots, and 
other stone fruits, the leaks are few in number. It is possible that the juice of 
pears has a greater solvent action upon the starch-luting of the container lid than 
other fruit juices. The subject is of interest, but there can be no doubt about the 
entry of life into the future springer subsequent to the cooking, and subsequent to 
the moment when the tins have cooled down to 170° F., or a little lower. The 
critical time begins when the tins are cold enough for the incoming yeast to be 
able to exist. ‘Thus there is an appreciable interval between the time that the 
tins leave the cooker and the entry of potentially active micro-organisms. 
The fault is not always with the lid itself. Sometimes the tin plate is 
spongy, and the syrup oozes through the microscopic holes; at other times the 
solder cementing the cylindrical wall of the container splits when the metal is 
turned in the closing machine. Again, there may be a small hole left at the 
extreme end of the seam, where the metal has been cut to give a single thickness 
of metal for bending into the hooked joint. The weakness about the process is 
in the closing of the container. ‘ 
The remedy is theoretically simple. From the time that the tins are at 
170° F. until they are cold enough to work they should be in a sterile atmosphere. 
Then the edges of the tops and bottoms should be painted with a lacquer to close 
any microscopic opening. It is not a difficult proposition, and should. be easy to 
accomplish in any cannery. : 
