WASHING AND SORTING
Washing and Sorting Equipment
A great many outfits for washing and sorting tomatoes have been placed
on the market, some of which have many good points, and others are very
inadequate. The type of washer best adapted to one plant may not be the
best for another one. If tomatoes are grown on clay ground a friction
washer is necessary, while for fruits grown on sandy soil it is very
infrequent that much friction is needed to properly clean the tomatoes.
As to sorting belts, as a rule one type will serve as well in one place
as in another. A majority of the sorting belts used are subject to many
criticisms; some are too narrow, some too short, some travel at a speed
of 100 feet or more per minute, while others move as slowly as 10 feet
per minute. The latter speed is much better than the former, although
both are extremes, 25 feet per minute being about right.
Rotary Washer
For tomatoes grown on clay ground the cylindrical rotary washer or
squirrel cage type made of 1–inch mesh heavy wire is very satisfactory.
When tomatoes come to the plant caked with clay, as they are after a
hard rain followed by strong sunshine, a friction washer of this type is
about the only thing that will clean them. This type of washer also does
excellent work on late tomatoes, and this applies to all localities. A
large percentage of late tomatoes become deeply cracked at the stem end,
and although these cracks, or fissures, usually appear to be healed
over, an examination will generally reveal the presence of mold in them,
and in many cases large tufts of mold like cotton completely filling
them. By merely passing such tomatoes through a water bath, even though
the water is thoroughly agitated by means of many inlets of compressed
air, this imbedded mold will be scarcely affected. A rotary, heavy wire,
reel washer, inclined at an angle of about 1 foot in 8, and rotating
slowly, with a heavy, sharp spray of water striking the rolling tomatoes
from the time they are dumped in until they roll out, will take out a
very large proportion of this mold, besides cleaning the entire surface
of the tomato thoroughly.
The washer should deliver about two bushels of tomatoes per minute to
the sorting belt. As the wire cylinder revolves, the tomatoes are
carried half way up the side and are then thrown back again, being
carried slowly and steadily toward the outlet. A 1½-inch pipe at the top
of the cylinder, and running from end to end, with small holes bored at
intervals of an inch, should direct a sharp, cutting shower of water on
the tomatoes as they revolve and rub each other. A fine, sharp spray
will accomplish more than a less forceful but larger stream of water
coming from a larger opening. The dirt, mold, etc. is washed through the
wire mesh into a drip pan, and thence to the sewer.
Some of the rotary washers used are of solid metal, and others
constructed of wooden slats have been used. Both of these should be
avoided, as the solid metal produces a sliding, instead of a rolling
action, and the wooden slats mold quickly and become slimy. Also, some
of the washers are slightly too narrow, and the tomatoes are so crowded
while they are rotating that many of them do not come in contact with
the wire, but merely roll on top of other tomatoes. Other washers are
considerably wider than necessary. If the tomatoes are to be fed to the
belt at the rate of 2 bushels per minute, a reel (squirrel cage) washer
2 to 2½ feet in diameter, and about 8 feet long, having an inclination
of about 1 foot in 8, and revolving at about 20 revolutions per minute,
will usually give satisfactory results. These are the figures
recommended by Mr. Howard of the Bureau of Chemistry, who has made a
very extensive study of the efficiency of rotary washers.
By having the tomatoes thoroughly clean, with no mud and scarcely any
mold adhering to the surface when they drop on the sorting belt, the
amount of sorting required is not only greatly lessened, but the spots
of black rot and other forms of decay show up prominently on the
surface.
It is important that the reel deliver the tomatoes to the sorting belt
at a uniform rate, which is seldom done when the crates are dumped into
the reel without any system of timing them. At present a hopper for
feeding the reel is being experimented with, and it is hoped that it
will be an improvement over the uncontrolled system that is now used.
The chief objection made to the reel cylinder is that when tomatoes are
overripe, having been shipped a long distance, or held at the factory
for a day or two, the rubbing action of the wire on the tomatoes, and of
the tomatoes against each other, is too severe, and considerable tomato
substance is lost by being forced down through the wire mesh by the
sharp sprays of water from overhead. The loss in this case is not nearly
as great as would be imagined, and what tomato substance is thus lost
should be discarded anyway, as it is so soft that in all probability the
fiber is permeated with growths of mold, yeasts, and bacteria, which no
amount of washing would eliminate.
Water Bath With Compressed Air
The reel washer is not so common in the east as in the west, and the
reason is, as previously stated, that during the greater part of the
season at least, tomatoes grown on loose, sandy soil can be washed
satisfactorily by other devices which are less cumbersome and can be
more easily rigged up. One of these devices which is in satisfactory
operation is a shallow water bath through which the tomatoes pass on a
chain carrier, and in which the water is kept “boiling” (that is, it has
the appearance of boiling) by compressed air which is forced into the
water bath through small pipes, and at a number of different places. The
tomatoes are thus bounced around and knocked against each other in a
very lively manner and receive a thorough cleansing. It is very
doubtful, however, if this device would give such good results on
tomatoes that had clay baked hard on the surface, or on those which had
mold deeply imbedded in cracks at the stem end.
Importance of Agitation
It is always advisable to wash the tomatoes before sorting them, as it
makes the sorter’s work so much easier. After the tomatoes leave the
sorting belt they can pass under a few strong sprays which will put on
the finishing touches. Warm or hot water is sometimes used in washing
tomatoes, but cold water does the work just as well. Neither will
accomplish much more than wetting the surface unless the tomatoes are
agitated. Some devices which I have seen are almost worse than nothing,
as they merely consist of a long water bath through which the tomatoes
are conveyed by means of a large worm or helicoid. The tomatoes are not
only washed insufficiently, but are contaminated by rubbing against the
surface of the worm, which soon becomes coated with a film of mold, and,
being enclosed in a cylinder, this worm cannot be cleaned as it should
be. It is essential that every part of the equipment with which the
tomatoes come in contact be readily accessible to the brush and the
steam hose. Mold accumulates very rapidly, clings very tenaciously to
the surface on which it grows, and a damp surface in a dark place is
ideal for its growth.
Plain Sorting Belt
The type of sorting belt used most commonly is the ordinary plain wire
or metal belt 18 to 24 inches in width and about 10 to 12 feet in
length. Canvas belts are also used quite frequently, but the packer can
now obtain wire belts of such strong, sturdy construction that they give
scarcely any trouble and are very satisfactory in every way. Eighteen to
twenty inches has been found to be about the best width.
Number of Sorters
The number of sorters which should be employed on each belt depends upon
whether they are going to do both the inspecting and trimming, or the
inspecting alone, and also upon the rate at which the tomatoes are fed
to the belt, the length of the belt, and the quality of the fruit. Some
pulp makers prefer to feed the belt at a uniform rate regardless of the
quality of the fruit and to vary the number of sorters, employing about
14 or 16 to a belt when the quality is poor, and about half that number
when the tomatoes are almost entirely sound and need very little
trimming done to them. Others prefer to use the same number of sorters
and trimmers on the belt all the time and to vary the speed of the belt
according to the quality of the fruit, using a variable speed
transmission for this purpose. When running on solid fruit, with very
little decay, the maximum speed can be employed, say 40 feet per minute,
and when running on stock that is not so good the speed can be decreased
to about 10 feet per minute.
The Bureau of Chemistry advises very strongly against the practice of
having the women who do the inspecting do the trimming also. They
contend that inspecting and trimming should be two distinct and separate
operations and each should be done by a different set of women. By this
method the women on the sorting belt merely pick out all the tomatoes
which are imperfect and throw them into receiving boxes which are
attached to the framework of the sorting belt by a bracket, there being
about four of these boxes to a table—two on each side. One or two women
stand at each receiving box, pick out the defective tomatoes from this
box, and trim out the bad part, which is dropped into a chute, which
directs the material down to a drain underneath the table through which
is flowing the waste water from the rotary washer. This stream, properly
placed, has sufficient current to carry away the waste matter. The
trimmer throws the good part of the tomato back on to the sorting belt.
By using this system there is no lugging of boxes or buckets back and
forth from the sorting table.
This method, which is the one approved by the Bureau of Chemistry,
accomplishes the work more thoroughly than can be done if the inspecting
and trimming are all done on the sorting belt by the same set of women.
The minimum cost of sorting and trimming in this manner is from 2 to 3
cents per bushel, according to the government figures.
If the women on the sorting belt are to be used for both inspecting and
trimming, a longer belt should be used than if inspecting alone is to be
done. About 2 feet of belt should be allowed to each sorter.
Tomato Turning Device
[Illustration:
Fig. 1.—Tomato turning device on sorting belt.
]
There is another feature which helps greatly in sorting, and that is a
tomato turning device, which is illustrated in Figure 1. This device
turns a very large percentage of the tomatoes if they are fed to the
belt properly, that is, if they are spread out evenly and are not too
thick on the belt. The turning device allows them to be inspected from
all angles, and is described in Bulletin 569 of the U.S. Department of
Agriculture as follows:
“For an apron (sorting belt) 18 inches wide, 14 pieces of ¾ inch iron
pipe (1 inch outside) were cut, each piece about 7 inches long. About
one-half inch from one end of each piece a hole was drilled through the
pipe large enough to permit of the pipes being strung on a ¼ inch steel
rod. In order to insure freedom of movement, a thin washer was placed
between each pipe and the one next to it. The whole set was then
suspended by means of the steel rod across the sorting apron with the
lower ends one-half inch above the apron. A back-stop rod is put in
behind the set to prevent the pipes from swinging back past the center.
This was found necessary to prevent them from swinging so far back as to
strike and gouge the oncoming tomatoes. * * * In operation the weight of
the pipes is sufficient to roll the tomatoes over as they pass under.”
“In order to obtain satisfactory operation it is most important that the
tomatoes do not cover more than 50 per cent of the apron area, otherwise
they do not have room to turn properly. A test at one plant showed that
70 to 80 per cent of the tomatoes were turned each time they passed
under a set of the pipes. It was found also that this turning device
worked better on the open metal apron than on the canvas or rubber type,
owing to the fact that the tomatoes slipped badly on aprons made of
canvas or rubber.”
Divided Sorting Belt
There is a modification of the plain belt which is in use at several
plants, and which some operators like very much. This belt is
illustrated in Fig. 2. Note that it is divided into three partitions by
two boards which run lengthwise. These boards are about 3 inches high
and are raised a fraction of an inch above the belt so as to allow the
belt to slide under them easily. At the head of the belt the board
partitions connect in a “V”. The tomatoes strike this V and are guided
into the two outer channels, where they are given a hasty inspection by
the first four sorters, who throw all those which are perfectly sound
into the center partition. As the tomatoes which remain in the two
outside partitions pass down to the rest of the sorters they are
inspected, the bad parts cut out, and the good part thrown into the
center partition. The bad parts which are cut out are left on the
outside partitions, where they are carried along into two waste barrels,
which are provided for this purpose at the end of the belt.
[Illustration: FIG·2 DIVIDED SORTING BELT]
By using this method no tomatoes but good ones can go through unless bad
ones are carelessly thrown into the center partition and every tomato
HAS to be picked up. Of course, some bad tomatoes are thrown into the
center carelessly, where they will remain unless taken out by the final
inspector, who is supposed to watch this. However, the number which are
thus thrown in are not great if the first four women on the belt are
trained as they should be—that is, to only throw those tomatoes in the
center which a hasty inspection shows are perfectly sound, and to leave
all doubtful ones pass by.
By this method each good tomato is only inspected once, which is not the
case with any of the other systems, and in that respect it is more
efficient. One good tomato is not picked up, looked at, and placed on
the belt again by a number of different sorters. When a tomato is picked
up by a sorter some disposition is made of it at once. If good it is
tossed in the center and is never looked at again except by the final
inspector. If bad, the good part is thrown in the center and the bad
allowed to remain on the outside, to be conducted to the waste barrel.
All the sorters except the first four can spend their entire time
working on tomatoes which need to have bad parts cut out of them.
The main objection which is made to the divided belt system is that the
first four women get careless and throw unsound tomatoes into the center
partition and they are never looked at again. However, if care is used
in the selection of these women, and a reliable sorter is placed at the
end of the belt to inspect the center partition before it leaves the
belt, such carelessness can be checked and held down to a minimum.
Another objection that is advanced is that there is the possibility of
partly good tomatoes going into the waste barrels due to the fact that
the women might not always keep up on them. In my experience with the
system I have had practically no trouble in this regard. If a long belt
is used, as many trimmers as desired can be put on, and the belt can be
slowed down or the rate at which it is fed slowed up if the tomatoes are
running particularly bad. Then, in extreme cases, it is always possible
to have someone go over the waste barrels before they are dumped.
An average grade of tomatoes can be handled quite rapidly by the divided
belt system. Some packers who have used it several seasons like it very
much, and an analysis of their product will generally show a low count
of molds, yeasts and spores, and bacteria. I understand, also, that
other packers that have used the method have discarded it.
Sorting
By far the greater part of the trouble packers have with their goods not
complying with the government regulations as to molds, yeasts and
spores, and bacteria is due to inadequate sorting. At least ninety per
cent of this trouble could be overcome right at the sorting belt.
Packers often say they can’t understand why the mold is running high on
their pulp and catsup, as they are sorting their tomatoes carefully.
However, the chances are ten to one the trouble is they are not sorting
them carefully enough. One who has not had much experience managing help
on the tomato sorting belt would imagine that almost any woman could
step up there and sort out the good tomatoes from the bad, and know what
to cut out, and what not to cut out. But such is not the case. The
tomato sorters must be instructed. Someone who is competent to do so
must work with each one of them and show them just what is a good tomato
and what is not. Otherwise they will be spending part of their time
cutting out black, fibrous growths on the surface of the tomatoes which
are absolutely normal and entirely free from molds, etc., and allowing
tomatoes to pass by them which have black spots on the surface no bigger
than a dime, but indicating to the trained eye that probably half of the
tomato is eaten up with black rot. They will allow a tomato to pass by
which is cracked open, and the edge of the skin on each side of the
crack will be as white as a piece of paper. Unless they are instructed,
they may not realize that this is mold, and they certainly will not
realize the amount of damage a small percentage of tomatoes like that
can do. They know nothing about mold counts, but most women can be
impressed with the importance of watching for moldy streaks and spots in
mashed and split tomatoes, and the importance of eliminating every bit
of tomato tissue that is so effected.
Every sorting belt should have a boss—a competent sorter who knows his
or her business, and who stands at the end of the belt and inspects the
tomatoes just as they are about to leave the belt. This person can order
the speed at which the tomatoes are fed to the sorters increased or
decreased according to the quality, can see just what form of decay is
predominating and caution the sorters to watch out for it, can see the
mistakes that are being made in the sorting and try to correct them, and
in addition can throw out into a receptacle such bad tomatoes as have
passed by the sorters so that they can be sorted over again. It is not
safe to put a bunch of women on the sorting belt with no one in
authority who is on that particular job every minute, and expect an
entire day’s run to come within the government limits.
Forms of Decay
There are many forms of rot, but the most common are the black rot, soft
rot, and the mold growths in cracked tomatoes, either those which have
cracked deeply around the stem end during their growth, or have been
cracked or mashed in shipment. Just as soon as the skin is broken,
either in a natural or unnatural way, molds start growing on that broken
surface immediately, and develop very rapidly.
There is also the brown spotted tomato, which is not so common, but
which has been very bad in some localities. I remember one field of
tomatoes in southern Ohio several years ago which was absolutely
worthless for canning purposes, due to the fact that practically all of
the tomatoes were covered with brown spots, and under each one of these
spots was a lump of white mold and mold spores. This field was plowed up
before half of the tomatoes were picked, as the pulp plant which had
contracted them refused to receive any more after having cooked several
batches of pulp on which the mold ran very high due to this condition,
which had never been met with before. The brown spots were soft and
concave, and if once the character of the spot was fixed in the memory
one could never fail to quickly detect that type of tomato if it was run
across again.
The disease appeared in both central and southern Indiana the following
year and I sent samples of the tomatoes to the Department of Agriculture
at Washington and to the Indiana state experiment station, but it was
new to them and they had no remedy for it. Whether it has appeared since
I do not know, but it was very bad while it lasted. It is almost
impossible to sort such tomatoes, as the spots are so numerous on the
surface, and every spot would have to be cut out. When the spots are
small, as they frequently are, they are very apt to pass by the sorters
unnoticed, or at any rate considered harmless, but it doesn’t take many
bushels of such tomatoes to send a batch over the limit in mold count.
Extremely soft spots which will yield to very slight pressure with the
finger are usually receptacles for the growth of yeasts and bacteria and
should be cut out. Nine times out of ten such spots are offensive to the
nose when the skin of the tomato is broken. However, one quickly learns
to pick them out by sight.
It is important that the sorting belt be well lighted with 100–watt
lamps overhead provided with large reflectors. On dark days good sorting
is impossible unless the belt is adequately lighted, and, of course, for
sorting in the early morning or late evening adequate light is
absolutely essential.
Cleanliness of Equipment
To dwell upon the necessity of thoroughly cleaning all washing and
sorting equipment each night, as well as to frequently change the water
in water baths, in case a water bath is used, would seem almost
unnecessary, yet there are many packers who do not comprehend the
trouble that can be caused by inadequate cleaning of the washing,
sorting, and conveying equipment.
Does the sorting and washing equipment in every pulp plant impart a
clean, fresh, sweet smell when the morning’s work is begun? It does not,
and the reason is that it was not properly cleaned the night before.
Those surfaces which were easy to get at and which are easily seen in a
hasty inspection are clean, of course, but how about the dark corners
and almost inaccessible places that are hard to clean? Can you run your
fingernail over the surface of one of the bucket conveyors, or
“flights,” for example, and scrape off a thin, slimy film? If you can,
you can be sure it is mold, and that the only way to get it off is with
a very stiff brush—even a wire one may be necessary—hot water, and soda
ash. If the bucket conveyors or “flights” are covered with a thin film
of mold, the tomatoes will carry along a small part of this mold with
them every time the conveyor is used, and as fast as the mold is rubbed
off the conveyor by the tomatoes more mold will grow on again.
The same care should be taken with this equipment as is given to the
equipment in a milk bottling or condensing plant. My experience has been
that the only safe way to check up the thoroughness of the cleaning job
is to go over it with a spot light, with particular attention to the
most inaccessible parts, and to do everything possible to make every
part of the equipment accessible.
Molds, Yeasts and Spores, and Bacteria
An understanding of the nature of molds, yeasts and spores, and bacteria
is very helpful to any packer. A knowledge of the rapidity of their
growth and the conditions under which they multiply most rapidly is also
helpful. The average packer has a very vague idea of this subject, yet
it is easy of comprehension. In CHAPTER VII a discussion of it will be
found, which it is hoped will help to clear up the misty atmosphere
surrounding this subject, and in the same chapter the government
attitude toward micro-organisms is also discussed.