Allen Paul W. Industrial Fermentations

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TOMATO PRODUCTS 325

"Observe each field as

to the presence or absence of mold filaments

and note the result as positive or negative. Examine at least 50 fields,

prepared from 2 tir more mounts. No field should be considered

positive unless the aggregate length of the filaments present exceeds

approximately one-sixth of the diameter of the field. Calculate the

proportion of positive fields from the results of the examination of all

the observed fields and report as percentage of fields containing mold

filaments.

Yeasts and Spores (Tentative).

"Fill a graduated cylinder with water to the 20 co. mark, and then

add the sample till the level of the mixture reaches the 30 cc. mark.

Close the graduate, or pour the contents into an Erlenmeyer flask,

and shake the mixture vigorously 15 to 20 seconds. To facilitate

thorough mixing the mixture should not fill more than three-fourths

of the container in which the shaking is performed. For tomato sauce

or pastes or produote running very high in the number of organisms,

or of heavy consistency, 80 cc. of water should be used with 10 cc.

or 10 grams of the sample. In the case of exceptionally thick or dry

pastes it may be necessary to make an even greater dilution.

"Pour the mixture into a beaker. Thoroughly clean the Thoma-

Zeiss counting cell so as" to give good Newton's rings. Stir thoroughly

the contents of the beaker with a scalpel or knife blade, and then,

after allowing to stand 3 to 5 seconds, remove a small drop and place

upon the central disk of the Thoma-Zeiss counting cell and cover

immediately with the cover glass, observing the same precautions in

mounting the sample as before. Allow the slide to stand riot less

than 10 minutes before beginning to make the count. Make the count

with a magnification of about 180 to obtain which the following com-

binations, or their equivalents, should be employed; 8 mm. Zeiss

apochromatic objectives with X6 Zeiss compensating ocular, or an

8 mm. Spencer apochromatic objective with X10 Spencer compensating

ocular with draw tube not extended.

"Count the number of yeasts and spores on one-half of the ruled

squares on the disk (this amounts to counting the number in 8 of the

blocks, each of which contains 25 of the small ruled squares. The

total number thus obtained equals the number of organisms in 1/60

cmm. if a dilution of 1 part of the sample with 2 parts of water is

used. If a dilution of 1 part of the sample with 8 parte of water

is used the number must be multiplied by 3. In making the counts

the analyst should avoid counting an organism twice when it rests on

a boundary line between 2 adjacent squares.

Bacteria (Tentative).

"Estimate the bacteria from the mounted sample but allow the

sample to stand not less than 15 minutes after mounting, before oount-

ing. Employ a magnification of about 500

which may be obtained

by the use of an 8 mm. Zeiss apochromatic objective with an X18 Zeigs

326 INDUSTRIAL FERMENTATIONS

compensation ocular with draw tube not extended or an 8 mm. Spencer

apoehromatic objective with an X20 Spencer compensating ocular

with a tube length of 190, or their equivalents. Count and record the

number of baoteria in a Bmaii area consisting of 5 of the small sized

squares. Move the slide to another portion of the field and count the

number on another similar area. Count 5 such areas, preferably 1

from near each corner of the ruled portion of the slide and 1 from

near the center. Determine the average number of bacteria per area

and multiply by 2,400,000, whioh gives the number of bacteria per

cc.

If a dilution of 1 part of the sample with 8 parts of water instead

of 1 part of the sample with 2 parts of water is used in making up

the sample, then the total count obtained as above must be multiplied

by 7,200,000.. Omit the micrococci type of bacteria in making the

count."

The importance of sorting in the manufacture of tomato products

has been emphasized by Howard and Stephenson: Tfrey say: "A

careful consideration of the causes of failure in making c&an, sound,

sanitary tomato products shows clearly that more d&Seulty is ex-

perienced in effecting satisfactory washing, prompt handling, and

efficient sorting than in any of the other phases of the manufacturing

process. Sorting is the most important of these operations, in which

the judgment of the workman plays a considerable part. Satisfactory

washing is largely a question of proper operation of a meohanicaj

device. This may be said of many of the other operations about the

factory, but so far no mechanical contrivance for separating the de-

cayed from the good parts of the tomatoes has been placed upon the

market. This operation must still be performed principally by hand.

Although some washers, if properly constructed and operated, will

assist in removing the badly soft-rotted tomatoes, efficient hand sort-

ing must be employed if a uniformly good, -sound product is to be

obtained.

"Experience has shown that in factories where the tomatoes axe

used only for peeling stock and where all the trimmings are thrown

away sorting is an unnecessary expense. In the making of pulp of any

kind, however, efficient sorting is absolutely necessary. Otherwise

there can be no assurance of producing a uniformly sound product

with low counte of microorganisms.

"The conditions observed and the results obtained in various

factories' show that there is little, if any, choice between sorting the

tomatoes before and after washing. Some of the best, as well as some

of the poorest, results were obtained in factories where one or the

other of these methods was employed. Approximately two-thirds of

the plants visited during the seasons of 1915 and 1916 that did any

sorting at all were using the wet method, and one-third the dry method.

In order to remove clinging pieces of partially decayed tomatoes, the

tomatoes always should be subjected to a washing or rinsing after

sorting, even though the principal washing has been done before

sorting."

TOMATO PRODUCTS 327

REFERENCES ON TOMATO PRODUCTS.

Bertarelli, E., and Marcheli, M. Bacteriological

ftVH.Tninn.tinn

of tomato prod-

ucts.

Ami. Ig. (Rome), 30, 309-322, 1920. Aba. in Exp. Sta., Reo. 44,

11,

1921.

Bitting. A. W. Status of the tomato and its products. Canning Age, 2. No.

11,

6-6. Nov. 1921. .

Darling, C. A. Methods of determining the number of microorganisms in

tomato products. New York (Geneva), Agr. Expt. Sta., Tech. Bui. No. 91.

Duckwall, E. W. Semi-monthly report of National Canners' Laboratory. The

Canner, % No. 18, May 6, 1915.

Duckwall, E. W., 1905. "Canning and preserving with bacteriological technique."

(Text.)

Duckwall, E. W., 1899. Bacteriology of canned foods. (Text.)

Howard, B. J., 1911. Tomato ketchup under the microsoope. Cir. 68. Bur.

Chem., U. S. D. A.

Howard, Burton J.

and Stephenaon, C. H., 1917. The Banitary control of tomato

canning factories. U. S. D. A^ Bui. 569.

Miller, H. M. Modification of Howard's method for counting yeasts, spores,

and bacteria in tomato products. Jour. Ind. and Eng. Chem., 12, 766-769,

1920.

Vincent, C. The direct or Breed method for counting bacteria in tomato

catsup, pulp, or paste. Jour. Bact., 3, 183-186. 1918.

Chapter 25.

Fruit Juices and Beverages.

The science of the preservation of fruit juices is only in its infancy.

The great value of fruit juices in any diet is only partly appreciated.

Great quantities of valuable fruit juices go to waste each year while

at the same time few people are free from injury to health due to too

little fruit or fruit products in the diet.

The slowneBs with which comparatively cheap fruit juices have

come into use is due largely to the lack of satisfactory methods of pre-

serving fruit juices without alteration in flavors.

Grape juice is one of the most important fruit juices of commerce.

According to Munson, Concord grape juice must contain 20.37%

total fiolids, .663% acids as tartario acid, 18.54% grape sugar, .027%

phosphoric acid and .55% cream of tartar, and no alcohol. In the

pressing out of the juice of the grape, many of the organisms existing

on the

HTHPH

and steins find their way into the expressed juice and if

allowed to remain will ferment it. While refrigeration retards this

fermentation still it cannot be depended on to prevent it.

Grape juice is usually preserved by holding for a short period of

time at the temperature of 175° F. A temperature higher than

175° F. begins to affect the flavor giving it a slightly cooked taste.

Pasteurization of the grape juioe is effected in vat pasteurizers or in

continuous typeB.

Loganberry juice is a product which has come into the market

recently but the industry is growing rapidly. It is said that the juices

of loganberries grown in Oregon and Washington differ from that

of the loganberries of California in that the northern berries have a

higher acid content. Because of the naturally high acid content,

loganberry juice has to be diluted and sweetened for consumption,

however this high acid content is very important in aiding the steriliza-

tion of the juice.

Because of the love of molds for high acid berry juices, logan-

berries must be crushed and expressed as soon as possible after picking.

Apple juice or cider is often considered as only vinegar making

material but is in reality one of our most valuable fruit juices and

there is increasing activity shown in marketing it as a summer drink.

However, there are certain difficulties in its preservation. It is hard

to sterilize and preserve cider without preservatives. Heating cider

to the temperature which would insure preservation in containers is

inolined to give a cooked taste.

328

FRUIT JUICES AND BEVERAGES 329

Sour apples contain .5^> or more of malic acid while sweet apple

juice contains but half this amount. The chief constituents of apple

and pear juices are sugar, tannin and malic aoid.

H. C. Gore says: "It is possible to sterilize apple juice in wooden

containers, the product remaining sound for at least six months under

actual observation. The precautions which must be taken to insure

this are as follows: First paraffin the containers on the outside, then

sterilize, and fill with juices heated to between 149 degrees and 158

degrees F. (66 degrees to 70 degrees C.); seal, taking measures to

relieve the vacuum produced by the contraction of the juice on cooling

by filtering the air through cotton. Twenty-four ten-gallon kegs

successfully stood a severe shipping test, showing no loss due to fer-

mentation of the juice. The juice so prepared was found to be pala-

table, and acceptable as a summer drink. (2) It is demonstrated that

apple juice can be successfully sterilized in tin containers, using the

type of tin can sealed by the mechanical process, excluding all metals

from contact with the juice except the tin of the can. Where lacquered

cans are used the contamination with tin was reduced about

one-half.

Apple juices were canned and sterilized by heating in a hot water bath,

up to the temperature of 149 degrees F. (65 degrees C.) for a half

hour, and then were allowed to cool. These juices possessed only a

slight cooked taste due to the heating and retained much of their

distinctive apple flavor. It was found that from finely flavored apple

juice a first-class sterile product could be made, while a poorly flavored

apple juice yielded an inferior product. The process conditions men-

tioned were not quite thorough enough to sterilize all of the varieties'

canned. A slight increase in the temperature or time of processing,

or both, should be made, the temperature not to exceed 70 degrees C.

(158 degrees F.) in any oase. (3) The best treatment for sterilizing

in glass was found to consist in heating for one hour at 149 degrees F.

or for one-half hour at 158 degrees F. Heating for one hour at 158

degrees did not produce marked deterioration in flavor, a half hour

being allowed in all cases for the juice to obtain the temperature of

the water bath. (4) It was shown that the great bulk of the insoluble

material naturally contained in apple juice can be removed by means

of a milk separator. (5) It is possible to carbonate the juice slightly

before canning or bottling, thus adding a sparkle to the product. A

flavor foreign to fresh apple juice is also added, however, and uncar-

bonated sterile juice will resemble fresh apple juice more closely.

Carbonating by the addition of water charged with carbon dioxide

was considered by some to injure the flavor, lessening the characteristic

fruit flavor by dilution. In the opinion of others a heavy, rich juice

was improved both by the charge of carbon dioxide and by the con-

sequent dilution. Experiments indicated that the danger of contami-

nation by mold growths was lessened by maintaining an atmosphere

of oarbon dioxide above the surface of the juice after opening. (6) It

is demonstrated that benzoate of soda in quantities varying from 0.03

to 0.15% (0.1% being the maximum temporarily permitted by the food

330 INDUSTRIAL FERMENTATIONS

regulations), while it checks the alcoholic fermentation, allows other

organisms' to develop (notably the acetic acid ferment), whereby the

palatability of the product as a beverage is destroyed."

It is the acid content of fruit that most aids their preservation by

heat. Generally speaking the greater the acid content the less the

exposure to heat required to sterilize. Biglow and Dunbar designate

the kind of acid in fruit juices as follows:

Apple Maliqalone

Cherry Malic alone

Plum Malic alone

Banana Malic alone

Peach Malic alone

Persimmon Malic alone

Cantaloupe Citric alone

Cranberry Citric and malic

Currant Citric and malic

Gooseberry Citric and malic

Pear Malic alone

Quince Malic alone

Watermelon Malic alone

-Cayser reports that pineapple contains citric acid alone.

Very delicious fruit juices are prepared from blueberries, cherries,

and gooseberries by expelling the juice from the fruit and pasteurizing

it on two or three consecutive days at 155° F. for 30 minutes. In the

preparation of these fruit juices it is important that the fruit be washed

well before pressing and that the utensils used in bottling and the

bottle be sterile.

The Preparation and Preservation of Fruit Juices.

In a study of the possibilities of preparing and preserving the

juices of such fruits as the orange, lemon, 'pineapple, strawberry and

blackberry, H. C. Gore in the U.SJDA. Bulletin, says:

"The experiments developed the fact that ordinary methods of

sterilizing fruit juices' by heat could be successfully applied to but

a limited number of the special fruits such as the black raspberry,

blackberry, black currant, sour cherry, and peach. In the case of the

juices of the strawberry, red raspberry, red currant, pineapple, and the

citrus fruits, as well as apple cider, sterilization by heat caused loss in

flavor, and where kept after heat sterilization the juices of these fruits

tended to lose color or flavor or both.

"In the case of strawberry, apple, and other juices which are

greatly injured in distinctive flavor by being heated, it is possible to

retain the flavor satisfactorily by keeping the juice in freezing storage

at a temperature of 14 degrees F. Although certain juices, as pine-

apple and orange, are not greatly injured in flavor by sterilization,

they change in flavor and color upon being kept at ordinary tem-

peratures after sterilization. Keeping such juices in cold storage at

from 32 degrees to 36 degrees F. causes satisfactory retention of the

FRUIT JUICES AND BEVERAGES 331

oolor and flavor. Another cold-storage method of general application

to fruit juices, and one particularly "valuable for fruit juioes, the dis-

tinctive characters of which are injured by heat, is the method of con-

centrating by freezing.

"Juices of oranges, lemons', and pineapples darken greatly in color

if sterilized and subsequently kept in contact with atmospheric oxygen.

Satisfactory color retention can here be had by sterilizing and keep-

ing the juices free from atmospheric oxygen, which is most conveni-

ently effected by carbonating slightly and sterilizing them in carbon

dioxid.

"Juices of red and black currants, blackberries, black raspberries,

sour cherries, and peaches may easily be successfully prepared on the

large scale by the methods used for the preparation of grape juice,

as they retain their characteristic properties well on being sterilized

and stored away. Strawberry juice and red raspberry juice are not

suited for preparation on the large scale because of the readiness with

which the distinctive colors and flavors change. Huckleberry juice

is somewhat charaoterless. Pineapple juice requires special methods

for its successful preparation not necessary in case of other juices.

Its preparation on the commercial scale, however, is of marked

promise.

"Satisfactory methods for the preparation of lemon and orange

iuice.8 have not been developed. The peculiar change in flavor of

lemon juice stored after sterilization, even at low temperatures, is an

obstacle to be overcome before the preparation of the juice on the

large scale can be considered advisable. The problem of preparing

orange juice is not without promise. It is not unlikely that highly

specialized methods in which cold storage will play a prominent, if

not dominating part, will be required."

Gore says concerning cold storage of fruit juices: "Apple juice,

cooled quickly after pressing to 32 degrees F. and stored at this

temperature, will keep for from 6 weeks to three months before it

ferments sufficiently to be considered hard or sour. Unpublished ex-

periments on the keeping of raw orange juice at from 32 degrees to

35 degrees F. show that its flavor deteriorates quite rapidly. An

unfavorable feature of storage of raw fruit juices at from 32 to 35

degrees F. is the development of molds at juice surfaces. It is not

improbable that simple measures for the suppression of the mold

growths could be successfully used, as for example, keeping the

containers entirely filled, or keeping the juice surfaces well blanketed

with a layer, of oarbon dioxid, or possibly using ultraviolet light. It

seems probable, however, that cold storage of freshly expressed juices

at from 32 degrees to thirty-five degrees F. is of but limited applica-

tion, as the activities of microorganisms are not sufficiently held in

check."

Gore studied the retention of colors and flavors during preparatory

heating and storage of fruit juices. He says:

"The extent to which color and flavor were retained on keeping the

332 INDUSTRIAL FERMENTATIONS

juice after sterilization varied greatly in the juices from the various

fruits

"In strawberry juice the brilliant red color of the freshly sterilized

juices in all cases faded greatly and further flavor losses occurred.

Sterilization and subsequent keeping in carbon dioxid were not effective

in securing color retention.

"Red currant juice very gradually lost in distinctive color and

flavor on being kept at room temperatures after sterilization and

keeping in carbon dioxid was not effective in securing either color or

flavor retention. Cold storage at from 32 to 35 degrees F. was found

to be a very satisfactory means of controlling color and flavor changes.

"The distinctive colors and flavors of black currant, blackberry,

and black raspberry juices were satisfactorily retained during pro-

longed periods' at common storage. The flavor of blackberries was,

however, distinctly less well retained than that of black currants or

black raspberries, though it did not undergo a perceptible change

during a storage period of six months.

"In the case of red raspberries the distinctive color and flavor were

•poorly retained, even on keeping the juice in carbon dioxid in cold

storage at from 32 to 35 degrees F.

"When sterilized and subsequently kept in carbon dioxid the dis-

tinctive color of pineapple juice remained practically unchanged.

When exposed to atmospheric oxygen at juice surfaces during and after

sterilization, marked darkening occurred. Change in color was also

found to be greatly, though not wholly, retarded by keeping the juice

in cold storage at from 32 to 35 degrees F. On keeping the juioe at

ordinary temperatures the distinctive pineapple flavor gradually

lessened, though the juices remained recognizable as pineapple. By

keeping in cold Btorage at from 32 to 35 degrees F. flavor ohange was

almost wholly prevented.

"The distinctive colors and flavors of peach and cherry juices were

quite well retained while kept at room temperatures. Huckleberry

juice, hot pressed, lost in flavor on keeping.

"Lemon juice darkened in color if sterilized and kept in the

presence of atmospheric oxygen, though the color was satisfactorily

retained when the juice" was sterilized and kept in carbon dioxid or

in vacuum. In all cases an off-flavor, designated as a 'bottled lime-

juice' flavor, appeared in the lemon juice after it had been kept for a

time after sterilization, even though in cold storage at from 32 to 35

degrees F."

Beverages are generally thought of as belonging to several different

classes as alooholic and non-alcoholic, carbonated and non-carbonated,

fermented and unfermented, etc.

Some of the most popular of summer beverages are called pops.

Pops are defined by J. 0. La Back as "non-alcoholic, artifioially car-

bonated beverages sold in the original bottles and intended to be con-

sumed as soon as opened."

Pops are made with different flavors as, strawberry, orange, pine-

FRUIT JUICES AND BEVERAGES 333

apple, lemon, raspberry, cream, and cherry. The rootbeers and ginger

ales are kinds of pops. La Back speaks of beverages of the coca cola

type containing caffeine and flavoring from the cola plant as pops

According to W. B. Pumell the bacteriological content of pops is

generally small due to the germicidal condition. In summing up his

investigation of the bacteriological condition of pops he gives the

following conclusions:

"1.

The bacterial count of the finished products, put out by soft

drink manufacturers, does not give a correct index into the sanitary

conditions existing.

"2.

That carbonic acid gas is antiseptic and germicidal to a de-

cided extent,, but since all microorganisms are not inhibited or killed,

it cannot be relied upon as a sanitary safeguard.

"3.

That most of the waters used in making the product are con-

taminated and unfit for use.

"4.

That the bottles, when ready for filling, show a lack of steriliza-

tion and proper methods' of cleaning.

"5.

That were it not for carbonation the bacterial count apparently

would be enormously high."

Cereal beverages have been brought into prominence by the pro-

hibition laws. Sippel in American Food Journal says that cereal

beverages can be divided into three groups:

Group I.—This group comprises cereal beverages prepared from

fermented beers by means of de-alcoholizing devices.

Group II.—Cereal beverages prepared by the use of malt but

unfermentetL

Group III.—Cereal beverages prepared by the use of malt and

unfermented.

Carbonated beverages are made from many different fruit juices as

followB:

Fruit Juice

Quarts Juioe Quarts

Water Lbs.

Sugar

Grape juice 1 1

Elderberry juice 1 1 2

Blackberry juice 1 1 1

Raspberry juice 1 1J5 1.5

Currant juice 1 2.5 2

Blueberry juice 1 2 1.5

Gooseberry juice 1 5 1J5

Strawberry juice 1 5 1

Cranberry juice .' 1 3 2

Cherry juice .., 1 2 1

Plum juice 1 1.5 1

Pear juice 1 0 %

Mulberry juice 1 2 3

Peach juice

1 1 1

Apricot juice 1 1 1

Loganberry juice

Rhubarb juice 1 4 2

Apple juice 1 0 %

Tomato juice 1 0 1

Orange juice 1 0 1

Nora: The above juices should be pasteurised before carbonation.

334 INDUSTRIAL FERMENTATIONS

Pumell says further in the same article that by far the greater

number of de-alcoholizing processes on the market to-day employ a

vacuum. The beer is boiled under a vacuum at a temperature of from

90° F. to 120° F., and in this" way the loss of these aromatio substances

is reduced to a Tninimmn. De-alcoholized beers prepared in vacuo do

not possess the "cooked" tastes noticeable in some beverages de-

alcoholized by boiling at atmospheric pressure. The esters and oils

esoaping with the alcohol do not all volatilize at the same temperature.

Advantage has been taken of this fact in certain processes which

employ reflux condensers and fractionating devices to collect the

various oils and esters and when de-alcoholization is complete, these

are returned to the beverage.

REFERENCES ON BEVERAGES.

Allen, R. M., et al. Ky. Agr. Exp. Sta., Bui. 192, pp. 59-126.

Barnard, 3. E. Indiana State Bd. of Health, Bui. No. 12.

Barker, B. T. Jour. Inst. Brewing, 17, pp.

425441.

Barker, B. T., and Hillier, V. F. Jour. Agr. Sci., 6, I, pp. 67-86.

Barker and Grove. Jour. Soc. Chem. Ind., 35, pp. 191-162.

Bigelow, Gore and Howard. U. S. Dept. Agr., Bur. Chem., Bui. 94.

Fraiy, G. G. Brewer & Molster, 38, pp. 48-52.

Gore, H. C. U. S. D. A., Yearbook, 1914, pp. 227-244.

Gore, H. C. U. S. D. A., Bui. 241.

Gore, H. C. U. S. D. A., Yearbook, 1906, pp. 239-248.

Gore, H. C. U. S. D. A., Bur. of Chem., Bui. 118.

Gore, H. C, 1915. Jour. Aes'n. Off. Agr. Chemists, Vol. 1, No. 1, pp. 120-130.

Grove, O., 1914. Univ. Bristol, Ann. Rpt. Agr. & Hort. Research Sta, pp

32-33.

Haniawa, J. MyooJ Centr., 1, pp. 163-166.

Heinrich, F. Z. Spiritusend, 36, pp. 317-319.

Huasman G. C. U. S. D. A., Farmers' Bui. 644.

Kayser, E. 1917. Bui. Soo. Agr., pp. 321-323.

Kita, G. Orig. Com. 8th Intern. Cong. Appl. Chem., 14, pp. 99-106.

McGill, A. Lab. of the Inland. Rev. Dept., Ottawa, Canada

Muller, H., and Osterwaller, A. Bui. Agr. Intell, 8 pp 1235-37

Saillard, E., 1916. Mon. Sci., 6, pp. 25-29.

Sherwood, N. P., and Young, C. C. Jour. Ind. Eng. Chem., 5, pp. 577-678

Shin, Sawamura. Jour. Coll. Agr. Tokyo, 5, pp. 189-191

Sippel, G. B., 1918. Am. Food Jour., 13, pp. 303-307.

Takahaahi, T. and Yammata^ T. Jour. Coll. Agr., Tokyo, 5, pp. 163-161

Teuso, T., et al. Jour. Am. Chem. Soc, 39, pp. 2723-2726

U. S. D. A., Yearbook, 1914, p. 227.

Y0U

2FKJL

and Sherwood

Jour.

Ind. and Eng.

Chem.,

3, No. 7 pp.

Yukama, M. Jour. Agr., Univ. Tokyo, 1, pp. 357-368.