Allen Paul W. Industrial Fermentations
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DRINKING WATER 346
CununingB, H. S. Investigation of the pollution and' sanitary conditions of the
Potomac River. Bui. 104, Hyg. Lab.. Wash.
J. W. Water Purification (text).
M A A
(
Fennel. E. A., and Fisher, M. A. Adjustment of culture medium reactions. Jour.
of Inf, Dis., 26, 1919, 444.
Flinn, Weaton, and Bogert. Water Worka Handbooks (text).
Frost, W. H. Confirmation tests for B. coli in routine water examinations.
Am. Jour. Pub. Health, 6, 1916, 686-8.
Gillespie, L. J. The reaction of soil and measurements of hydrogen ion con-
centration. Jour. Wash. Acad. of Sciences, 6, 1916, 7.
Goodell, J. Waterworks for
^mnU
cities and towns (text).
Hill, H. W. Porous tops for petri dishes. Jour. Med. Research, 13, 1904, 93.
Hill, EL W. The mathematics of the bacterial count. Public Health Reports
and Papers, 83, 1907, 110.
Itano,
A. The relation of hydrogen ion concentration of media to the pro-
teolytio activity of Bacillus subtilis. Bulletin 167, 1916, Mass. Agric. Ex.
Station,
Jordan, E. 0. The bacterial examination of water. Trans. XV. International
Cong, on Hyg. A Demog., 2, 1916, 47-60.
Kendall, A. I., and Walker, A. W. The isolation of Bacillus dysenteri© from
stools. Jour. Med. Research, 23, 1910, 481.
Kinyoun, J. J, and Deiter, L. V. On the preparation of Endo'B medium. Amer.
Jour. Public Health. N. S., 2, 1912, 797.
Levine, M. The correlation of the Voges-Proskauer and methyl red reac-
tions in the colon-aerogenes group of bacteria. Jour. Inf. Dis., 18, 1916,
368-67.
Levine. The significance of the Voges-Proskauer reaction. Jour, of Bacteri-
ology, 1, 1916, 163-164.
Lubs,
fL,A., and Clark, W. M. On some new indicators of the colorimetric deter-
mination of hydrogen-ion concentration. Jour. Wash. Acad. of Sciences, 6,
1916 609.
McClendon, J. F. New hydrogen electrodes and rapid methods of determining
hydrogen ion concentrations. Amer. Jour, of Physiology, 38, 1916, ISO.
MoClendori, J. F. A direct reading potentiometer for measuring hydrogen ion
concentrations. Amer. Jdur. of Physiology, 38, 1916, 186.
McCrady, M. H. The numerical interpretation of fermentation-tube results.
Jour. Inf. Dis., 17 1916, 183.
Metcalf.
Colon-like bacteria on grain. Science N. 8., 1906, 439.
Noyes, H. A. Agar-agar for bacteriological use. Science, N. 8., 44, 1916, 797.
Obst, M. M. Bile compared with lactose broth for determining the presence
of B, ooli in water. Jour, of Baot., l
t
1916, 73-9.
Prescqtt, S. C. The occurrence of organisms of sanitary significance on grains.
Biological studies of pupils of W. T. Dedgwick.
Race, J. Bacterial counts in water examination. Am. Jour. Pub. Health, 6,
1916,
488-96.
Race, J. The significance of B. coli in water examination. Am. Jour. Pub.
Health, 26, 1914, 768-769.
Rogers, L. A., Clark, W. M., and Davis, B. J. The colon group of bacteria.
Jour, of Inf. Dk, 14, 1914, 411.
Rogers, L. A., Clark, W. M., and Evans, A. C. The characteristics of bacteria of
the colon type found in bovine feces. Jour, of Inf. Dis., 15, 1914, 99.
Rogers, L. A., Clark, W. M., and Evans, A. C. The characteristics of bacteria
of the colon type occurring on grains. Jour, of Inf. Dis,, 17, 1916,
137.
Rogere, Clark and Evans. Bacteria of the colon type occurring on grain.
Soienoe^ N. S, 41, 1916, 624.
Smith, E. G. B. ooli on grains. Science, N. S., 21, 710.
Smith, H. M. The seaweed industries of Japan. Bulletin of the Bureau of
Fisheries, 24, 1904, 135.
Sorensen, S. P. L. Enzymstudien. Biochem. Ztschr., 21, 1909, 131 and 201.
346 INDUSTRIAL FERMENTATIONS
Tanner E W Comparison of the number of water bacteria crowing on agar
at 37 degrees C. and on gelatin at 20 degrees C. Univ. of Hi. Bui. No. 13.
Water Survey Series No. 12, 1916, 242-8. . _
Whirrole Q C On the necessity of cultivating water bacteria in an atmosphere
saturated with moisture. Tech. Quart, 12, 1809, 276.
Whittaker, H. A. The source, manufacture and composition of commercial
Agar-agar. Jour. Amer. Pub. Health Aasoo., n.8., 1, 1911. 632.
U. S. Treasury Department. Bacteriological standard for drinking water.
Chapter
28.
The
Egg
Industry.
Interest
in the
bacteriology
of
eggs arose from
the
fact that
the
spoiling
of
eggs
was
found
to be due to
bacterial attack. Further,
some
of the
diseases
of
poultry
are
caused
by the
bacterial infection
of eggs
and are
disseminated
in
this
way.
Considerable literature
has
been published
on the
subject,
and
interest
is
still growing
due to the
rapid rise
of the
poultry industry.
Mauer (1911) examined
600
fresh eggs' bacteriologioally
and
found
that over
18%
contained bacterial infection.
In
1914, Bushnell
and
Mauer found that 23.7%
of
2,759 fresh eggs were infected with
bac-
teria. Rettger concluded from
a
study
of
about 4,000 fresh eggs that
normal fresh eggs
are
generally sterile. Only
9% of the
fresh eggs
which
he
examined contained bacteria.
It
has
been well demonstrated
by
Mauer (1911), Pernot (1908),
and
Cao
(1908), that bacteria
can
pass through
the
normal
egg
shell.
Mauer (1911) found that
out of 100
infected eggs
82% had
infected
yolks,
25.9%
had
infected whites,
and 7.9% had
both
the egg
white
and yolk infected.
In
1912, Stiles
and
Bates found 87%
of
613 yolks
and
70% of 616
whites
of
fresh eggs
to be
infected. Bushnel
and
Mauer (1914) arrived
at the
following results:
Per cent infected
in
yolk
at
20 degrees
C 19.3
((
tt tt it u no tt ec JO
" "white"
20 " "..'.'.'..'.'.'.['.'. 2J6
it
tt tt It tt OQ tt it no
In explanation
of the
fact that
egg
white
of
infected eggs usually
has less bacteria than
egg
yolk, Rettger
and
Sperry (1912) reported
that
egg
white
has an
antiseptic property. They
say
that this anti-
geptio effect
is
more active
at 37
degrees
C.
than
at 20
degrees
C.
The first method used
in the
bacteriological examination
of
eggs
was
a
direct microscopic method. Later
Cao
used
a
method
of en-
richment followed
by
planting
on
agar.
He
washed
the egg
carefully
in soap
and
water, then placed
it in
1:1,000
mercuric chloride solution
for
10
minutes followed
by
drying
in
alcohol
and
ether.
The egg was
then punctured
at
both ends with
a
sterile needle
so
that
the egg
white
could
be run out
into
80 cc. of
sterile broth
in a
flask. After
the
white
had
run out the
yolk
was
added
to 80 cc. of
sterile broth
in
another
flask. The
egg
broth mixtures were thoroughly shaken
and
incubated
for
24
hours
at 37
degrees
C. At the end of
incubation
the egg
broths
were plated
on
agar using several dilutions.
347
348 INDUSTRIAL FERMENTATIONS
Some of the results obtained by Hadley and Caldwell (1916) are as
follows:
"Of 2,520 fresh eggs examined by the direct method 8.7% showed
bacterial infection in the yolk. The percentage of infection obtained
for individual hens per year varied between 2.8 and 15, the average
being 9. No hen laid all sterile eggs during any full year. No correla-
tion was observed between percentage of infection and hatchability.
No correlation was observed between percentage of infection and
fecundity, age of the hens, or the Beason of the year. The percentage
of infection for infertile and for fertilized eggs was essentially the
same."
Hadley and Caldwell came to the conclusion that the most prob-
able source of primary egg infection is the ovaries of the fowl, which
become infected by bacteria escaping through the intestinal wall into
the portal circulation. They say that the nature of the bacterial
species occurring in the primary infeotion of eggs: makes clear the
fact that primary infection plays no r51e in bringing about the de-
composition of eggs, and that this decomposition is due to secondary
infection.
T. E. Rush gives a very satisfactory method of bacteriological
examination of eggs as follows: "A simple technique for the bac-
teriological examination of shell eggs. . . . The eggs' are first immersed
in a strong soap solution (the standard soap solution used in water
analysis has been found to be very satisfactory) and scrubbed with a
small brush to remove any adherent dirt and hen feces; then they
are thoroughly dried in a clean towel and immersed in a mer-
curic chloride solution (1:1,000) and allowed to remain about ftve
minutes.
"The egg is now removed from the mercuric ohloride solution,
care being taken to handle it by the small end, and without drying,
it is put into 60-70 per cent alcohol, where it is allowed to remain a
few minutes,
"Again handling the egg by -the small end it is placed upon a
three-inch clay triangle (which has been previously flamed to insure
sterility) large end down and the alcohol ignited by quickly passing
a flame under the egg. The success of the method from this point on
depends upon the formation of a drop of water from the alcohol
(60-70 per cent alcohol has been found most satisfactory) on the
bottom (large end) of the egg.
"When the alcohol has burned off, a very hot flame (Tirrell burner)
is directed at the drop of water on the under side of the egg and after
sufficient heating a piece of the egg shell from 1 to 2 cm. in diameter
snaps off. In some cases the vitelline membrane is broken at this
point and the contents of the egg run out, so it is necessary to have a
container ready for use.
"If the vitelline membrane does not break at this point or all the
contents do not run out, it is only necessary to apply the flame gently
to the top (small) end of the egg when the expansion of the air will
THE EGO INDUSTRY 349
totally empty the shell. Care must be taken at this point not to bum
the egg shell or ooagulate the oontents. This heating should be done
with a nearly luminous flame.
"The most satisfactory type of receiver is a large Phillips beaker,
which has been previously sterilized with a sufficient quantity of
broken glass in it to cover the bottom of the flask. This broken glass
serves to cut up both the yolk and white and make a homogeneous
mixture from which an average sample can be withdrawn and plated,
using the usual precautions."
Decay in Eggs.
Pennington, Jenkins and Betts, say: "Mold may penetrate a wet,
broken shell and attach itself to the inner surface in the form of
irregular patches. If the growth takes place at low temperatures,
the affected portions of the white are gelatinized. These mold spots
appear as dark areas before the candle, and are seen easily if not
covered with the fingers.
"The condition of the yolk is one of the most important factors
to be determined when judging the quality of eggs by candling. When
a fresh egg is twirled before the candle the yolk is dimly seen as a dark
and shadowy object moving slowly in the white. The more transparent
the shell the more distinctly is the yolk seen. The yolk sac is so strong
and the white so firm that the spherical form of the yolk is altered
very little when the contents of the egg are set in motion by the turn-
ing during candling.
"Because of the thinner condition of the white, the yolk of a stale
egg is seen much more plainly on candling than that of a fresh egg.
As the egg ages the yolk sac weakens, and since the white becomes
thinner at the same time the outline of the yolk is seen to ohange when
the egg is rotated.
"
When such an egg is opened the yolk flattens out
and often breaks. The differences in the strength of the yolk sac of
eggs of varying degrees of freshness are indicated clearly. If eggs
which have weak yolks before the candle show whole yolks when
opened, they are graded as good if no other cause for rejection is
observed.
"When the yolk of an egg is so weak that a shake in the hand
causes it to break and mix with the white, the egg should be graded
as unmarketable, for during shipment it is very likely to become unfit
for food. These eggs are difficult to grade accurately by candling.
They are of such inferior quality, however, that in case of doubt they
should be classed as inedible.
"The yolk sao may so weaken that the yolk seeps or strains through
into the white. In these eggs the yolk would appear whole before
the candle, but it would be weak, and the white would have a cloudy
yellow color. Out of the shell the yolk will be seen to be flattened and
sometimes mottled and the white to be streaked with yolk. Very
olose oandling is required to deteot these eggs, and since they are
350 INDUSTRIAL FERMENTATIONS
border-line eggs, in which further deterioration is very rapid, they
should not be graded as marketable.
"The more common form of disintegration of the yolk takes place
through the rupture in one or more places of the yolk sac and the
mingling of the white and yolk. This mixing is commonly known as
'addling.' All degrees of addling may be found, from the egg in which
the yolk is just beginning to mix with the white to the egg in which
no vestige of white is seen. The eggs representing the early stage of
mixing are called 'mixed rots,' and those representing the later stage,
'white rots.' Both are inedible.
"Mixed rots are characterized on oandling and out of the shell
by the irregular mixture of white and yolk. Often one portion of the
yolk shows more deterioration than another, a oondition shown by a
darkened area on candling and by whitish streaks out of the shell.
"The characteristics noted for mixed rots are even more marked
in the white rots. In these eggs the white assumes a general yellow
appearance on candling and out of the shell.
"The incrusting of "tie yolk is a characteristic form of deterioration
among eggs with soiled shells which have been held in cold storage.
Under certain conditions the bacteria enter the shell, liquefy the white,
making it watery, and produce a coating or crust on the yolk. Before
the candle the yolk appears to have dark, mottled areas. Such eggs
are unfit for food.
"The position of the yolk also must be taken into consideration
when grading eggs by candling. In a fresh egg the yolk is slightly above
the center in the large end of the egg. Although lighter than the white,
it does not float against the shell because the ohalaz© tend to hold it
in a central position in the egg. As the egg becomes stale with age,
and especially from exposure to heat, the white is
1
weakened, thereby
making it possible for the yolk to float near the shell. This condition
indicates staleness if the egg shows shrinkage.
"As ageing continues, the yolk may adhere slightly to the shell,
but a quick twist of the egg may set the yolk free without breaking it.
In such a case the egg is edible, but a very low grade. With further
ageing the yolk will stick to the shell so that it can not be separated
without breaking the yolk sac, in which case the egg is classed as bad.
When the yolk is thus broken, as may happen when the egg is turned
quickly, the appearance of the egg before the candle is the same as
tnat of the mixed rot. Again, the yolk may be adherent at one point
and broken at another. These eggs deteriorate quickly into mixed
or white rote.
"Dampness may be another factor causing the yolk to stick to the
shell. In this case molds penetrate the shells as far as the yolk, which
becomes very heavily attached to the shell."
The preparation of the frozen and dried eggs is an industry which
has sprung up in the Middle West. Pennington says; "The frozen-
egg industry, hardly 15 years old, is permanent, because it has de-
veloped as the direct result of an economic need. Many eggs, such as
THE EGO INDUSTRY 351
cracked, small, dirty, shrunken and slightly heated eggs, commercially
termed seconds, reach the first concentration center in a wholesome
condition, but if shipped in the shell to a distant consuming center
they would markedly decompose and be entirely unfit for food pur-
poses.
The new industry believed that cracked eggs and seconds could
be conserved by freezing out of the shell, and the baker thereby sup-
plied with wholesome eggs at a reasonable price during the whole
year.
"As
WBB
to be expected, the new industry had to face many prob-
lems.
The general public had its usual prejudice against any food
coming from cold storage. The industry was ignorant of the general
principles of bacterial cleanliness in the commercial preparation of a
perishable
foodstuff.
Unprincipled persons, thinking they could con-
ceal the inferiority of tow-grade eggs by freezing them en masse,
brought the industry into disrepute. Food officials were groping in
the dark in their efforts to protect the public against decomposed eggs.
These contending forces were fast making the investment of money
in the preparation of frozen and dried eggs a hazardous business
proposition."
In their bulletin on the preparation of frozen and dried eggs,
Pennington et al, say: "If good organization was important in the
candling room, it was even more so in the breaking room; here the
product (good eggs being furnished) gained or lost in quality, depend-
ing upon the mode of handling. Here, also, the cost of preparation
increased or decreased with the efficiency of the working force. First
in importance was the foreman, for upon him should rest the responsi-
bility of the work of the breaking force and the condition of the
ultimate product. He should be able to command the respect of
his subordinates, be conversant with the fundamental principles of
bacterial cleanliness and be familiar with the different types of eggs
occurring in breaking stook.
"Owing to the decided ohangeB made in equipment and methods,
the routine work in the breaking room in 1912 was quite different from
that of 1911. The duties of the foreman the second season included
the enforcement of the following: Clean manipulation of the egg
during breaking, the proper method of grading, the changing of ap-
paratus and the cleaning of hands after breaking a bad egg, the correct
speed for breaking, the thorough washing and sterilization of utensils,
and the maintenance of discipline in the breaking force.
"Since the presence of one infected egg would contribute myriads
of bacteria to the liquid product, the study of the grading of eggs
out of the shell became a very important part of the work. As has
been stated, the candling of eggs is a very efficient means of elimina-
ting bad eggs from breaking stock, but it is by no means accurate. It
is also generally understood by those familiar with eggs before the
candle and out of the shell that there are some types of objectionable
eggs,
such as musty or sour eggs, whioh can only be detected when
broken. The laboratory findings on composite samples of eggs graded
352 INDUSTRIAL FERMENTATIONS
to definite types and broken under clean commercial conditions showed
as given in Bulletin 51 of the U. S. Department of Agnoulture, the
following facts: . ... „ ,. , ,,
"The majority of the samples of white rots, eggs with yolk lightly
adherent to the shell, and all of the samples of sour eggs, black rots,
eggs with green albumens, eggef with yolk heavily adherent to the
shell, and all other eggs with bad odors, were infested with bacteria.
B.
coli were present in most of these eggs and constituted the pre-
dominating organism in sour eggs.
"The eggs with yolk lightly adherent to the shell were slightly
lower in quality than the regular breaking stock eggs, whereas" the
sour eggs, white rots, eggs with green whites, and eggs with yolk
heavily adherent to the shell snowed considerably more deterioration.
Eggs with bloody whites or eggs with blood rings, should not be used.
The cause of the musty egg, the odor of which increases on heating,
thereby creating disaster in the bakery, has not been determined.
"Eggs with shell and inner membranes broken are termed 'leakers'
by the trade. There are all gradations, from the egg which has lost
very little of its contents to the egg which has practically nothing
left in its shell but the yolk.
"During periods of the year when receipts are low and the number
of leakers' consequently few, they are commonly sold in the shell to
the near-by consumers and employees of the packing house. In the
season of heavy receipts, when there are more leakers than can be
used locally, they are either thrown with the rots or broken out and
frozen. The second method of disposal is the one concerned in this
investigation.
"Formerly if the leakers were to be conserved for food purposes
the candlers sorted these eggs' from receipts as they worked and
either broke them immediately into a container near by or placed
them in pans or pails to be opened in another room."
The following conclusions concerning the frozen and dried egg
industry and also the Glossary are from Pennington, et al., in U.S.D A.
But. 224.
"1.
Eggs commonly used for breaking stock by reputable firms
-
are
small and oversized eggs, dirty and cracked eggs, and shrunken eggs.
"2.
In order to check deterioration, the eggs should be held in
chilled surroundings before and during the process of candling, break-
ing, and mixing preparatory to freezing and drying.
"3.
All eggs, even during the spring months, Bhould be candled
previous to breaking.
"4.
In order to insure well-candled eggs going to the breaking room,
the system of oandling should be such that the work of the individual
candlers is checked.
"5.
In order to prevent waste, the eggs difficult to grade should
be set aside by the regular candlers to be recandled by an expert.
"6.
All eggs used in the preparation of frozen and dried eggs should
be graded out of the shell as well as by the candle, because certain
THE EGG INDUSTRY 353
heavily infected eggs, such as sour eggs and eggs with green whites,
can only be detected when broken.
"7.
In order to insure a good product, bacterial cleanliness and care-
ful grading must be obtained during the process of preparation.
"8.
The fingers of the breakers should be kept dry and clean.
"9.
In order to prevent waste and to insure good grading not more
than three eggs should be broken into a cup before emptying.
"10.
Good eggs should not be saved when a bad egg has been broken
in a cup with them.
"11.
White and yolk ar.e contaminated less by the meohanical than
the Bhell method of separation. Only clean eggs should be separated
by the latter process.
"12.
The percentage of 'rots' rejected on candling and the organisms
in the liquid egg saved increases as the season advances.
"13.
Canned eggs with the majority of samples having counts of
less than 5,000,000 bacteria per gram, and with 100,000 B. coli or less
can be prepared in the producing seotion from regular breaking stock,
provided strict cleanliness and careful grading have been observed.
The ammoniacal nitrogen will very seldom be over 0.0024 on the wet
basis or 0.0087 on the dry basis.
"14.
A second-grade frozen product prepared from eggs showing
incipient decomposition to the senses, such as 'beginning sours' and
eggs with green whites, are not only heavily infected but chemically
decomposed. These eggs are unfit for food purposes.
"16.
Only two grades of canned eggs should be prepared when
grading eggs out of the shell, namely, food eggs and tanners' eggs.
"16.
Leaking eggs handled on special trays between oandling and
breaking room and graded carefully are as fit for breaking as regular
breaking stock.
"17.
Tanners' egg contains markedly larger numbers of bacteria
and larger amounts of ammoniacal nitrogen than does food egg.
"18.
The control of the supply of the air to drying belts to prevent
saturation from the liquid egg is an important factor .in preventing
multiplication of bacteria in the product during the process of
desiccation.
"19.
The amount of ammoniacal nitrogen in desiccated egg is not
a reliable index to the quality of the raw material from which it is
prepared, because this substance is volatilized unevenly during the
process of desiccation.
"20.
The following eggs should be discarded during grading: Black,
white mixed and sour rots, eggs with green whites, eggs with stuck
yolks,
musty eggs, moldy eggs,''blood rings,' eggs containing diffuse
blood, and eggs abnormal in odor.
Glossary.
" 'Seconds' are small and oversized eggs, dirty eggs, and shrunken
eggs.
" 'Leakers' are eggs with shell and inner membrane broken.
354 INDUSTRIAL FERMENTATIONS
rt
A 'blood ring' is a fertile egg in which the embryo has developed
sufficiently to show blood.
"A soft egg is an egg the yolk of which appears whole before the
candle, but breaks when opened.
"A 'strong odor' egg is an egg which has an eggy odor.
"An 'off' egg is an egg which has a slightly abnormal odor.
"A 'beginning sour' is an egg showing the first signs of the odor
characteristic of sour eggs.
" 'Mixed egg' is a product prepared by adding yolks to whole egg.
" 'Drip' is the liquid egg, mostly white, which collects in the bottom
of the breaking tray while eggs are being broken.
" 'Second-grade egg' is a product prepared from 'drip' and incipient
forms of deteriorated eggs, such as 'beginning sours,' eggs with light-
green whites, etc.
'"Tanners' eggs' are
1
a product made from the rejects of the
candling and breaking rooms, minus eggs of bad odor. It is used as
the name implies, for tanning leather.
" 'Flaky egg' as opposed to 'wet lumps' is the more thoroughly dried
portion of egg coming from the drying belts.
"A 'churn' is a device for breaking yolks and for mixing yolk and
whole egg."
Method of Egg Preservation.
Of the methods of food preservation three are commercially applied
to the preservation of eggs, namely, preservation of eggs by cold
storage, preservation by antiseptics, and preservation by sealing.
The cold storage of eggs is widely practiced and is of great
economic importance in leveling the price of eggs throughout the year.
The condition of eggs in cold storage is determined by the amount of
bacterial contamination of egg shell and egg before going into storage.
The action of the low temperature of storage simply retards bacterial
action, which is another name for spoilage. The generation time of
normal egg spoilage organism at summer temperatures may be as
short as thirty minutes or lengthened by low temperature to a period
of several days.
The storage of eggs in antiseptic solutions, although practiced by
some, is not very successful according to experiments' carried on by
the U. S. Dept. of Agriculture. By this investigation it was found
that eggs stored in salt water were not edible because of salt pene-
tration. Also the following information was obtained:
Treatment
Percentage
Bad
Packed in solution of water glass 00%
Solution of salicylic acid and glycerine 80
Rubbed with Bait 70
Paoked in bran 70
Sterilised in boiling water 12-16 sec 50
Solution of alum 50
Paoked in peat dust 20
Packed in wood ashes 20
Bono acid and water glass 20