MURDOCK AND BROKAW: ORANGE CONCENTRATE STORAGE
vor stability at 40°
F. of both heated and un-
heated concentrates showed an increase in flavor
stability with increased concentration from low
to intermediate and high densities in 12 out of
22 cases; there was no difference in 8 cases; and
a slight reduction in stability was found in
cases.
The 150°
2
F. treatment did not increase
flavor stability consistently at any level of con
centration.
LITERATURE CITED
Association of Official Agricultural Chemists. 1960. Of
ficial methods of analysis. 9th ed. Washington, D. C.
Bissett, O. W., M. K. Veldhuis, and N. B. Rushing.
1953. Effect of heat treatment temperatures on the storage
life of Valencia orange concentrates. Food Technol. 7, 258.
Bissett, O. W., M. K. Veldhuis, R. B. Guyer, and W. M.
Miller. 1957. Stability of frozen concentrated orange juice
III. The effect of heat treatment in the production of highBrix frozen concentrate. Food Technol. 11, 96.
Boggs, Mildred M., and Helen L. Hansen. 1949. Analysis
of foods by sensory difference tests. Advances in Food Re
search 2, 219. Academic Press. New York.
Carroll, E. A., R. B. Guyer, O. W. Bissett, and M. K.
Veldhuis.
1957.
Stability of frozen concentrated orange
juice. V. The effect of heat treatment at intermediate stages
of concentration on juices prepared from Valencia oranges.
Food Technol. 11, 516.
Cotton, R. H., W. R. Roy, C. H. Brokaw, O. R. McDuff,
and A. L. Schroeder.
1947.
349
Storage studies on frozen citrus
concentrates. Proc. Florida State Hort. Soe. 60, 39.
DuBois, C. W., and D. I. Murdock. 1955. The effect of
concentration on quality of frozen orange juice with par
ticular reference to 58.5° and 42° Brix products. Chemical
and physiological aspects. Food Technol. 9, 60.
Huggart, R. L. 1952. Effect of concentration on clari
fication in concentrated citrus juices.
Proc. Florida State
Hort. Soc. 65, 237.
Keller, George J., Randall G. Rice, R. J. McColloch, and
E. A. Beavens.
1954.
Stabilization of frozen citrus con
centrates by heat treatment. Food Technol. 8, 195.
Kew, Theo. J., and M. K. Veldhuis. 1962. Stability of
frozen concentrated citrus juices following adverse storage.
Food Technol. 16, (10), 119.
Loeffler, H. J.
1941. Processing of orange juice.
Ind.
Eng. Chem. 33, 1308.
MacDonnell, L. R., E. F. Jansen, and H. Lineweaver. 1945.
The
properties
6, 389.
of
orange
pectinesterase.
Arch.
Bjochem.
McColloch, R. J., R. G. Rice, Bruno Gentili, and E. A.
Beavens. 1956. Cloud stability of frozen superconcentrated
citrus juices. Food Technol. 10, 633.
Rice, R. G., G. J. Keller, R. J. McColloch, and E. A.
Beavens.
1954.
Fruit concentrates.
Flavor-fortified highdensity frozen citrus concentrates.
J. Agr. Food Chem.
2, 196.
Rouse, A. H., C. D. Atkins, and E. L. Moore.
1960.
Effecto of pectinesterase on the stability of frozen concen
trated orange juice. Proc. Florida State Hort. Soc. 73, 271.
Senn, V. J., Mildred D. Murray, and R. T. O'Connor.
1955. A proposed standard for designation of "cloud" in
citrus juices. U. S. Department of Agriculture Publication
ARS-72-8.
Washington.
U. S. Department of Agriculture. 1955. Standards for
grades of frozen concentrated orange juice. Agric. Marketing
Service.
Dec. 1 (3rd issue).
Washington.
FURTHER OBSERVATIONS ON HOLDING 6-OZ. CANS OF
FROZEN CONCENTRATED ORANGE JUICE AT ROOM
TEMPERATURE AND 40 F
D. I. Murdock and Charles H. Brokaw
of abuse in terms of temperatures at 40° F., or
above.
Minute Maid Company
A Division of The Coca-Cola Company
Orlando
In the marketing of frozen citrus concentrates
there has been
chronic
occurrence
of customer
complaints
to
explosions.
Complaints
due
can
of this type, fortunately, have been exceedingly
low—averaging less than 1.5 per 10,000,000 units
of 6 and
12-ounce cans
orange juice
by
one
sold
of frozen
according to
manufacturer
(7).
The
a
concentrated
survey made
persistent
oc
currence of this type of complaint led to an in
Since the previous paper dealt only with
product representative of the 1961 midseason
pack, it was decided to investigate the effect of
exposing frozen concentrated orange juice to
adverse storage conditions with samples repre
sentative of the 1961 Valencia season, and both
midseason and Valencia portions of the 1961-62
pack. By so doing, it was thought the results
would be more meaningful since considerably
more product would be under test. It was also
decided to study more critically the microbial
population in orange concentrate at both 40 °F.
and room temperature.
vestigation to determine the degree of abuse at
Procedure
40° F., and room temperature required to produce
can swells and can explosions in frozen concentra
Samples for this study were collected and ex
ted orange juice. The preliminary results of this
amined in the same manner as described in our
study were presented at the 1961 Annual Meeting
previous
of the Florida State Horticultural Society. Data
indicate that in order for cans of frozen concen
twelve 6-ounce cans of frozen concentrated orange
trated orange juice to swell and/or explode, the
end
product must have received a considerable amount
investigation ranged from 60-72 hours.
publication
(11).
As
a brief
review,
juice were collected from the freeze tunnel at the
of
each
evaporator
run which during the
The cans
FLORIDA STATE HORTICULTURAL SOCIETY, 1962
350
TABLE I
SPOILAGE DEVELOPING AT ROOM TEMPERATURE
IN
6-OZ.
CANS
OF ORANGE CONCENTRATE
Product Representative of Two Citrus Seasons
Days Required
No.
No.
Cans
Tested
Season
Day8
All
Cans Flat
Days Required
For 1 or More
Cans to Burst
For 1 or More
Cans to Swell
No.
% Swelled
Days
No,
Days
% Burst
1961 Mido(l)
ISO
2
3
21
3
2
1961 Valencia
100
2
3
5
3
1
1962 Mid»
100
2
3
1
50
3
1962 Valencia
Tempo
(1)
Range:
20
62
16
4
70-74°F.
Data from initial investigation,
were coded and placed immediately at 0 to —10°
covered, and the weeks they were held in cold
F. Four to 8 hours after the plant was again in
storage prior to test are as follows:
operation following a clean-up a similar set of
No.Cans
deeks Samples Held
at 0 to -10°F.
Prior to Test
samples was obtained. All samples were collected
Season
from one plant and this sampling procedure was
1961 Va lencia
1/13
to
6/18
372
5
-
1«
adhered to during the 1961 Valencia pack as well
1962
Hi dseason
1/17
to
3/4
300
10
-
16
as during the entire 1961-62 citrus season.
1962
Vi lencia
M/12
to
5/23
210
S
-
11
The
Period Co verd
Collected
number of cans collected each season, the period
TABLE
SPOILAGE DEVELOPING AT 40°F.
II
IN 6-OZ,
CANS OF ORANGE CONCENTRATE
Product Representative of Two Citrus Seasons
No.
Season
No. Cans
Tested
Weeks
All
Cans Flat
No.
Wks.
%
Swelled
Noo
vJks.
%
Burst
ft
10
U
5
3
7
1
100
H
5
3
16
2
50
5
6
2
8
16
ISO
1961 Valencia
100
1962 Mido
(1)
Weeks Required
For 1 or More
Cans to Burst
5
1961 Mido(l)
1962 Valencia
Weeks Required
For 1 or More
Cans to Swell
Data from initial investigation.
MURDOCK AND BROKAW: ORANGE CONCENTRATE STORAGE
Three separate studies were made—one for each
sectional sample was also plated on the media
just described.
of the above seasons.
All product representative
of a given pack
50 to
100 cans
of
concentrate
placed
at
This phase of the experiment was
made over a 10-week period.
Just prior to plating, the 42°
was removed from cold storage at one time.
Sub-samples were then selected so that the
room
trate
samples
were
(single strength)
temperature (70-74°F.) contained product before
ported
and after each clean-up.
used
These were examined
on this
to
reconstituted
basis.
determine
Orange
the
total
serum
of these two temperatures.
erated from the malt agar plates.
examination
period.
terval
In
a
was
checked
addition,
10-can
daily
each
sample
day
entire pack was plated in
held
at
a
5-day
40° F.
was
corded separately.
It was also used as
Samples col
lected during the 1962 Valencia season were also
plated on McClesky's agar (5). This medium was
of
the
of gum-forming organisms.
because
of
its
specificity
for
the
The
count
recorded
was the
On
McClesky's
agar
only
the
gum-forming
MICR0BIAL-P0PULATI0N-IN-6-0Z.
CANS-OF-ORANGE-CONCENTRATE-STORED-AT-ROOM-TEMPERATURE.
P RODUCT-REPRESENTATIVE-OF
196I-AND-I962-VALENCIA-SEAS0NS.
-10,000,000
-1,000,000
TOTAL-VIABLE-ORGANISMS
YEASTS
_ 10,000
=-1,000
- CANS-FLAT-WHEN-PLATED.
i
■4*
%-OF-CANS-SWELLED-OR-BURST-WHEN-PLATED.-
J
z
DAYS-AT-ROOM-TEMP. (7O-74#-F.)
Figure 1.
average
of each set of duplicate plates.
weekly for swells, at which time a 10-can cross-
-100,000
growth
All plates were ex
amined after 72-96 hours of incubation at 30°C.
(86°F.).
examined
was
microbial
Yeast population was enum
used
(pH 3.5).
agar
point type colonies which were counted and re
in
duplicate on orange
Brix
a differential medium for gum-forming and pin
this
representative
serum and acidified malt agar
Concentrate
over
during
12°
viable
population of the product.
Product held at room temperature for visual
Brix concen
to
juice and all counts were re
A du
plicate group was placed at 40°F. to be similarly
examined. Another replicate set of samples was
set aside for microbiological examination at each
visually for swells and can explosions.
351
I
1
FLORIDA STATE HORTICULTURAL SOCIETY, 1962
352
colonies
were
counted.
Representative
gum-
dicating
the
presence
of
acetylmethylcarbinol
forming colonies were picked from each plate and
streaked on orange serum agar slants for future
and/or diacetyl.
All counts from each 10-can sampling period
reference. The catalase reaction of each gumforming colony was determined, according to a
were converted into logarithms, averaged, and
the antilogs recorded.
The concentrates used
for this study had an average of 41.9° Brix,
procedure described by Murdock et al. (10),
which consisted of flooding the plate with a 3%
solution of hydrogen peroxide.
If
effervescence
occurred the colony was considered "catalase posi
tive." If no reaction, the colony was considered
"catalase negative." The isolated cultures were
inoculated
into
juice (pH 3.8).
sterile, single strength orange
If growth occurred as evidenced
by a microscopic examination of the juice they
were considered potential "off-flavor" producing
organisms.
The Voges-Proskauer
(V.P.)
test
was made by growing the organisms in sterile
orange
juice,
then
adding
alphanaphthol
KOH creatine reagents to the culture.
and
A posi
tive reaction was characterized by an intense
pink color which developed in a few minutes, in
citric acid ranged from 2.28 to 3.20%, and Brix/
acid ratio from 13.0 to 18.4:1.
The pH ranged
from 3.7 to 3.8.
Results
Spoilage Developing at Room Temperature and
IfO°F.
Spoilage developing at room temperature in
samples
of 6-ounce cans of orange
representative
of
1960-61
and
seasons is presented in Table I.
results obtained when a similar set of samples
were stored at 40°P.
Data show concentrate re
moved from cold storage did not spoil when held
for 2 days at room temperature, at which time
STOREP-AT-ROOM-TEMPERATURE.
PRODUCT-REPRESENTATIVE-OF
I96I-AND-I962-VALENCIA-SEAS0NS.
C AT ALASE(-P ROAN ISMS
2
DAYS-AT-R00M-TEMP.(70-74°-F)
Figure 2.
citrus
Table II shows
GUM-FORMING-ORGANISMS-IN-e-OZ.-CANS-OF-ORANGE-CONCENTRATE.
I
concentrate
1961-62
3
MURDOCK AND BROKAW: ORANGE CONCENTRATE STORAGE
all cans remained "flat"
were not swelled).
burst,
3
40° F.,
all
or
more
cans
after 4 weeks.
(that is, the can ends
For product to swell and/or
days
of
were
concentrate
required.
were
At
still
flat
353
A graphical presentation of the results is pre
sented
in
Figure
1.
The
data
show
that
the
total viable population consisted mostly of yeast
after the 4th and 5th day.
This was also re
Five or more weeks were required
ported in our previous paper when an examina
for cans to swell. Additional results are shown in
tion of orange serum agar plates showed a ma
Tables I and II.
jority of the colonies present to be yeast
It is interesting to note that results obtained
during this study reconfirm our findings obtained
during the midseason portion of the 1961 pack.
These data have been incorporated in Tables I
and II to show this comparison.
Microbiological Results at Room Temperature
An examination of the data showed the microbial population in 6-ounce cans of orange con
centrate stored at room temperature, represen
tative
of
the
closely with
1961
Valencia
results
Valencia pack.
obtained
season,
during
compared
the
1962
Therefore, for sake of brevity,
data from these two seasons have been combined.
These
organisms
grew
rapidly
in the
after the first day of the test period.
The pinpoint colonies, which are characteris
(9),
and the gum-formers showed a reduction in
viable numbers during the first 3 days followed
by a slight increase in population at the end of
tic of the colonies produced by lactobacilli
the 5-day test period.
Figure 2 is a plot of the gum-forming or
ganisms shown in Figure 1, separated in accord
ance
with
their
catalase
reaction.
It
up principally of catalase positive organisms.
Ml CROBIAL-POPULATION-1N-60Z.
PRODUCT-REPRESENTATIVE-OF
I96I-VALENCIA-SEAS0N
10
i
I
I
WEEKS-AT-40°-F.
Figure 3.
10
10
l<l|
%-OF-CANS-SWOLLEN-WHEN-PLATED
I
will
be
noted that the gum-forming population is made
CANS-OF-ORANGE-CONCENTRATE-STORED-AT- 40°-F
-CANS-FLAT-WHEN-PLAT ED.-
(11).
product
I
I
I
In
FLORIDA STATE HORTICULTURAL SOCIETY, 1962
354
fact,
99%
of
the
gum-formers present
at
the
start of the test period gave a positive reaction
when tested with hydrogen peroxide.
dicating they do not product diacetyl or acetylmethylcarbinol.
It should
It is suggested the large yeast population in
be pointed out that it is the catalase negative
the product between the 4th and 5th days of the
organisms which produce diacetyl in orange juice
test period is responsible for the slight increase
and concentrate, the flavor of which has been
in organisms producing pinpoint and gum-form
described as being similar to "buttermilk" (3, 4,
ing colonies.
8).
uble (sugar) solids in the concentrate as a source
It is this group
of organisms along with
Yeast, in growing, utilize the sol
those belonging to the genus Lactobacillus which
of energy.
are of sanitary significance in the production of
the original 42°
frozen
where the lactic acid organisms may grow.
concentrated
orange
juice
(13).
Cata
As the sugar solids are reduced from
Brix level, a point is reached
Pre
been implicated in the production of off-flavors
vious studies have shown that organisms belong
ing to the genera Leuconostoc and Lactobacillus
in orange juice or concentrate.
grow very slowly or not at all at 42° Brix (12,
lase positive gum-forming organisms have never
However, a study
of 38 catalase-positive cultures isolated through
1).
out this investigation showed that 36 organisms
grew in orange juice with the production of a
Brix range of 25-38° Brix or lower, with prob
able production of diacetyl (6).
variety of non-specific off-flavors, most of which
Microbial Population in Product at 40°F.
were
characterized
as
bitter
or
tart.
All
or
ganisms were V.P. negative in orange juice in
However, there is certainty of growth in the
Microbial population in 6-ounce cans of orange
concentrate stored at 40°F. representative of the
6UM-F0RMING-0RGANISMS-6-0Z:CANS
0F-0RANGE-C0NCENTRATE-ST0RED-AT-40°-F.
PRODUCT-REPRESENTATIVE-OF
I96I-VALENCIA-SEAS0N.
CATALASEt-HORGANISMS.
- V
\
CATALASEHORGANISMS
4
S
WEEKS-AT-40°-F.
Figure 4.
MURDOCK AND BROKAW: ORANGE CONCENTRATE STORAGE
1961 Valencia season is presented in Figure 3.
Data show all organisms died in 42° Brix con
centrate held at 40°F. during the first 6 weeks
of the test period, after which there was an in
crease in yeast population. The gum-formers and
organisms producing pinpoint type colonies, on
the other hand, continued to show a reduction
in Figures 3 and 4. The yeasts, however, showed
a noticeable increase in numbers after 6 weeks
in product representative of the 1962 midseason
pack. Similar data were also obtained during the
midseason portion of the 1961 pack which were
presented in our previous paper (11).
In our original publication it was reported
that a greater percentage of swells occurred at
in numbers.
is
355
Another graph of the gum-forming organisms
both
shown
collected after, rather than before, each clean-up
in Figure
4,
where those
organisms
room
samples
(11).
were
catalase
positive
and
12%
rather
than
before,
each
clean-up.
A
graph
stored at 40°F. representative of the 1961 Va
viable gum-forming organisms occurred through
lencia season is presented in Figure 5.
out the test period.
logical
the microbial
population
swells
in
the
1961
that
pack
the
is
from
was
As indicated in Figure 3, a steady decrease in
assume
made
it
showing
to
relationship
data
catalase negative at the start of the test period.
Except for yeasts,
this
present
in
noted there was a greater yeast population after,
88%
our
40°F.
reaction have been plotted.
present,
examining
and
giving a catalase positive and catalase negative
Of the gum-formers
In
temperature
samples
It seems
occurrence
directly
of
related
can
to
in all 6-ounce cans of orange concentrate stored
levels of yeast population as shown in the present
at 40°F. gave results similar to those presented
studies.
YEAST-P0PULATI0N-IN-60Z.-CANS-0F-0RANGEC0NCENTRATE-AT-40°-F.
REPRESENTING-PRODUCT-BEFORE-ANDAFTER-CLEAN-UP-FROM-igSI-VALENCIA-SEASON.
—
10,000
— 1,000
WEEKS-AT-40°-F.
Figure 5.
FLORIDA STATE HORTICULTURAL SOCIETY, 1962
356
As stated in our previous paper, it seems unlikely
Diacetyl Analyses
Product representative of the 1961 portion of
the customer would hold product in a refrigerator
the Valencia pack stored at 40°F., and concen
for
trate
swells or explosions, when reported by the cus
room
from
the
1962
temperature
Valencia
(70-74 °F.)
season
were
held
at
checked
throughout the test period for diacetyl in accord
ance with the procedure described by Byer
such
an
extended
period.
Therefore,
can
tomer, must be the result of holding concentrate
at temperatures above 40°F.
(2).
Summary
Results which are presented in Figure 6 show
Six-ounce cans of frozen concentrated orange
no increase in diacetyl in product stored at 40°F.,
while at room temperature a noticeable increase
juice were collected, before and after each clean
occurred between
up, from one plant during the Valencia portion
the
3rd
and
5th
days.
It is
believed this is due to the activity of lactic acid
of the 1960-61 citrus season and again through
organisms which was mentioned previously.
out the following season.
Representative samples
Based on data representative of the 1960-61
from each lot were held at both room temperature
and 1961-62 citrus seasons, it is evident that in
order for cans of frozen concentrated orange
visually for swells and can explosions. They were
(70-74°F.)
and 40°F.
Samples were examined
juice to swell and/or explode they must be held
for 4 or more weeks at 40°F., 3 or more days at
also checked for total viable organisms, yeasts,
room temperature, or intermediate temperatures.
intervals
gum-formers,
the
test
at periodic
period.
At room temperature all cans of concentrate
When product is subjected to these adverse con
ditions it is the yeasts, rather than lactic acid
organisms, which are responsible for spoilage.
and pinpoint colonies
throughout
remained flat and showed no evidence of spoilage
2
days
after
removal
from
cold
storage.
DIACETYL-ANALYSES-0N-0RANGE-C0NCENTRATE-PACKED-IN-602.-CANS-ST0RED
AT-R00M-TEMP,-AND-40o-F-REPRESENTATlVE-0F-l961-AND-l962-VALENCIA-SEAS0NS.
EACH-ANALYSIS-MADE-FROM-A-IO-CAN'COMPOSITE-S AMPLE.
r"
1962-VALENCIA-PRODUCT-HELD-AT-ROOM-TEMP.
-6.2,
I96I-VALENCIA-CONCENTRATE-$TOREO-AT-40P-F.
—O.00
4
5
WEEKS-AT-40°-F.
2
3
T-R0 0M-TENIP.-(70-74°-F.).
Figure 6.
For
MURDOCK AND BROKAW: ORANGE CONCENTRATE STORAGE
product to swell and/or burst, 3 or more days
were required.
Five or more weeks were
required for spoilage to occur.
Yeasts were the only organisms which grew
rapidly in product stored at room temperature.
Bacteria
producing
pinpoint
and
gum
colonies
died off rapidly in concentrate during the first 3
days of the storage period.
Between the 4th and
5th day there appeared to be a slight increase
in the
population
of these
organisms.
During
this period there was also a noticeable increase
in the concentration of diacetyl in the product.
Except for yeasts, no microbial growth
curred
in
at 40°F.
42°
Brix
orange
concentrate
oc
stored
All micron1 ora showed a reduction in
numbers the first 6 weeks of the test period, after
which there was a noticeable increase in yeast
population.
gum
Organisms
colonies
continued
10-week storage period.
producing
to
die
pinpoint
and
throughout
the
The absence of growth
of these organisms was reflected in the concen
tration of diacetyl in the product which remained,
more or less, constant.
Gum-formers found in frozen orange concen
trate
were
predominantly
catalase
positive,
a
group of bacteria which do not pro duce diacetyl
or acetylmethylcarbinol in orange juice or con
centrate.
Acknowledgment
At 40°F. no swells developed at
the end of 4 weeks.
357
The authors gratefully acknowledge Messrs.
T. H. Shang and A. J. Mercer who assisted so
capably in performing the analyses.
LITERATURE CITED
1.
Berry, J. M., Witter, L. D., and Folinazzo, J. F.
Growth characteristics of spoilage organisms in orange juice
and concentrate.
Food Technol., 10, 553 (1956).
2.
Byer, Ellis, M.
Visual detection of either diacetyl
or acetylmethylcarbinol in frozen concentrated orange juice.
Food Technol., 8,
173
(1954).
3.
Hays, G. L.
The isolation, cultivation, and identi
fication of organisms which have caused spoilage in frozen
concentrated orange juice.
Proc. Fla. State Hort. Soc,
135
(1951).
4.
Hays, G. L., and Reister, D. W.
The control of
"off-odor" spoilage in frozen concentrated orange juice. Food
Technol., 7, 383 (1952).
5.
McClesky, C. S., Faville, L. W., and Barnett, Rex
O.
Characteristics of leuconostoc mesenteroides from cane
juice. Journ. of Bact., 54, 697 (1947).
6.
Minute Maid Company Laboratory data (unpublished).
7.
Minutes Maid Company Survey of distribution and
handling of frozen citrus concentrates, (unpublished) (1961).
8.
Murdock, D. I., Troy, V. S., and Folinazzo, J. F.
Development of off-flavor in 20° Brix orange concentrate
inoculated with certain strains of lactobacilli and leucono
stoc. Food Technol., 6, 127 (1952).
9.
Murdock, D. I., Folinazzo, J. F., Troy, V. S. Evalua
tion of plating media for citrus concentrates. Food Technol.,
6, 181 (1952).
10.
Murdock, D. I., Folinazzo, J. F., and Brokaw, C. H.
Some observations of gum-forming organisms found on fruit
surfaces.
Proc. Fla. State Hort. Soc, 278 (1953).
11.
Murdock, D. I., and Brokaw, C. H. Some observa
tions on holding 6-oz. cans of frozen concentrated orange
juice at room temperature and 40 °F.—A preliminary report.
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