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The Effect of Storage Time and Holding Temperature on Egg Interior Quality in Uganda
The Effect of Storage Time and Holding Temperature on Egg Interior Quality in Uganda J. C. M . T R A I L Livestock Experimental Station, Entebbe, Uganda (Received for publication August 13, 1962)
T
perature and five groups at 50°F. to 55°F., the storage times being 2, 7, 14, 21 and 28 days. The mean maximum room temperature was 79°F. and the mean minimum 65°F., with a 24 hour mean temperature of 71°F. Prior to the first egg collection, and after the 14th collection, three consecutive eggs for each hen were broken out within 30 minutes of being laid and the average Haugh unit value for each hen determined from these six readings. In all determinations of egg interior quality, egg weight was measured to the nearest gram immediately prior to breaking and each egg then cracked and opened on to a flat glass plate mounted on a stand. The height of the thick albumen was then measured to the nearest 0.1 mm., using a micrometer mounted on a tripod and Haugh unit values computed. The Haugh unit value for each egg in each treatment was then subtracted from t h a t hen's average Haugh unit value to give the change in interior quality. The changes in Haugh units were analysed statistically by employing analysis of variance and testing for significant mean differences between treatments by using Duncan's "new multiple range test" (Duncan, 1955).
METHODS AND MATERIALS
Eggs used in this experiment were obtained from 63 Rhode Island Red pullets, 10 months of age, maintained in individual cages a t the Livestock Experimental Station, Entebbe. F o r t y eggs were collected daily for 14 days, except on the first day when only 30 were available and each egg placed at random in one of ten groups, within 30 minutes of being laid. Five groups were stored at normal room tem-
RESULTS
The mean Haugh unit value of the 378 newly laid eggs examined from the 63 hens used was 92.17. The effects on egg interior quality of storage for 2, 7, 14, 21 and 28 days a t the normal temperature of 71°F. and the re-
310
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H I S study was undertaken to determine the relative effect of storage time and temperature on egg quality in Uganda, in order that recommendations could be made whereby eggs of the highest quality might be marketed. Deterioration in the interior quality of an egg begins immediately it is laid and is dependent on several factors, two of the most important being time and temperature. (Fry and Newell, 1957). The Haugh unit (Haugh, 1937) was recommended by Brant et al. (1951) as the simplest and most applicable quantitative measurement of egg interior quality and Wesley and Stadelman (1959) found that Haugh unit values were more significantly correlated to more quality measurements than any other of 13 methods of measuring the interior quality of eggs, examined. Nordskog and Cotterill (1953), in studies of repeatability estimates of albumen quality, determined t h a t observations based on three eggs per hen would give 93 percent of the maximum information which could be obtained if all the eggs from an individual hen were measured.
311
EGG INTERIOR QUALITY
55° R
7
14 DAYS
21
28
STORAGE
FIG. 1. Changes in Haugh units at different storage times and temperatures. TABLE 1.—Analysis of variance of changes in Haugh unit values Source of variation
D.f.
Mean square
Between treatments Within treatments Total
126 410 536
775.8126* 32.7756
* Significant at the . 0 1 % level.
frigerated temperature of 50°F. to 55°F. are illustrated in Figure 1. The analysis of variance of changes in Haugh unit values is given in Table 1. In
drawing up this table, analyses were done for each day separately, then the degrees of freedom and sums of squares totalled up for the 14 days. The analysis shows highly significant differences in changes in Haugh unit values between storage treatments. The mean change in Haugh unit value for each storage treatment is shown in Table 2, which also lays out the multiple range test for Haugh unit changes. From Table 2, it is seen that eggs stored in the refrigerated conditions for all periods up
TABLE 2.—Multiple range test for changes'- in Haugh unit values o,. storage
2 days 55<,F_
7 days 55oF^
Decrease in Haugh units
4.29
11.22
a
2 days 71op^
15.42
14 days 21 days 28 days SS o F _ 55oR
55oF_
15.87
17.65
22.20
7 days 71oR
29.09
14 days 21 days 28 days 71oF> 71oR
71oR
35.45
40.27
47.80
All changes from original quality are minus so minus signs omitted. Any two storage treatments not underscored by the same line are significantly different at the 1% level. Any two storage treatments underscored by the same line are not significantly different.
Downloaded from http://ps.oxfordjournals.org/ by guest on April 9, 2015
2
312
J. C. M.
to and including 28 days, were of significantly higher interior quality than eggs stored under normal temperatures for seven or more days. Eggs stored a t 71°F. for two days were significantly poorer in interior quality than eggs stored at 50°F. to 55°F. for 2 and 7 days; better, but not significantly better than eggs stored at 50°F. to 55°F. for 14 and 21 days; and significantly better than eggs stored at 50°F. to 55°F. for 28 days.
DISCUSSION These results show clearly t h a t as large scale egg production increases in Uganda, refrigerated egg holding rooms will have to be considered as an essential item of equipment if high quality eggs are to be marketed. As large markets are few, distances from producer to market can be very great and with high transport costs and secondary road systems below the standards of more advanced countries, frequent marketing is not easily possible. If once weekly marketing is considered the most frequent t h a t can be undertaken b y many farmers under present conditions
in Uganda, Table 2 shows t h a t seven day old eggs stored at normal temperatures are significantly lower in interior quality than eggs stored at 50°F. to 55°F. for 28 days and grade out, as illustrated by Table 3, with only 7 % in AA and 6 2 % in A, it becomes clear t h a t storage of eggs at lower temperatures is essential on the farm prior to distribution if high quality eggs are to be marketed. From Tables 1 and 3 it appears that weekly marketing of eggs stored at 50°F. to 55°F. would be the most feasible method of making good quality eggs available. These eggs, although only requiring marketing once per week, would be of significantly higher quality than eggs marketed every second day and stored at normal temperatures. One week old eggs stored at 50°F. to 55°F. graded 9 8 % in AA and A, with 6 9 % in AA, compared with one week old eggs stored at normal temperatures which graded 6 9 % in AA and A, with only 7 % in AA. In up-country areas where egg production may not be on a large enough scale to allow even once weekly transport of eggs to distant markets, it is of value to note t h a t eggs stored a t 50°F. to 55°F. for 14 days were of identical interior quality to eggs stored at normal temperatures for 2 days and even eggs stored for 21 days a t 50°F. to 55°F. were not significantly lower TABLE 3.—Ejfect of storage time and temperature on grade distribution Storage
%AA
%A
%B
%c
Original quality 2 days 71°F. 2 days 55°F. 7 days 71°F. 7 days 55°F. 14 days 71°F. 14 days SS°F. 21 days 71°F. 21 days 55°F. 28 days 7l°F. 28 days 55°F.
98.1 29.1 96.4 7.3 69.1 0 36.4 0 30.9 0 14.6
1.9 69.1 3.6 61.8 29.1 SO.9 61.8 27.2 69.1 5.5 78.1
0 1.8 0 30.9 1.8 49.1 1.8 72.8 0 92.7 7.3
0 0 0 0 0 0 0 0 0 1.8 0
Downloaded from http://ps.oxfordjournals.org/ by guest on April 9, 2015
The eggs were separated into grades according to Haugh unit values, these being AA, 79 and above; A, 56-78; B, 32-55; and C, 31 and below, and the results are laid out in Table 3. The percent of AA and A grade eggs, when stored at 71°F., dropped from 9 8 . 1 % and 1.9% respectively when new laid, to 2 9 . 1 % and 6 9 . 1 % after 2 days; 7.3% and 61.8% after 7 days; 0 % a n d . 50.9% after 14 days; 0 % and 27.2% after 21 days; and 0 % and 5.5% after 28 days. Similarly the percent of AA and A grade eggs stored at 50°F. to 55°F. dropped from 9 8 . 1 % and 1.9% to 96.4% and 3.6% after 2 days; 6 9 . 1 % and 2 9 . 1 % after 7 days; 36.4% and 61.8% after 14 days; 30.9% and 6 9 . 1 % after 21 days; and 14.6% and 7 8 . 1 % after 28 days.
TRAIL
313
EGG INTERIOR QUALITY
in quality than the 2 day old eggs stored at normal temperatures, while all three conditions and periods of storage gave between 98% and 100% of eggs in grades AA and A.
at 55°F. were not significantly lower in interior quality than, and graded out as well as, two day old eggs stored at the normal temperature of 71°F. ACKNOWLEDGMENT
SUMMARY
The author wishes to thank the Director of Veterinary Services and Animal Industry for permission to publish this paper. REFERENCES Brant, A. W., A. W. Otte and K. H. Norris, 1951. Recommended standards for scoring and measuring open egg quality. Food Tech. 5: 356-361. Duncan, D. B., 1955. Multiple range and multiple F Tests. Biometrics, 11: 1-42. Fry, J. L., and G. W. Newell, 1957. Management and holding conditions as they affect the interior quality of eggs. Poultry Sci. 36: 240-246. Haugh, R. R., 1937. The Haugh unit for measuring egg quality. U. S. Egg Poultry Mag. 43: 552555, 572-573. Nordskog, A. W., and 0. Cotterill, 1953. Breeding for egg quality. 2. Sampling hens for interior quality. Poultry Sci. 32: 1052-1054. Wesley, R. L., and W. J. Stadelman, 1959. Measurements of interior egg quality. Poultry Sci. 38: 474-481.
A Biological Assay for Metabolizable Energy in Poultry Feed Ingredients Together With Findings Which Demonstrate Some of the Problems Associated With the Evaluation of Fats I . R . SlBBALD AND S. J . SLINGER Departments of Nutrition and Poultry Science, Ontario Agricultural College, Guelpk, Ontario, Canada (Received for publication August 17, 1962)
I
N 1958 a programme was initiated at this institution, the objective of which was to obtain metabolizable energy (M.E.) values for representative samples of all feedingstuffs of practical importance to the Canadian poultry industry. Prelim-
inary studies were designed to test two basic assumptions: 1) that the M.E. value of an ingredient is independent of the other diet components, and 2) that the value remains relatively constant irrespective of the age of type of bird to which
Downloaded from http://ps.oxfordjournals.org/ by guest on April 9, 2015
The relative effect of storage time and refrigerated and normal temperature holding on egg interior quality in Uganda was studied. Haugh units were used to measure the broken out quality of eggs stored at 71°F. and 50°F. to 55°F. for 2, 7, 14, 21 and 28 day periods. Eggs stored at 50°F. to 55°F. for all periods up to and including 28 days had significantly better interior quality than eggs stored at 71°F. for 7 or more days. The eggs were graded and the most suitable systems of holding and marketing suggested, to allow the highest quality eggs to be made available. Once weekly marketing of eggs stored at 55°F. was recommended as the most practical method of getting highest quality eggs into circulation, although it was noted that 14 and 21 day old eggs stored
T
perature and five groups at 50°F. to 55°F., the storage times being 2, 7, 14, 21 and 28 days. The mean maximum room temperature was 79°F. and the mean minimum 65°F., with a 24 hour mean temperature of 71°F. Prior to the first egg collection, and after the 14th collection, three consecutive eggs for each hen were broken out within 30 minutes of being laid and the average Haugh unit value for each hen determined from these six readings. In all determinations of egg interior quality, egg weight was measured to the nearest gram immediately prior to breaking and each egg then cracked and opened on to a flat glass plate mounted on a stand. The height of the thick albumen was then measured to the nearest 0.1 mm., using a micrometer mounted on a tripod and Haugh unit values computed. The Haugh unit value for each egg in each treatment was then subtracted from t h a t hen's average Haugh unit value to give the change in interior quality. The changes in Haugh units were analysed statistically by employing analysis of variance and testing for significant mean differences between treatments by using Duncan's "new multiple range test" (Duncan, 1955).
METHODS AND MATERIALS
Eggs used in this experiment were obtained from 63 Rhode Island Red pullets, 10 months of age, maintained in individual cages a t the Livestock Experimental Station, Entebbe. F o r t y eggs were collected daily for 14 days, except on the first day when only 30 were available and each egg placed at random in one of ten groups, within 30 minutes of being laid. Five groups were stored at normal room tem-
RESULTS
The mean Haugh unit value of the 378 newly laid eggs examined from the 63 hens used was 92.17. The effects on egg interior quality of storage for 2, 7, 14, 21 and 28 days a t the normal temperature of 71°F. and the re-
310
Downloaded from http://ps.oxfordjournals.org/ by guest on April 9, 2015
H I S study was undertaken to determine the relative effect of storage time and temperature on egg quality in Uganda, in order that recommendations could be made whereby eggs of the highest quality might be marketed. Deterioration in the interior quality of an egg begins immediately it is laid and is dependent on several factors, two of the most important being time and temperature. (Fry and Newell, 1957). The Haugh unit (Haugh, 1937) was recommended by Brant et al. (1951) as the simplest and most applicable quantitative measurement of egg interior quality and Wesley and Stadelman (1959) found that Haugh unit values were more significantly correlated to more quality measurements than any other of 13 methods of measuring the interior quality of eggs, examined. Nordskog and Cotterill (1953), in studies of repeatability estimates of albumen quality, determined t h a t observations based on three eggs per hen would give 93 percent of the maximum information which could be obtained if all the eggs from an individual hen were measured.
311
EGG INTERIOR QUALITY
55° R
7
14 DAYS
21
28
STORAGE
FIG. 1. Changes in Haugh units at different storage times and temperatures. TABLE 1.—Analysis of variance of changes in Haugh unit values Source of variation
D.f.
Mean square
Between treatments Within treatments Total
126 410 536
775.8126* 32.7756
* Significant at the . 0 1 % level.
frigerated temperature of 50°F. to 55°F. are illustrated in Figure 1. The analysis of variance of changes in Haugh unit values is given in Table 1. In
drawing up this table, analyses were done for each day separately, then the degrees of freedom and sums of squares totalled up for the 14 days. The analysis shows highly significant differences in changes in Haugh unit values between storage treatments. The mean change in Haugh unit value for each storage treatment is shown in Table 2, which also lays out the multiple range test for Haugh unit changes. From Table 2, it is seen that eggs stored in the refrigerated conditions for all periods up
TABLE 2.—Multiple range test for changes'- in Haugh unit values o,. storage
2 days 55<,F_
7 days 55oF^
Decrease in Haugh units
4.29
11.22
a
2 days 71op^
15.42
14 days 21 days 28 days SS o F _ 55oR
55oF_
15.87
17.65
22.20
7 days 71oR
29.09
14 days 21 days 28 days 71oF> 71oR
71oR
35.45
40.27
47.80
All changes from original quality are minus so minus signs omitted. Any two storage treatments not underscored by the same line are significantly different at the 1% level. Any two storage treatments underscored by the same line are not significantly different.
Downloaded from http://ps.oxfordjournals.org/ by guest on April 9, 2015
2
312
J. C. M.
to and including 28 days, were of significantly higher interior quality than eggs stored under normal temperatures for seven or more days. Eggs stored a t 71°F. for two days were significantly poorer in interior quality than eggs stored at 50°F. to 55°F. for 2 and 7 days; better, but not significantly better than eggs stored at 50°F. to 55°F. for 14 and 21 days; and significantly better than eggs stored at 50°F. to 55°F. for 28 days.
DISCUSSION These results show clearly t h a t as large scale egg production increases in Uganda, refrigerated egg holding rooms will have to be considered as an essential item of equipment if high quality eggs are to be marketed. As large markets are few, distances from producer to market can be very great and with high transport costs and secondary road systems below the standards of more advanced countries, frequent marketing is not easily possible. If once weekly marketing is considered the most frequent t h a t can be undertaken b y many farmers under present conditions
in Uganda, Table 2 shows t h a t seven day old eggs stored at normal temperatures are significantly lower in interior quality than eggs stored at 50°F. to 55°F. for 28 days and grade out, as illustrated by Table 3, with only 7 % in AA and 6 2 % in A, it becomes clear t h a t storage of eggs at lower temperatures is essential on the farm prior to distribution if high quality eggs are to be marketed. From Tables 1 and 3 it appears that weekly marketing of eggs stored at 50°F. to 55°F. would be the most feasible method of making good quality eggs available. These eggs, although only requiring marketing once per week, would be of significantly higher quality than eggs marketed every second day and stored at normal temperatures. One week old eggs stored at 50°F. to 55°F. graded 9 8 % in AA and A, with 6 9 % in AA, compared with one week old eggs stored at normal temperatures which graded 6 9 % in AA and A, with only 7 % in AA. In up-country areas where egg production may not be on a large enough scale to allow even once weekly transport of eggs to distant markets, it is of value to note t h a t eggs stored a t 50°F. to 55°F. for 14 days were of identical interior quality to eggs stored at normal temperatures for 2 days and even eggs stored for 21 days a t 50°F. to 55°F. were not significantly lower TABLE 3.—Ejfect of storage time and temperature on grade distribution Storage
%AA
%A
%B
%c
Original quality 2 days 71°F. 2 days 55°F. 7 days 71°F. 7 days 55°F. 14 days 71°F. 14 days SS°F. 21 days 71°F. 21 days 55°F. 28 days 7l°F. 28 days 55°F.
98.1 29.1 96.4 7.3 69.1 0 36.4 0 30.9 0 14.6
1.9 69.1 3.6 61.8 29.1 SO.9 61.8 27.2 69.1 5.5 78.1
0 1.8 0 30.9 1.8 49.1 1.8 72.8 0 92.7 7.3
0 0 0 0 0 0 0 0 0 1.8 0
Downloaded from http://ps.oxfordjournals.org/ by guest on April 9, 2015
The eggs were separated into grades according to Haugh unit values, these being AA, 79 and above; A, 56-78; B, 32-55; and C, 31 and below, and the results are laid out in Table 3. The percent of AA and A grade eggs, when stored at 71°F., dropped from 9 8 . 1 % and 1.9% respectively when new laid, to 2 9 . 1 % and 6 9 . 1 % after 2 days; 7.3% and 61.8% after 7 days; 0 % a n d . 50.9% after 14 days; 0 % and 27.2% after 21 days; and 0 % and 5.5% after 28 days. Similarly the percent of AA and A grade eggs stored at 50°F. to 55°F. dropped from 9 8 . 1 % and 1.9% to 96.4% and 3.6% after 2 days; 6 9 . 1 % and 2 9 . 1 % after 7 days; 36.4% and 61.8% after 14 days; 30.9% and 6 9 . 1 % after 21 days; and 14.6% and 7 8 . 1 % after 28 days.
TRAIL
313
EGG INTERIOR QUALITY
in quality than the 2 day old eggs stored at normal temperatures, while all three conditions and periods of storage gave between 98% and 100% of eggs in grades AA and A.
at 55°F. were not significantly lower in interior quality than, and graded out as well as, two day old eggs stored at the normal temperature of 71°F. ACKNOWLEDGMENT
SUMMARY
The author wishes to thank the Director of Veterinary Services and Animal Industry for permission to publish this paper. REFERENCES Brant, A. W., A. W. Otte and K. H. Norris, 1951. Recommended standards for scoring and measuring open egg quality. Food Tech. 5: 356-361. Duncan, D. B., 1955. Multiple range and multiple F Tests. Biometrics, 11: 1-42. Fry, J. L., and G. W. Newell, 1957. Management and holding conditions as they affect the interior quality of eggs. Poultry Sci. 36: 240-246. Haugh, R. R., 1937. The Haugh unit for measuring egg quality. U. S. Egg Poultry Mag. 43: 552555, 572-573. Nordskog, A. W., and 0. Cotterill, 1953. Breeding for egg quality. 2. Sampling hens for interior quality. Poultry Sci. 32: 1052-1054. Wesley, R. L., and W. J. Stadelman, 1959. Measurements of interior egg quality. Poultry Sci. 38: 474-481.
A Biological Assay for Metabolizable Energy in Poultry Feed Ingredients Together With Findings Which Demonstrate Some of the Problems Associated With the Evaluation of Fats I . R . SlBBALD AND S. J . SLINGER Departments of Nutrition and Poultry Science, Ontario Agricultural College, Guelpk, Ontario, Canada (Received for publication August 17, 1962)
I
N 1958 a programme was initiated at this institution, the objective of which was to obtain metabolizable energy (M.E.) values for representative samples of all feedingstuffs of practical importance to the Canadian poultry industry. Prelim-
inary studies were designed to test two basic assumptions: 1) that the M.E. value of an ingredient is independent of the other diet components, and 2) that the value remains relatively constant irrespective of the age of type of bird to which
Downloaded from http://ps.oxfordjournals.org/ by guest on April 9, 2015
The relative effect of storage time and refrigerated and normal temperature holding on egg interior quality in Uganda was studied. Haugh units were used to measure the broken out quality of eggs stored at 71°F. and 50°F. to 55°F. for 2, 7, 14, 21 and 28 day periods. Eggs stored at 50°F. to 55°F. for all periods up to and including 28 days had significantly better interior quality than eggs stored at 71°F. for 7 or more days. The eggs were graded and the most suitable systems of holding and marketing suggested, to allow the highest quality eggs to be made available. Once weekly marketing of eggs stored at 55°F. was recommended as the most practical method of getting highest quality eggs into circulation, although it was noted that 14 and 21 day old eggs stored