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Effects of Oil Treating on Shell Egg Quality During Short Term Refrigerated Storage
RESTRICTED FEEDING
ACKNOWLEDGMENT
The authors wish to thank Mr. P. J. McGann for his technical assistance with this experiment.
REFERENCES Gowe, R. S., A. S. Johnson, R. D. Crawford, J. H. Downs, A. T. Hill, W. F. Mountain, J. R. Peletier and J. H. Strain, 1960. Restricted versus full-feeding during the growing period for egg production stock. Brit. Poultry Sci. 1: 37-56. Maclntyre, T. M., and J. R. Aitken, 1959. The performance of laying hens reared on restricted and full feeding programs. Can. J. Animal Sci. 39: 217-225. Ringrose, R. C , 1958. Restricted feeding of growing pullets. New Hampshire Agr. Exp. Sta. Bui. 456. Sherwood, D. H., and T. T. Milby, 1954. Restricted versus full-feeding for growing pullets. Poultry Sci. 33: 1080. Sunde, M. L., W. W. Cravens, H. R. Bird and J. G. Halpin, 1954. The effect of complete and incomplete growing diets on subsequent performance of the laying hen. Poultry Sci. 33: 779-784. Tomhave, A E., 1958. The effect of restricted feeding of pullets during the growing period on subsequent laying house performance. Delaware Agr. Exp. Sta. Bui. (Tech.) 326. Walter, E. D., and J. R. Aitken, 1961. The performance of laying hens subjected to restricted feeding during the rearing and laying periods. Poultry Sci. 40: 345-354.
Effects of Oil Treating on Shell Egg Quality During Short Term Refrigerated Storage D. V. SCHWALL, F. A. GARDNER AND E. D. PARNELL Texas A. and M. College, College Station, Texas (Received for publication June 23, 1960)
INTRODUCTION
/^VPTIMUM short term holding temper^S atures for retaining tin interior ouality of shell eggs have been studied by many workers, Dawson and Hall (1954), Fry and Newell (1957), Parnell and Jaska (1958). The temperature usually recommended for short term storage periods has been around 45° to 55°F. The process of oiling shell eggs for long term storage has been used extensively for many years, Spamer (1931), and has been
receiving renewed attention recently as a method of retaining quality during short holding periods, Swanson et al. (1958), Stadelman and Wilson (1958). These recent studies have considered the merits of various methods of applying the oil to the shell. This study was conducted to determine whether oiling shell eggs for subsequent short storage periods of one to 21 days would be of significant value if the eggs are to be held under the recommended refrigerated conditions.
Downloaded from http://ps.oxfordjournals.org/ by guest on December 4, 2014
stricted-fed birds laid more eggs in the first production year (to 500 days). Following a forced-moult the restricted birds came into production more quickly and again laid at a higher rate throughout the second production year. In one of two experiments the egg size of the restricted-fed birds was less than in the full-fed birds during the first production year and in the other experiment no differences occurred. The egg mass laid by the restricted birds was larger for both experiments once the birds had come into full egg production. Restricted-fed birds in their second production year laid larger eggs than full-fed birds. The mortality in the restricted groups was higher during the period the feed was restricted but it was lower throughout both the first and second production years.
583
584
D. V. SCHWALL, F. A. GARDNER AND E. D. PARNELL EXPERIMENTAL PROCEDURE
RESULTS AND DISCUSSION
Haugh Units. An overall average of 81.0 Haugh units was obtained from an initial 20 egg sample taken from each of the six tests on the day the eggs were laid. There was no significant difference at the one percent level of probability between the initial Haugh unit averages. Untreated eggs lost interior quality faster than the oil treated eggs (Table 1). After
TABLE 1.—Average Haugh units observed in six tests during 21 days of storage under four refrigerated conditions when eggs wsre untreated or shell treated with oil Storage conditions Treatment
Temp. Relative Degrees F. humidity
Days of storage 1 1
3
7
14
21
None
45 45 55 55
Low High Low High Average:
74.1 71.0 71.3 72.7 72.3**
73.0 70.0 66.5 69.8 69.8**
70.2 67.5 61.9 66.4 66.5**
68.0 66.0 56.3 65.3 63.9**
65.4 65.1 52.7 60.4 60.9**
Oil Spray
45 45 55 55
Low High Low High Average:
80.1 79.6 78.3 78.4 79.1
80.8 81.4 77.6 79.0 79.7
79.8 77.1 75.8 75.7 77.1
79.8 77.0 74.8 74.2 76.4
73.9 73.8 71.7 73'. 8 73.3
Oil Dip
45 45 55 55
Low High Low Nigh Average:
79.2 80.2 78.0 78.5 79.0
79.8 78.6 78.2 79.4 79.0
78.1 76.8 76.5 77.4 77.2
77.5 76.1 76.6 76.3 76.6
75.0 74.1 73.4 74.4 74.2
** Significantly lower than the oil treated groups at the .01 level. Initial Haugh unit average was 81.0.
1
Downloaded from http://ps.oxfordjournals.org/ by guest on December 4, 2014
Six tests were conducted during June and July, 1959, using a total of 3360 eggs from incross pullets. The hens were housed in individual wire cages and fed the basal laying ration of the Texas A. and M. poultry farm. The eggs were gathered in wire baskets twice daily and placed in a walk-in cooler at an average temperature of 55°F. All eggs were candled daily to remove cracked or misshapen eggs and were then randomly placed into treatment groups. One group was kept as an untreated control. The oil dipped eggs were completely immersed in a clear mineral oil at room temperature and then placed on filler flats. The oil spray was applied with a commercially available aerosol applicator from a constant height of 12 inches above the eggs. The eggs were then individually weighed to the nearest 0.001 gram and each group randomly divided into four storage conditions. The conditions used were: (1) 45°F. and a low relative humidity; (2) 45°F. and a high relative humidity; (3) 55°F. and a
low relative humidity; (4) 55°F. and a high relative humidity. Nine eggs from each treatment group were removed from each storage condition, after 1, 3, 7, 14 and 21 days of storage. Weight loss, albumen pH and Haugh unit determinations were made. Haugh units were measured by the procedure outlined by Brant et al. (1951). The yolk and white were then separated and the albumen of each nine egg treatment group mixed thoroughly and the pH measured with a Beckman model G pH meter.
OIL TREATMENT AND EGG QUALITY
585 USDA Grade
Haugh Units
45°
55°
Untreated
•
Oil sprayed
O
Oil dipped
A
FIG. 1. Average Haugh units observed during 21 days of storage when eggs were untreated or oil treated and held at 45 °F. and 55 °F.
one day of storage, the difference observed in Haugh units was significant at the one percent level of probability and remained significant throughout the 21 day storage period. The difference in the rate of Haugh unit decrease between the two oil treatments was not significant. The difference between 45°F. and 55°F. affected the rate of Haugh unit loss in the untreated eggs, but the oil treated eggs were not signifi-
cantly affected (Figure 1). The difference in humidity had little effect on the Haugh units observed. The results of this test substantiate the observations of Cotterill et al. (1958) that low temperatures alone are not adequate in preventing a decline in albumen quality. This study is in agreement with results obtained by many workers who have shown that oil coating is beneficial in retaining
Downloaded from http://ps.oxfordjournals.org/ by guest on December 4, 2014
Days of Storage
586
D. V. SCHWALL, F. A. GARDNER AND E. D. PARNELL
groups. The rate of weight loss was not significantly different between the oil treating methods. Low humidity significantly increased the loss in weight of untreated eggs after one week of storage. Albumen pH. The pH of the albumen was measured to determine the extent of C0 2 loss through the shell. The average initial albumen pH observed was 7.90. Figure 2 illustrates the average rate of change in albumen pH observed in this study. During storage the main pH difference occurred between the untreated and the oil treated groups (significant at the one percent level of probability) but there was also a significant difference at the five percent level between the oil spray and the oil dipped treatments. The pH difference between oiling methods was probably due to the application procedure in that dipping afforded a more complete coating on each egg. The temperature or humidity of the storage conditions did not significantly affect the albumen pH. Even though temperature will effect the albumen pH (Cotterill and Gardner, 1957) the refrigerated tempera-
TABLE 2.—Average individual egg weight loss in grams observed in six tests during 21 days of storage under four refrigerated conditions when eggs were untreated or treated with oil Storage conditions Treatment
Days of storage Relative Temp. Degrees F . humidity
1
3
7
14
21
1.032 .746 1.690 .497 991**
1.565 1.003 2.331 .715 1.403**
None
45 45 55 55
Low High Low High Average:
.177 .178 .236 .124 .179**
.298 .266 .442 .180 .340**
.546 .445 .836 .284 .528**
Oil Spray
45 45 55 55
Low High Low High Average:
.068 .061 .066 .053 .062
.108 .080 .108 .072 .092
.108 .122 .147 .081 .114
.134 .122 .187 .094 .134
.193 .166 .287 .121 ,192
Oil Dip
45 45 55 55
Low High Low High Average:
.054 .051 .056 .040 .050
.074 .059 .081 .047 .065
.098 .087 .111 .065 .090
.124 .097 .145 .084 .113
.165 .130 .210 .099 .153
** Significantly greater than the oil treated groups at the 1 percent level of probability.
Downloaded from http://ps.oxfordjournals.org/ by guest on December 4, 2014
C0 2 which retards the loss of Haugh units and further shows that either the spray or dip method of application is of significant value when eggs are held under refrigerated conditions. U.S.D.A. Grades. Since many egg handlers will soon be using the Fresh Fancy or AA Grade quality based on provisions printed in the Federal Register (19S9), this study was carried out in a manner conforming to the Fresh Fancy program. The findings of this study show that oil treated eggs maintained Fresh Fancy or AA Grade quality for 21 days while most of the untreated eggs declined to Grade A after only three days of storage (Figure 1). Weight Loss. Shell treating by either the oil spray or oil dip method significantly reduced the weight loss in eggs held under all of the storage conditions as compared to eggs not oiled. The difference became significant after one day of storage and continued throughout the entire period (Table 2). Temperature and humidity had a greater effect on weight loss in the untreated eggs than in either of the oil treated
OIL TREATMENT AND EGG QUALITY
587
Oil Dip FIG. 2. Average albumen pH observed during 21 days of storage when eggs were untreated or oil treated and held at 4S°F. to SS°F.
ture ranges used in this study were not sufficient to produce a significant difference. SUMMARY AND CONCLUSIONS Thirty-three hundred and sixty eggs were selected at random from one age of incross hens to determine whether shell treating eggs with oil would be beneficial when eggs are held under refrigeration for short periods. Some eggs were oil sprayed or oil dipped on the day of lay and then stored under four holding conditions ranging from 4S°F. to 55°F. and relative humidities of 45 to 78 percent for periods up to 21 days of storage and compared with similar eggs that were untreated. Observations made during the study were as follows: (1) Untreated eggs lost significantly more interior quality and weight than eggs treated by either method of oiling under all of the refrigerated conditions. This significan difference became apparent after one
day of storage. (2) There was no significant difference between the oil spray or oil dip method of shell treating eggs as a means for preserving Haugh units or avoiding weight loss. (3) Oil treating maintained Fresh Fancy or Grade AA interior quality for 21 days or longer under the refrigerated conditions of this study while untreated eggs dropped to Grade A in most cases after three days of storage. (4) The pH of untreated eggs increased significantly faster than the oil treated eggs. The rate of pH change between the two oiling methods was also significant at the five percent level of probability. (5) Low humidity increased the weight loss in untreated eggs, but did not significantly affect eggs that were oil treated. This study indicates that oil treating shell eggs during short term refrigerated storage has a significant value, especially
Downloaded from http://ps.oxfordjournals.org/ by guest on December 4, 2014
Untreated Oil Spray
588
D. V. SCHWALL, F. A. GARDNER AND E. D. PARNEIX
if eggs are marketed under a quality control program. The difference in rate of quality deterioration was probably due to the retention of C0 2 and moisture by the oil treated eggs. REFERENCES
The Effect of Unidentified Growth Factor Sources and Restricted Feeding on the Performance of Egg Strain Chickens W. F. PEPPER, S. J. SLINGER AND G. C. ASHTON Departments of Poultry Science and Physics (Statistics), Ontario Agricultural College, Guelph, Ontario, Canada (Received for publication June 27, 1960)
A
GOOD deal of evidence has accumulated in the literature to indicate the need by growing chicks of unidentified growth factors (UGF) found in certain natural feedingstuffs including fish meals, meat meals and dried whey. In previous studies conducted in our laboratory (Summers et al., 1959a, b) it was found that fish meals and meat meals are not reliable sources of UGF for the chick. Dried whey gave a fairly consistent UGF response but did not supply UGF activity not present in fish solubles. Variable results have been reported concerning the need for UGF by mature hens.
Couch et al. (1950) reported that liver fraction "L" contained an unidentified factor necessary for maximum hatchability. Dieckert and Couch (1951) found a hatchability response using whole liver, various fractions of liver "L" and Difco yeast as inclusions in a purified diet. Stephenson and Clower (1952) and Arscott and Combs (1953) presented evidence for an unidentified hatchability factor in fish solubles. In contrast to these reports Grau and Zweigart (1952) found that suplementing a purified diet with liver "L" did not improve hatchability while Patterson (1955) found that neither dried whey, liver meal,
Downloaded from http://ps.oxfordjournals.org/ by guest on December 4, 2014
Brant, A. W., A. W. Otte and K. H. Norris, 1951. Recommended standards for scoring and measuring opened egg quality. Food Technology, 5: 356-361. Cotterill, O. J., and F. A. Gardner, 1957. Retarding thick white deterioration by holding eggs in sealed containers. Poultry Sci. 36: 196-206. Cotterill, O. J., F. A. Gardner, E. M. Funk and F. E. Cunningham, 1958. Relationship between temperature and carbon dioxide loss from shell eggs. Poultry Sci. 37: 479-483. Dawson, L. E., and C. W. Hall, 1954. Relationship between rate of cooling, holding container and egg albumen quality of eggs. Poultry Sci. 33: 624-628.
Federal Register, 1959. Amendments. U.S.D.A., A.M.S., Poultry Division, Regulations and standards for grading and inspection of shell eggs under the farm products inspection act., Aug. 15, 1959. 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. Parnell, E. D., and R. C. Jaska, 1958. Temperature and relative humidity effects on market egg quality. Texas Ag. Exp. Sta. Bui. MP 296, p. 4. Stadelman, W. J., and M. L. Wilson, 1958. An oil dispensing aerosol for quality preservation of shell eggs. Poultry Sci. 37: 731-733. Spamer, C. O., 1931. Historic methods and present practices of preserving eggs in Holland. U.S. Egg Poultry Magazine, 37 ( 2 ) : 48-51. Swanson, M. H., G. W. Froning and D. N. Hendrickson, 1958. Effectiveness of shell treating eggs on day of lay as influenced by quality of sealer and method of application. Poultry Sci. 37: 1246.
ACKNOWLEDGMENT
The authors wish to thank Mr. P. J. McGann for his technical assistance with this experiment.
REFERENCES Gowe, R. S., A. S. Johnson, R. D. Crawford, J. H. Downs, A. T. Hill, W. F. Mountain, J. R. Peletier and J. H. Strain, 1960. Restricted versus full-feeding during the growing period for egg production stock. Brit. Poultry Sci. 1: 37-56. Maclntyre, T. M., and J. R. Aitken, 1959. The performance of laying hens reared on restricted and full feeding programs. Can. J. Animal Sci. 39: 217-225. Ringrose, R. C , 1958. Restricted feeding of growing pullets. New Hampshire Agr. Exp. Sta. Bui. 456. Sherwood, D. H., and T. T. Milby, 1954. Restricted versus full-feeding for growing pullets. Poultry Sci. 33: 1080. Sunde, M. L., W. W. Cravens, H. R. Bird and J. G. Halpin, 1954. The effect of complete and incomplete growing diets on subsequent performance of the laying hen. Poultry Sci. 33: 779-784. Tomhave, A E., 1958. The effect of restricted feeding of pullets during the growing period on subsequent laying house performance. Delaware Agr. Exp. Sta. Bui. (Tech.) 326. Walter, E. D., and J. R. Aitken, 1961. The performance of laying hens subjected to restricted feeding during the rearing and laying periods. Poultry Sci. 40: 345-354.
Effects of Oil Treating on Shell Egg Quality During Short Term Refrigerated Storage D. V. SCHWALL, F. A. GARDNER AND E. D. PARNELL Texas A. and M. College, College Station, Texas (Received for publication June 23, 1960)
INTRODUCTION
/^VPTIMUM short term holding temper^S atures for retaining tin interior ouality of shell eggs have been studied by many workers, Dawson and Hall (1954), Fry and Newell (1957), Parnell and Jaska (1958). The temperature usually recommended for short term storage periods has been around 45° to 55°F. The process of oiling shell eggs for long term storage has been used extensively for many years, Spamer (1931), and has been
receiving renewed attention recently as a method of retaining quality during short holding periods, Swanson et al. (1958), Stadelman and Wilson (1958). These recent studies have considered the merits of various methods of applying the oil to the shell. This study was conducted to determine whether oiling shell eggs for subsequent short storage periods of one to 21 days would be of significant value if the eggs are to be held under the recommended refrigerated conditions.
Downloaded from http://ps.oxfordjournals.org/ by guest on December 4, 2014
stricted-fed birds laid more eggs in the first production year (to 500 days). Following a forced-moult the restricted birds came into production more quickly and again laid at a higher rate throughout the second production year. In one of two experiments the egg size of the restricted-fed birds was less than in the full-fed birds during the first production year and in the other experiment no differences occurred. The egg mass laid by the restricted birds was larger for both experiments once the birds had come into full egg production. Restricted-fed birds in their second production year laid larger eggs than full-fed birds. The mortality in the restricted groups was higher during the period the feed was restricted but it was lower throughout both the first and second production years.
583
584
D. V. SCHWALL, F. A. GARDNER AND E. D. PARNELL EXPERIMENTAL PROCEDURE
RESULTS AND DISCUSSION
Haugh Units. An overall average of 81.0 Haugh units was obtained from an initial 20 egg sample taken from each of the six tests on the day the eggs were laid. There was no significant difference at the one percent level of probability between the initial Haugh unit averages. Untreated eggs lost interior quality faster than the oil treated eggs (Table 1). After
TABLE 1.—Average Haugh units observed in six tests during 21 days of storage under four refrigerated conditions when eggs wsre untreated or shell treated with oil Storage conditions Treatment
Temp. Relative Degrees F. humidity
Days of storage 1 1
3
7
14
21
None
45 45 55 55
Low High Low High Average:
74.1 71.0 71.3 72.7 72.3**
73.0 70.0 66.5 69.8 69.8**
70.2 67.5 61.9 66.4 66.5**
68.0 66.0 56.3 65.3 63.9**
65.4 65.1 52.7 60.4 60.9**
Oil Spray
45 45 55 55
Low High Low High Average:
80.1 79.6 78.3 78.4 79.1
80.8 81.4 77.6 79.0 79.7
79.8 77.1 75.8 75.7 77.1
79.8 77.0 74.8 74.2 76.4
73.9 73.8 71.7 73'. 8 73.3
Oil Dip
45 45 55 55
Low High Low Nigh Average:
79.2 80.2 78.0 78.5 79.0
79.8 78.6 78.2 79.4 79.0
78.1 76.8 76.5 77.4 77.2
77.5 76.1 76.6 76.3 76.6
75.0 74.1 73.4 74.4 74.2
** Significantly lower than the oil treated groups at the .01 level. Initial Haugh unit average was 81.0.
1
Downloaded from http://ps.oxfordjournals.org/ by guest on December 4, 2014
Six tests were conducted during June and July, 1959, using a total of 3360 eggs from incross pullets. The hens were housed in individual wire cages and fed the basal laying ration of the Texas A. and M. poultry farm. The eggs were gathered in wire baskets twice daily and placed in a walk-in cooler at an average temperature of 55°F. All eggs were candled daily to remove cracked or misshapen eggs and were then randomly placed into treatment groups. One group was kept as an untreated control. The oil dipped eggs were completely immersed in a clear mineral oil at room temperature and then placed on filler flats. The oil spray was applied with a commercially available aerosol applicator from a constant height of 12 inches above the eggs. The eggs were then individually weighed to the nearest 0.001 gram and each group randomly divided into four storage conditions. The conditions used were: (1) 45°F. and a low relative humidity; (2) 45°F. and a high relative humidity; (3) 55°F. and a
low relative humidity; (4) 55°F. and a high relative humidity. Nine eggs from each treatment group were removed from each storage condition, after 1, 3, 7, 14 and 21 days of storage. Weight loss, albumen pH and Haugh unit determinations were made. Haugh units were measured by the procedure outlined by Brant et al. (1951). The yolk and white were then separated and the albumen of each nine egg treatment group mixed thoroughly and the pH measured with a Beckman model G pH meter.
OIL TREATMENT AND EGG QUALITY
585 USDA Grade
Haugh Units
45°
55°
Untreated
•
Oil sprayed
O
Oil dipped
A
FIG. 1. Average Haugh units observed during 21 days of storage when eggs were untreated or oil treated and held at 45 °F. and 55 °F.
one day of storage, the difference observed in Haugh units was significant at the one percent level of probability and remained significant throughout the 21 day storage period. The difference in the rate of Haugh unit decrease between the two oil treatments was not significant. The difference between 45°F. and 55°F. affected the rate of Haugh unit loss in the untreated eggs, but the oil treated eggs were not signifi-
cantly affected (Figure 1). The difference in humidity had little effect on the Haugh units observed. The results of this test substantiate the observations of Cotterill et al. (1958) that low temperatures alone are not adequate in preventing a decline in albumen quality. This study is in agreement with results obtained by many workers who have shown that oil coating is beneficial in retaining
Downloaded from http://ps.oxfordjournals.org/ by guest on December 4, 2014
Days of Storage
586
D. V. SCHWALL, F. A. GARDNER AND E. D. PARNELL
groups. The rate of weight loss was not significantly different between the oil treating methods. Low humidity significantly increased the loss in weight of untreated eggs after one week of storage. Albumen pH. The pH of the albumen was measured to determine the extent of C0 2 loss through the shell. The average initial albumen pH observed was 7.90. Figure 2 illustrates the average rate of change in albumen pH observed in this study. During storage the main pH difference occurred between the untreated and the oil treated groups (significant at the one percent level of probability) but there was also a significant difference at the five percent level between the oil spray and the oil dipped treatments. The pH difference between oiling methods was probably due to the application procedure in that dipping afforded a more complete coating on each egg. The temperature or humidity of the storage conditions did not significantly affect the albumen pH. Even though temperature will effect the albumen pH (Cotterill and Gardner, 1957) the refrigerated tempera-
TABLE 2.—Average individual egg weight loss in grams observed in six tests during 21 days of storage under four refrigerated conditions when eggs were untreated or treated with oil Storage conditions Treatment
Days of storage Relative Temp. Degrees F . humidity
1
3
7
14
21
1.032 .746 1.690 .497 991**
1.565 1.003 2.331 .715 1.403**
None
45 45 55 55
Low High Low High Average:
.177 .178 .236 .124 .179**
.298 .266 .442 .180 .340**
.546 .445 .836 .284 .528**
Oil Spray
45 45 55 55
Low High Low High Average:
.068 .061 .066 .053 .062
.108 .080 .108 .072 .092
.108 .122 .147 .081 .114
.134 .122 .187 .094 .134
.193 .166 .287 .121 ,192
Oil Dip
45 45 55 55
Low High Low High Average:
.054 .051 .056 .040 .050
.074 .059 .081 .047 .065
.098 .087 .111 .065 .090
.124 .097 .145 .084 .113
.165 .130 .210 .099 .153
** Significantly greater than the oil treated groups at the 1 percent level of probability.
Downloaded from http://ps.oxfordjournals.org/ by guest on December 4, 2014
C0 2 which retards the loss of Haugh units and further shows that either the spray or dip method of application is of significant value when eggs are held under refrigerated conditions. U.S.D.A. Grades. Since many egg handlers will soon be using the Fresh Fancy or AA Grade quality based on provisions printed in the Federal Register (19S9), this study was carried out in a manner conforming to the Fresh Fancy program. The findings of this study show that oil treated eggs maintained Fresh Fancy or AA Grade quality for 21 days while most of the untreated eggs declined to Grade A after only three days of storage (Figure 1). Weight Loss. Shell treating by either the oil spray or oil dip method significantly reduced the weight loss in eggs held under all of the storage conditions as compared to eggs not oiled. The difference became significant after one day of storage and continued throughout the entire period (Table 2). Temperature and humidity had a greater effect on weight loss in the untreated eggs than in either of the oil treated
OIL TREATMENT AND EGG QUALITY
587
Oil Dip FIG. 2. Average albumen pH observed during 21 days of storage when eggs were untreated or oil treated and held at 4S°F. to SS°F.
ture ranges used in this study were not sufficient to produce a significant difference. SUMMARY AND CONCLUSIONS Thirty-three hundred and sixty eggs were selected at random from one age of incross hens to determine whether shell treating eggs with oil would be beneficial when eggs are held under refrigeration for short periods. Some eggs were oil sprayed or oil dipped on the day of lay and then stored under four holding conditions ranging from 4S°F. to 55°F. and relative humidities of 45 to 78 percent for periods up to 21 days of storage and compared with similar eggs that were untreated. Observations made during the study were as follows: (1) Untreated eggs lost significantly more interior quality and weight than eggs treated by either method of oiling under all of the refrigerated conditions. This significan difference became apparent after one
day of storage. (2) There was no significant difference between the oil spray or oil dip method of shell treating eggs as a means for preserving Haugh units or avoiding weight loss. (3) Oil treating maintained Fresh Fancy or Grade AA interior quality for 21 days or longer under the refrigerated conditions of this study while untreated eggs dropped to Grade A in most cases after three days of storage. (4) The pH of untreated eggs increased significantly faster than the oil treated eggs. The rate of pH change between the two oiling methods was also significant at the five percent level of probability. (5) Low humidity increased the weight loss in untreated eggs, but did not significantly affect eggs that were oil treated. This study indicates that oil treating shell eggs during short term refrigerated storage has a significant value, especially
Downloaded from http://ps.oxfordjournals.org/ by guest on December 4, 2014
Untreated Oil Spray
588
D. V. SCHWALL, F. A. GARDNER AND E. D. PARNEIX
if eggs are marketed under a quality control program. The difference in rate of quality deterioration was probably due to the retention of C0 2 and moisture by the oil treated eggs. REFERENCES
The Effect of Unidentified Growth Factor Sources and Restricted Feeding on the Performance of Egg Strain Chickens W. F. PEPPER, S. J. SLINGER AND G. C. ASHTON Departments of Poultry Science and Physics (Statistics), Ontario Agricultural College, Guelph, Ontario, Canada (Received for publication June 27, 1960)
A
GOOD deal of evidence has accumulated in the literature to indicate the need by growing chicks of unidentified growth factors (UGF) found in certain natural feedingstuffs including fish meals, meat meals and dried whey. In previous studies conducted in our laboratory (Summers et al., 1959a, b) it was found that fish meals and meat meals are not reliable sources of UGF for the chick. Dried whey gave a fairly consistent UGF response but did not supply UGF activity not present in fish solubles. Variable results have been reported concerning the need for UGF by mature hens.
Couch et al. (1950) reported that liver fraction "L" contained an unidentified factor necessary for maximum hatchability. Dieckert and Couch (1951) found a hatchability response using whole liver, various fractions of liver "L" and Difco yeast as inclusions in a purified diet. Stephenson and Clower (1952) and Arscott and Combs (1953) presented evidence for an unidentified hatchability factor in fish solubles. In contrast to these reports Grau and Zweigart (1952) found that suplementing a purified diet with liver "L" did not improve hatchability while Patterson (1955) found that neither dried whey, liver meal,
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Brant, A. W., A. W. Otte and K. H. Norris, 1951. Recommended standards for scoring and measuring opened egg quality. Food Technology, 5: 356-361. Cotterill, O. J., and F. A. Gardner, 1957. Retarding thick white deterioration by holding eggs in sealed containers. Poultry Sci. 36: 196-206. Cotterill, O. J., F. A. Gardner, E. M. Funk and F. E. Cunningham, 1958. Relationship between temperature and carbon dioxide loss from shell eggs. Poultry Sci. 37: 479-483. Dawson, L. E., and C. W. Hall, 1954. Relationship between rate of cooling, holding container and egg albumen quality of eggs. Poultry Sci. 33: 624-628.
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