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Increasing Shelf-Life of Fresh Chicken Meat by Using Chlorination*
CHLORINATION OF POULTRY MEAT shell. Poultry Sci. 24:159-167. Hinshaw, W. R., and E. McNeil, 1943. Experiments with sulfanilamide for turkeys. Poultry Sci. 22: 291-294. Mann, T., and D. Keilin, 1940. Sulfanilamide as a specific inhibitor of carbonic anhydrase. Nature, 146: 164-165.
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Scott, H. M., E. Jungherr and L. D. Matterson, 1944. The effect of feeding sulfanilamide to the laying fowl. Poultry Sci. 23:446-453. Tyler, C , 1950. The effect of sulphanilamide on the metabolism of calcium, carbonate, phosphorus chloride, and nitrogen in the laying hen. British J. Nutrition, 4:112-128.
FRANK ZIEGLER AND W. J. STADELMAN State College of Washington, Pullman (Received for publication April 28, 1955)
R
EPORTS in the literature generally agree that the spoilage of chicken meat is due to bacterial growth on the surface of the bird. Therefore, anything which tends to increase or decrease the bacterial population will affect shelf-life adversely or beneficially, respectively. Sanitation in the processing plant is recognized as a "must" in decreasing bacterial populations which is necessary if satisfactory shelf-life is to be obtained with fresh cut-up poultry meat. Chlorine has long been accepted as a suitable means for reducing bacterial growth in water. High concentrations of chlorine are used for disinfecting equipment. With this history of using chlorine for controlling bacterial growth the application of chorinated water in poultry processing plants resulted. The purpose of this study was to determine how much increase in shelf-life could be obtained by using chlorinated water for cooling birds and for rinsing birds just prior to packaging. The effects of inplant chlorination in poultry processing plants were pointed * Scientific Paper No. 1410, Washington Agricultural Experiment Stations, Pullman. Project No. 1076.
out by Goresline, Howe, Baush and Gunderson (1951) and Miller (1953). They reported an increased shelf life, much lower bacteria counts on the product, reduced odors in the plant, and a reduction of slime on equipment resulted from using chlorinated water containing approximately 20 parts per million of available chlorine. Drewniak, Howe, Goresline and Baush (1954) found that inplant chlorination at 10, 20 and 45 ppm. concentrations in processing water was exceptionally effective for decreasing bacterial counts. It lowered the bacterial counts on equipment and on poultry carcasses; eliminated slime, corrosion, and plant odors; cleared corroded pipes and nozzles; and reduced clean-up time and labor by more than 33 percent. They found that snow made from chlorinated water did not prove to be any more effective as a sanitizing agent than did snow made from plain water. EXPERIMENTAL PROCEDURE
This study consisted of three experiments with suitable replication. Each replicate in each of the experiments consisted of 12 birds. Twelve halves (one from each bird) were used in the control groups which were cooled in ice water con-
Downloaded from http://ps.oxfordjournals.org/ at University of Nebraka-Lincoln Libraries on April 13, 2015
Increasing Shelf-Life of Fresh Chicken Meat by Using Chlorination*
1390
F . ZlEGLER AND W. J. STADELMAN
In experiment 3, the processing was done by the sub-scald (140°F. water for 40 seconds) method. Except for this variation and the fact that 2 rather than 3 replicates were made, this experiment was similar to experiment 1. Chlorine concentrations at the beginning and at the end of the treatments are reported in Table 1. The residual chlorine concentrations were determined with a Wallace and Tiernan comparator set. Shelf-like was determined by appearance of off-odor as detected by organolep-
TABLE 1.—Residual chlorine content of water in parts per million before and after treatment Exp. No.
Before
After
Before
After
1 2 3
10.0 10.0 10.0
0.18 3.7 1.0
20.0 20.0 20.0
0.40 10.0 1.5
tic techniques and by appearance of slime as detected by scrapings by the procedure reported by Ziegler, Spencer and Stadelman (1954). After the cooling period or the dipping, each half was packaged in a polyethylene bag and placed in a 34°F. refrigerator. Observations on odor and slime were made starting the sixth day after processing. They were continued on alternate days until the first spoilage was noticed in any treatment group, after which time they were made daily. RESULTS AND DISCUSSION
The shelf-life as determined by detection of off-odor of chickens in the three experiments is summarized in Table 2. Similar data for appearance of slime are also listed in Table 2. These data were analyzed by analysis of variance procedure. The differences between control and treated halves in experiment 1 were found to be significant at the 1 percent level. Actual differences were found to be over 2 days' increase in shelf life as determined by either odor or slime with use of 10 or 20 ppm. chlorine. TABIE 2.—Number of days to spoilage of fresh chicken held at 34"F. packaged in polyethylene; replicate averages OS odor Chlorine Con- 10 Con- 20 trol ppm. trol ppm.
Con- 10 Con- 20 trol ppm. trol ppm.
Slime
Experiment 1 12.8 15.2 12.7 15.5 2 12.7 13.6 13.3 13.8 3 12.2 13.3 12.5 13.9
10.5 12.4 10.1 12.6 10.1 10.6 10.7 10.8 10.0 10.1 9.9 10.8
Downloaded from http://ps.oxfordjournals.org/ at University of Nebraka-Lincoln Libraries on April 13, 2015
taining less than 0.5 ppm. chlorine. Six of the other halves in each replicate were cooled or dipped, as the particular experiment called for, in ice water which contained 10 ppm. of total residual chlorine. Six other halves were cooled or dipped in ice water containing 20 ppm. of residual chlorine. Approximately 800 grams of water and ice were used for cooling each half of each bird. Cooling of all halves of chicken in each treatment group was done in a single container of 5 kilograms of ice and water for chlorine treatments and 10 kilograms of ice and water for the control group. Cooling time was 2 hours. In experiments 1 and 2, birds were processed by semi-scald procedures using 128°F. water for 40 seconds. They were eviscerated immediately. Necks and backs were removed to simplify splitting the birds into uniform halves. In experiment 1, the halves were cooled in either the control group or in the treatment groups, actually cooling in chlorinated water containing 10 or 20 ppm. No attempt was made to replace the chlorine as the concentration decreased during the cooling period. In the second experiment, all halves were cooled for 2 hours in ice water. Then the treatment halves were dipped for 5 minutes into 10 or 20 ppm. chlorinated ice water.
CHLORINATION OF POULTRY MEAT
From these data, it is apparent that cooling of chickens in 10 or 20 ppm. chlorine water is an effective means of increasing shelf-life. Such a procedure could be followed in small processing plants which are not equipped with the inplant chlorination systems such as described by Miller (1953) and Goresline et al. (1951). The additional benefits of the inplant chlorination listed in the literature review should not be overlooked. The use of chlorine for a dip just prior to packaging did not appear to be a satisfactory means for increasing shelf-life
of poultry meat appreciably. SUMMARY
Ninety-six chicken fryers were used to check the effect of chlorine in the cooling water or in rinse water on shelf-life. All birds were split into halves so that paired comparisons between halves of the same chicken could be used for control and treated groups. It was found that chlorine used in the cooling water significantly increased shelflife as determined by off-odor or appearance of slime. The use of chlorine dip gave statistically significant difference in appearance of odor but no significant difference in appearance of slime. The differences were of such small magnitude to be of no practical importance. Use of chlorine cooling water had considerably more effect on shelf-life of birds processed at 128°F. than on those processed at 140°F. ACKNOWLEDGEMENTS
The chlorination equipment and measuring devices were supplied by Wallace and Tiernan, Inc., New York. REFERENCES Drewniak, E. E., M. A. Howe, Jr., H. E. Goresline and E. R. Baush, 1954. Studies on sanitizing methods for use in poultry processing. TJ.S.D.A. Cir. No. 930. Goresline, H. E., M. A. Howe, Jr., E. R. Bausch and M. F. Gunderson, 1951. Implant chlorination does three-way job. U. S. Egg and Poultry Mag. 57(4): 12-13, 29-31. Miller, M. W., 1953. Using inplant chlorination in chilled poultry operations. Fact Finding Conference Proceedings, Institute of American Poultry Industries, 1953: 95-98. Ziegler, F., J. V. Spencer and W. J. Stadelman, 1954. A rapid method for determining spoilage in fresh poultry meat. Poultry Sci. 33:1253-1255. Ziegler, F., and W. J. Stadelman, 1955. The effect of different scald water temperatures on shelflife of fresh, non-frozen fryers. Poultry Sci. 34: 237-238.
Downloaded from http://ps.oxfordjournals.org/ at University of Nebraka-Lincoln Libraries on April 13, 2015
The differences between 10 and 20 ppm. were not significant. In experiment 2, dipping the meat for 5 minutes in the treatment solutions, differences were much smaller than in experiment 1. These differences were statistically significant with respect to off-odor but not in respect to the appearance of slime. In experiment 3, the differences in days to spoilage were not so great as in experiment 1. However, these differences were still significant at the 1 percent level when analyzed statistically. The reduced effects of chlorine treatment in this experiment as compared with those in experiment 1 may be due to difference in temperature of the scald water used in the two experiments. The differences in shelf-life of the controls processed at 128°F. as compared with those processed at 140°F. were similar in magnitude to differences reported by Ziegler and Stadelman (1955). Much greater differences were noted in the halves that were chlorine-treated. This may be due to the fact that the lower temperature scald does not do so good a job of cleansing the surface as does the high temperature scald, the shorter shelflife of high temperature scald being due to greater vulnerability of the surface to bacterial growth.
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Scott, H. M., E. Jungherr and L. D. Matterson, 1944. The effect of feeding sulfanilamide to the laying fowl. Poultry Sci. 23:446-453. Tyler, C , 1950. The effect of sulphanilamide on the metabolism of calcium, carbonate, phosphorus chloride, and nitrogen in the laying hen. British J. Nutrition, 4:112-128.
FRANK ZIEGLER AND W. J. STADELMAN State College of Washington, Pullman (Received for publication April 28, 1955)
R
EPORTS in the literature generally agree that the spoilage of chicken meat is due to bacterial growth on the surface of the bird. Therefore, anything which tends to increase or decrease the bacterial population will affect shelf-life adversely or beneficially, respectively. Sanitation in the processing plant is recognized as a "must" in decreasing bacterial populations which is necessary if satisfactory shelf-life is to be obtained with fresh cut-up poultry meat. Chlorine has long been accepted as a suitable means for reducing bacterial growth in water. High concentrations of chlorine are used for disinfecting equipment. With this history of using chlorine for controlling bacterial growth the application of chorinated water in poultry processing plants resulted. The purpose of this study was to determine how much increase in shelf-life could be obtained by using chlorinated water for cooling birds and for rinsing birds just prior to packaging. The effects of inplant chlorination in poultry processing plants were pointed * Scientific Paper No. 1410, Washington Agricultural Experiment Stations, Pullman. Project No. 1076.
out by Goresline, Howe, Baush and Gunderson (1951) and Miller (1953). They reported an increased shelf life, much lower bacteria counts on the product, reduced odors in the plant, and a reduction of slime on equipment resulted from using chlorinated water containing approximately 20 parts per million of available chlorine. Drewniak, Howe, Goresline and Baush (1954) found that inplant chlorination at 10, 20 and 45 ppm. concentrations in processing water was exceptionally effective for decreasing bacterial counts. It lowered the bacterial counts on equipment and on poultry carcasses; eliminated slime, corrosion, and plant odors; cleared corroded pipes and nozzles; and reduced clean-up time and labor by more than 33 percent. They found that snow made from chlorinated water did not prove to be any more effective as a sanitizing agent than did snow made from plain water. EXPERIMENTAL PROCEDURE
This study consisted of three experiments with suitable replication. Each replicate in each of the experiments consisted of 12 birds. Twelve halves (one from each bird) were used in the control groups which were cooled in ice water con-
Downloaded from http://ps.oxfordjournals.org/ at University of Nebraka-Lincoln Libraries on April 13, 2015
Increasing Shelf-Life of Fresh Chicken Meat by Using Chlorination*
1390
F . ZlEGLER AND W. J. STADELMAN
In experiment 3, the processing was done by the sub-scald (140°F. water for 40 seconds) method. Except for this variation and the fact that 2 rather than 3 replicates were made, this experiment was similar to experiment 1. Chlorine concentrations at the beginning and at the end of the treatments are reported in Table 1. The residual chlorine concentrations were determined with a Wallace and Tiernan comparator set. Shelf-like was determined by appearance of off-odor as detected by organolep-
TABLE 1.—Residual chlorine content of water in parts per million before and after treatment Exp. No.
Before
After
Before
After
1 2 3
10.0 10.0 10.0
0.18 3.7 1.0
20.0 20.0 20.0
0.40 10.0 1.5
tic techniques and by appearance of slime as detected by scrapings by the procedure reported by Ziegler, Spencer and Stadelman (1954). After the cooling period or the dipping, each half was packaged in a polyethylene bag and placed in a 34°F. refrigerator. Observations on odor and slime were made starting the sixth day after processing. They were continued on alternate days until the first spoilage was noticed in any treatment group, after which time they were made daily. RESULTS AND DISCUSSION
The shelf-life as determined by detection of off-odor of chickens in the three experiments is summarized in Table 2. Similar data for appearance of slime are also listed in Table 2. These data were analyzed by analysis of variance procedure. The differences between control and treated halves in experiment 1 were found to be significant at the 1 percent level. Actual differences were found to be over 2 days' increase in shelf life as determined by either odor or slime with use of 10 or 20 ppm. chlorine. TABIE 2.—Number of days to spoilage of fresh chicken held at 34"F. packaged in polyethylene; replicate averages OS odor Chlorine Con- 10 Con- 20 trol ppm. trol ppm.
Con- 10 Con- 20 trol ppm. trol ppm.
Slime
Experiment 1 12.8 15.2 12.7 15.5 2 12.7 13.6 13.3 13.8 3 12.2 13.3 12.5 13.9
10.5 12.4 10.1 12.6 10.1 10.6 10.7 10.8 10.0 10.1 9.9 10.8
Downloaded from http://ps.oxfordjournals.org/ at University of Nebraka-Lincoln Libraries on April 13, 2015
taining less than 0.5 ppm. chlorine. Six of the other halves in each replicate were cooled or dipped, as the particular experiment called for, in ice water which contained 10 ppm. of total residual chlorine. Six other halves were cooled or dipped in ice water containing 20 ppm. of residual chlorine. Approximately 800 grams of water and ice were used for cooling each half of each bird. Cooling of all halves of chicken in each treatment group was done in a single container of 5 kilograms of ice and water for chlorine treatments and 10 kilograms of ice and water for the control group. Cooling time was 2 hours. In experiments 1 and 2, birds were processed by semi-scald procedures using 128°F. water for 40 seconds. They were eviscerated immediately. Necks and backs were removed to simplify splitting the birds into uniform halves. In experiment 1, the halves were cooled in either the control group or in the treatment groups, actually cooling in chlorinated water containing 10 or 20 ppm. No attempt was made to replace the chlorine as the concentration decreased during the cooling period. In the second experiment, all halves were cooled for 2 hours in ice water. Then the treatment halves were dipped for 5 minutes into 10 or 20 ppm. chlorinated ice water.
CHLORINATION OF POULTRY MEAT
From these data, it is apparent that cooling of chickens in 10 or 20 ppm. chlorine water is an effective means of increasing shelf-life. Such a procedure could be followed in small processing plants which are not equipped with the inplant chlorination systems such as described by Miller (1953) and Goresline et al. (1951). The additional benefits of the inplant chlorination listed in the literature review should not be overlooked. The use of chlorine for a dip just prior to packaging did not appear to be a satisfactory means for increasing shelf-life
of poultry meat appreciably. SUMMARY
Ninety-six chicken fryers were used to check the effect of chlorine in the cooling water or in rinse water on shelf-life. All birds were split into halves so that paired comparisons between halves of the same chicken could be used for control and treated groups. It was found that chlorine used in the cooling water significantly increased shelflife as determined by off-odor or appearance of slime. The use of chlorine dip gave statistically significant difference in appearance of odor but no significant difference in appearance of slime. The differences were of such small magnitude to be of no practical importance. Use of chlorine cooling water had considerably more effect on shelf-life of birds processed at 128°F. than on those processed at 140°F. ACKNOWLEDGEMENTS
The chlorination equipment and measuring devices were supplied by Wallace and Tiernan, Inc., New York. REFERENCES Drewniak, E. E., M. A. Howe, Jr., H. E. Goresline and E. R. Baush, 1954. Studies on sanitizing methods for use in poultry processing. TJ.S.D.A. Cir. No. 930. Goresline, H. E., M. A. Howe, Jr., E. R. Bausch and M. F. Gunderson, 1951. Implant chlorination does three-way job. U. S. Egg and Poultry Mag. 57(4): 12-13, 29-31. Miller, M. W., 1953. Using inplant chlorination in chilled poultry operations. Fact Finding Conference Proceedings, Institute of American Poultry Industries, 1953: 95-98. Ziegler, F., J. V. Spencer and W. J. Stadelman, 1954. A rapid method for determining spoilage in fresh poultry meat. Poultry Sci. 33:1253-1255. Ziegler, F., and W. J. Stadelman, 1955. The effect of different scald water temperatures on shelflife of fresh, non-frozen fryers. Poultry Sci. 34: 237-238.
Downloaded from http://ps.oxfordjournals.org/ at University of Nebraka-Lincoln Libraries on April 13, 2015
The differences between 10 and 20 ppm. were not significant. In experiment 2, dipping the meat for 5 minutes in the treatment solutions, differences were much smaller than in experiment 1. These differences were statistically significant with respect to off-odor but not in respect to the appearance of slime. In experiment 3, the differences in days to spoilage were not so great as in experiment 1. However, these differences were still significant at the 1 percent level when analyzed statistically. The reduced effects of chlorine treatment in this experiment as compared with those in experiment 1 may be due to difference in temperature of the scald water used in the two experiments. The differences in shelf-life of the controls processed at 128°F. as compared with those processed at 140°F. were similar in magnitude to differences reported by Ziegler and Stadelman (1955). Much greater differences were noted in the halves that were chlorine-treated. This may be due to the fact that the lower temperature scald does not do so good a job of cleansing the surface as does the high temperature scald, the shorter shelflife of high temperature scald being due to greater vulnerability of the surface to bacterial growth.
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