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Experimental, Prototype Spray-Scalder for Poultry Processing1
METABOLISM AND NUTRITION Experimental, Prototype Spray-Scalder for Poultry Processing1 J. A. DICKENS USDA/ARS-Russell Research Center, P. O. Box 5677, Athens, Georgia 30613 (Received for publication February 17, 1989)
1990 Poultry Science 69:409-413 INTRODUCTION
Bacterial cross-contamination of broiler carcasses during commercial-processing operations has become a major concern within the poultry industry. Two primary areas of concern have traditionally been the scald tanks and the pickers (Van Schothorst et al., 1972). Most commercial processing plants in the United States and abroad are using community scald baths of hot water ranging from 50 C to 60 C, in which carcasses are immersed for 1.5 to 2.5 min. The operation of such scalders creates the possibility for carcass cross-contamination. Mulder et al., (1978) reported that when a carcass was artificially contaminated with a marker organism and was placed in a conventional immersion scalder, 230 subsequent carcasses were also contaminated with the marker organism. Various types of scalding have included the objective of decreasing the microbial load on the carcasses. Patrick et al. (1972) found that steam-scalded carcasses (53 C to 55 C for .5 min) had significantly lower total bacterial counts when sampled after scald and pick than did hot-water-scalded carcasses (55 C for 2 min). Kaufman et al. (1972) reported that the microbiological quality of carcasses tested after chilling was about the same for standard
Mention of companies or commercial products does not imply recommendation or endorsement by the author, or by the employing institution, to the exclusion of others not mentioned.
tank immersion-scalding and subatmospheric steam-scalding. Fecal material from the growout house attached to the feathers and feet of broilers can contaminate the immersion scald bath. The turbulent action of the scald water, needed to ensure penetration of the scald water to the skin, washes the fecal material from the carcass and, thus, creates a potential for crosscontamination in the scald bath (Shackelford, 1988). In the present study, a spray-scalder was designed with the overall objective of developing a scalding unit of the add-on type that could replace the present commercial systems in use, without requiring an overall modification to the scald-pick area of a plant as suggested by Amstad (1964) and Veerkamp (1974). An add-on, replacement system would be more economical (considering initial costs) and, therefore, would be implemented more easily by commercial poultry processors. MATERIALS AND METHODS
General Seven-week-old, commercially reared broilers of mixed sex were obtained from a local processing plant and were transported immediately to the pilot facilities for slaughter. All birds had been off feed from 10 to 14 h before slaughter and off water from 4 to 6 h. Each bird was stunned (50 V, AC, for 10 s), killed by severing the carotid artery and jugular vein, and allowed to bleed for 1.5 min. In the following
409
Downloaded from http://ps.oxfordjournals.org/ at UIC Library, Collections Development on May 5, 2015
ABSTRACT A spray unit was designed and developed for the purpose of spray-scalding broiler type chickens, which could replace the conventional method of immersion-scalding. The spray unit consisted of a double manifold that sprayed a mixture of steam and hot water onto the broiler carcasses. A mixing valve, pressure regulator, and nozzles of various sizes were tested to regulate the temperature, pressure, and coverage of the spray onto the carcass. The final results indicated that the spray-scalding system operating at 60 C produced feather-release values similar to those obtained by immersion for soft-scalding (52 C) and hardscalding (56 C) carcasses. (Key words: feather release, picking, spray-scalding, immersion-scalding, scalding temperature)
410
DICKENS
description of experimental procedures, each trial represents a different lot of birds obtained on a different day from the source. Preliminary Investigations In order to determine the effectiveness of spray-scalding, a preliminary experiment was designed in order to determine the subcutaneous temperatures for the immersion-scalded carcasses versus the spray-scalded carcasses. Subcutaneous temperatures were measured during the immersion-scalding of the carcasses at scalding temperatures of 52 and 56 C. Eight carcasses were used for both scalding temperatures; the subcutaneous temperature was monitored at four different locations on each carcass: the anterior of the right breast, the posterior of the left breast, the femoral feather tract just above the crural apterium, and the interscapular region of the back. Copper-constatan (ANSI symbol T) thermocouples were implanted immediately postmortem between the skin and muscle of each carcass at the four locations. Type "T" thermocouples were used because of the relatively low temperatures and the moisture involved. The skin was punctured at each location so the thermocouples could be inserted with the thermocouple tips placed 2.5 cm anterior to the
insertion point in order to minimize any effect from water penetration during scalding. The thermocouples were secured by fastening a nylon band around the carcass and were connected to a data logger2 programmed to scan each thermocouple every 5 s and to print out instantaneous, minimum, maximum, and average temperatures every 15 s. Only mean values were used. The carcasses were then shackled and were moved into the commercial, immersiontype scald tank where they remained submerged for 2 min; the subcutaneous temperatures were monitored and were recorded for the duration of the scalding. One carcass was used in each of the eight trials per temperature. Sixteen carcasses were used for the immersion-scalding portion of the study. Determinations of spray times at various spray temperatures were completed using a small cabinet with eight full-cone spray nozzles3. The carcasses were prepared and the temperatures were monitored, as previously described. Hot water and steam were mixed using a mixing valve4 to provide spray tempera-
3
Monitor Labs Inc., San Diego, CA. Spraying Systems Co., Wheaton, IL. Strahman Valve Co., Florham Park, NJ.
Downloaded from http://ps.oxfordjournals.org/ at UIC Library, Collections Development on May 5, 2015
FIGURE 1. Experimental spray manifold.
SPRAY SCALDING BACK S I D E N O Z Z L E PLACEMENT HOUZWTAL SMCWG SHACXEL U>C
r
0",
O1
oc
O'
3.1
oc Oc
o»
OE
o»
Ot
I,
— lia
— l:.* — 203 — 132J-
BACK SIDE NOZZLE PLACEMENT VQT1CM. VACDK
M O O . urc
12.' c
c
-o
r^
o-
HJ>
,
o
i-
Y
„.,
BREAST SIQC NQZZEL PLACEMENT VOtnCM. I HKLEWTAL IMCOC SMOCZL LDC
Or-
Qr
• u rrr «-
,r°.
— 203 — — 6.33
O
"1TTT"
SPOOSMS W M sac VIEV
FIGURE 2. Schematic of the experimental manifold, showing nozzle placements and types. A, 1/8 GG 6 SQ full jet; B, 1/4 P 3520 full jet; C, 1/8 GG 5 full jet/ D, 1/4 P 5010 flatjef.E, 1/4 GG 6.5 full jet/F, 1/4 P1510 flat jet/G, 1/4 GG 10SQ full jet; and H, 1/4 K 10 flat jet.
tures of 60 C, 64 C, and 68 C ± 1.5 C. Sixteen carcasses were evaluated. Experimental A double manifold was designed and installed in the pilot facility (diagonal, downsloping, 132 cm long with a 42-cm drop in elevation and initially equipped with eight equally spaced, full-cone nozzles per side). The
carcasses were passed through the manifold, and spray coverage was visually noted. Nozzles were added, and the nozzle type and placement were modified until the spray covered all portions of the carcass. Using the time-temperature results from the small cabinet, 16 carcasses (four replications of 4 carcasses each) with thermocouples in place were passed through the manifold. Line speed, nozzles, and nozzle direction were recorded when the desired subcutaneous temperature had been reached. Nozzle-direction changes were made using adjustable joints5. The effectiveness of the spray-scald was evaluated by measuring the feather-release values required to pull the feathers from their follicles, as described by Dickens and Shackelford (1988). One hundred and eight carcasses were scalded (18 each by immersion at 52 C and 56 C and by spraying at 60 C), the mature feathers were pulled from the pectoral tract, and the feather-release values were recorded. This procedure was then replicated. The prototype spray-scald manifold tested after final modifications (Figures 1 and 2) was 132 cm long with a maximum drop in elevation of 53 cm. The distance between the back-side manifold and the breast-side manifold was 36 cm. Figure 2 shows a side view of the sprayscalder nozzle positions. There were two manifolds connected to a central supply of steam and hot water, one to the back of the carcass and the other to the breast side. The manifold to the back of the carcass had 11 nozzles; the manifold to the breast side had only 6 nozzles. The nozzles were all of the full-cone or flat-spray type. (The sizes are specified in the legend for Figure 2.) The flow rate of the steam-hot water mix at 137.9 kPa was calculated from the nozzle-specification guide furnished by the manufacturer. The calculated flow rate at 137.9 kPa was 6 L per carcass. Statistical Analysis The temperature data were the means of the four thermocouples and eight carcasses used for each temperature setting. All feather-release data are reported as the means of six feathers per carcass. The data were analyzed by ANOVA, using the general linear model procedures of the
5
Spraying Systems Co., Wheaton, IL.
Downloaded from http://ps.oxfordjournals.org/ at UIC Library, Collections Development on May 5, 2015
— 7i
411
412
DICKENS
Statistical Analysis System (SAS Institute, 1985). The main effects for the feather-release values were by method of scalding (immersion and spray). Significant differences between the means were calculated, using the standard t test for least significance. RESULTS AND DISCUSSION
Preliminary
Experimental In an effort to simulate immersion-scalding results, the subcutaneous temperature of 50 C was used to extrapolate the approximate spray time that would be required. As given in Figure 3, the time required for the 60 C spray temperature was .5 min.
TABLE 1. Feather-release values1, for immersionscalded and spray-scalded carcasses (± SD) 52 C, 2-min immersion Replication scald 150a 132a 141a ± 17
1 2 X a
56 C, 2-min immersion scald
60 C, 30-s spray scald
(g) 86 b 90 b 88 b ± 12
102" 94 b 98 b ± 17
' Values in the same row with no common superscripts are significantly different (P<.05). n = 18 carcasses per replication, for 108 total. Each value represents six feathers per carcass.
45
60
75
90
105
120
135
TIME ( s e c o n d s )
FIGURE 3. Subcutaneous temperatures (Temp) at various scald temperatures for broiler carcasses using spray or immersion (imm.) scalding.
Downloaded from http://ps.oxfordjournals.org/ at UIC Library, Collections Development on May 5, 2015
Mean subcutaneous temperatures for all immersion and spray-scalded carcasses were plotted against time (Figure 3). The standard deviation of the temperatures calculated for location and time were less than 1 C; therefore, the means for all four thermocouples were used. The mean subcutaneous temperatures for immersion-scalding for the 2-min scald time at 52 C and 56 C were 49.3 C and 51.9 C, respectively. These values approximate those reported by Dickens and Shackelford (1988) of 48.8 C and 51.6 C for the same scald-time and respective temperatures. Spray-scalding at temperatures at 64 C and 68 C affected the skin to the point that it tore easily. The spray at 60 C showed no evidence that the skin was affected; and no tearing was observed. Therefore, the spray-scald at 60 C was the focus of the remaining trials.
The feamer-release values (Table 1) for immersion-scalding at 52 C and 56 C were 141 g and 88 g, respectively. These values are comparable to those of 133 g and 90 g, respectively, for the same scalding times and temperatures as reported by Dickens and Shackelford (1988). In the present study, the carcasses sprayscalded at 60 C for .5 min had a mean featherrelease value of 98 g, which was intermediate for the values of the 2-min immersion scald of 52 C and 56 C. The immersion-scald treatment at 52 C resulted in significantly higher feather-release values (P<.05) than either the immersion-scald at 56 C or the spray-scald (Table 1). There were no significant differences between the 56-C treatment and the spray-scald treatments. Based on feather-release values necessary to pull feathers after scalding, the prototype sprayscalder created for the present investigation represents a viable alternative to standard immersion-scalding at 56 C for 2 min. Implementation of such a system could reduce the fecal and microbiological cross-contamination now occurring in immersion-scalders. Commercial broiler processing plants in die Southeast United States use immersion-scalding times ranging from 2 to 2.5 min. In the present study, an immersion-scalding time of 2 min was used to evaluate the spray-scalder. Dickens and Shackelford (1988) demonstrated that featherrelease values increased by 12% when the time in the scalder at 52 C was increased from 2 min to 2.5 min. Knapp and Newell (1961) showed a similar increase (16%) when the time in the
SPRAY SCALDING
immersion-scald at 57 C was increased by 45 s. Therefore, the 2-min scald time was used to compare feather-release values for immersion and spray-scalded carcasses. ACKNOWLEDGMENTS
The author thanks R. Vaughn and J. Adams for their technical assistance and E. Hawkins and R. Chandler for their excellent clerical work.
Amstad, J. H., 1964. Poultry Processing Methods and Apparatus. U.S. Patent 3,138,822. 1964 June 30. 7 p. Int. CL. 17-112. Dickens, J. A., and A. D. Shackelford, 1988. Feather release forces as related to stunning, scald time and scald temperature. Poultry Sci. 67:1069-1074. Kaufman, V. F., A. A. Klosc, H. G. Bayne, M. F. Pool, and H. Lineweaver, 1972. Plant processing of sub-atmo-
spheric steam scalded poultry. Poultry Sci. 51: 1188-1194. Knapp, B. G., and G. W. Newell, 1961. Effect of selected factors on feather removal in chickens. Poultry Sci. 40: 510-517. Mulder, R.W.A.W., L.W.J. Dorresteijn, and J. van der Borek, 1978. Cross-contaminauon during the scalding and picking of broilers. Br. Poult. Sci. 19:61-70. Patrick, T. E., T. L. Goodwin, J. A. Collins, R. C. Wyche, and B. E. Love, 1972. Steam versus hot-water scalding in reducing bacterial loads on the skin of commercially processed poultry. Appl. Microbiol. 23:796-798. SAS Institute, 1985. SAS User's Guide: Statistics, Version 5 Edition. SAS Inst. Inc., Cary, NC. Shackelford, A. D., 1988. Modifications of processing methods to control Salmonella in poultry. Poultry Sci. 67: 933-935. Van Schothorst, M., S. Notermans, and E. H. Kampelmacher, 1972. Einigne hygienische Aspekte der Geflugeischlachtung. Fleischwirtschaft 52:749-752. Veerkamp, C. H., 1974. The simultaneous scalding and picking of broiler carcasses compared with an industrial method of processing. Pages 450-451 in: Proc. 15th World Poult. Congr., New Orleans, LA.
Downloaded from http://ps.oxfordjournals.org/ at UIC Library, Collections Development on May 5, 2015
REFERENCES
413
1990 Poultry Science 69:409-413 INTRODUCTION
Bacterial cross-contamination of broiler carcasses during commercial-processing operations has become a major concern within the poultry industry. Two primary areas of concern have traditionally been the scald tanks and the pickers (Van Schothorst et al., 1972). Most commercial processing plants in the United States and abroad are using community scald baths of hot water ranging from 50 C to 60 C, in which carcasses are immersed for 1.5 to 2.5 min. The operation of such scalders creates the possibility for carcass cross-contamination. Mulder et al., (1978) reported that when a carcass was artificially contaminated with a marker organism and was placed in a conventional immersion scalder, 230 subsequent carcasses were also contaminated with the marker organism. Various types of scalding have included the objective of decreasing the microbial load on the carcasses. Patrick et al. (1972) found that steam-scalded carcasses (53 C to 55 C for .5 min) had significantly lower total bacterial counts when sampled after scald and pick than did hot-water-scalded carcasses (55 C for 2 min). Kaufman et al. (1972) reported that the microbiological quality of carcasses tested after chilling was about the same for standard
Mention of companies or commercial products does not imply recommendation or endorsement by the author, or by the employing institution, to the exclusion of others not mentioned.
tank immersion-scalding and subatmospheric steam-scalding. Fecal material from the growout house attached to the feathers and feet of broilers can contaminate the immersion scald bath. The turbulent action of the scald water, needed to ensure penetration of the scald water to the skin, washes the fecal material from the carcass and, thus, creates a potential for crosscontamination in the scald bath (Shackelford, 1988). In the present study, a spray-scalder was designed with the overall objective of developing a scalding unit of the add-on type that could replace the present commercial systems in use, without requiring an overall modification to the scald-pick area of a plant as suggested by Amstad (1964) and Veerkamp (1974). An add-on, replacement system would be more economical (considering initial costs) and, therefore, would be implemented more easily by commercial poultry processors. MATERIALS AND METHODS
General Seven-week-old, commercially reared broilers of mixed sex were obtained from a local processing plant and were transported immediately to the pilot facilities for slaughter. All birds had been off feed from 10 to 14 h before slaughter and off water from 4 to 6 h. Each bird was stunned (50 V, AC, for 10 s), killed by severing the carotid artery and jugular vein, and allowed to bleed for 1.5 min. In the following
409
Downloaded from http://ps.oxfordjournals.org/ at UIC Library, Collections Development on May 5, 2015
ABSTRACT A spray unit was designed and developed for the purpose of spray-scalding broiler type chickens, which could replace the conventional method of immersion-scalding. The spray unit consisted of a double manifold that sprayed a mixture of steam and hot water onto the broiler carcasses. A mixing valve, pressure regulator, and nozzles of various sizes were tested to regulate the temperature, pressure, and coverage of the spray onto the carcass. The final results indicated that the spray-scalding system operating at 60 C produced feather-release values similar to those obtained by immersion for soft-scalding (52 C) and hardscalding (56 C) carcasses. (Key words: feather release, picking, spray-scalding, immersion-scalding, scalding temperature)
410
DICKENS
description of experimental procedures, each trial represents a different lot of birds obtained on a different day from the source. Preliminary Investigations In order to determine the effectiveness of spray-scalding, a preliminary experiment was designed in order to determine the subcutaneous temperatures for the immersion-scalded carcasses versus the spray-scalded carcasses. Subcutaneous temperatures were measured during the immersion-scalding of the carcasses at scalding temperatures of 52 and 56 C. Eight carcasses were used for both scalding temperatures; the subcutaneous temperature was monitored at four different locations on each carcass: the anterior of the right breast, the posterior of the left breast, the femoral feather tract just above the crural apterium, and the interscapular region of the back. Copper-constatan (ANSI symbol T) thermocouples were implanted immediately postmortem between the skin and muscle of each carcass at the four locations. Type "T" thermocouples were used because of the relatively low temperatures and the moisture involved. The skin was punctured at each location so the thermocouples could be inserted with the thermocouple tips placed 2.5 cm anterior to the
insertion point in order to minimize any effect from water penetration during scalding. The thermocouples were secured by fastening a nylon band around the carcass and were connected to a data logger2 programmed to scan each thermocouple every 5 s and to print out instantaneous, minimum, maximum, and average temperatures every 15 s. Only mean values were used. The carcasses were then shackled and were moved into the commercial, immersiontype scald tank where they remained submerged for 2 min; the subcutaneous temperatures were monitored and were recorded for the duration of the scalding. One carcass was used in each of the eight trials per temperature. Sixteen carcasses were used for the immersion-scalding portion of the study. Determinations of spray times at various spray temperatures were completed using a small cabinet with eight full-cone spray nozzles3. The carcasses were prepared and the temperatures were monitored, as previously described. Hot water and steam were mixed using a mixing valve4 to provide spray tempera-
3
Monitor Labs Inc., San Diego, CA. Spraying Systems Co., Wheaton, IL. Strahman Valve Co., Florham Park, NJ.
Downloaded from http://ps.oxfordjournals.org/ at UIC Library, Collections Development on May 5, 2015
FIGURE 1. Experimental spray manifold.
SPRAY SCALDING BACK S I D E N O Z Z L E PLACEMENT HOUZWTAL SMCWG SHACXEL U>C
r
0",
O1
oc
O'
3.1
oc Oc
o»
OE
o»
Ot
I,
— lia
— l:.* — 203 — 132J-
BACK SIDE NOZZLE PLACEMENT VQT1CM. VACDK
M O O . urc
12.' c
c
-o
r^
o-
HJ>
,
o
i-
Y
„.,
BREAST SIQC NQZZEL PLACEMENT VOtnCM. I HKLEWTAL IMCOC SMOCZL LDC
Or-
Qr
• u rrr «-
,r°.
— 203 — — 6.33
O
"1TTT"
SPOOSMS W M sac VIEV
FIGURE 2. Schematic of the experimental manifold, showing nozzle placements and types. A, 1/8 GG 6 SQ full jet; B, 1/4 P 3520 full jet; C, 1/8 GG 5 full jet/ D, 1/4 P 5010 flatjef.E, 1/4 GG 6.5 full jet/F, 1/4 P1510 flat jet/G, 1/4 GG 10SQ full jet; and H, 1/4 K 10 flat jet.
tures of 60 C, 64 C, and 68 C ± 1.5 C. Sixteen carcasses were evaluated. Experimental A double manifold was designed and installed in the pilot facility (diagonal, downsloping, 132 cm long with a 42-cm drop in elevation and initially equipped with eight equally spaced, full-cone nozzles per side). The
carcasses were passed through the manifold, and spray coverage was visually noted. Nozzles were added, and the nozzle type and placement were modified until the spray covered all portions of the carcass. Using the time-temperature results from the small cabinet, 16 carcasses (four replications of 4 carcasses each) with thermocouples in place were passed through the manifold. Line speed, nozzles, and nozzle direction were recorded when the desired subcutaneous temperature had been reached. Nozzle-direction changes were made using adjustable joints5. The effectiveness of the spray-scald was evaluated by measuring the feather-release values required to pull the feathers from their follicles, as described by Dickens and Shackelford (1988). One hundred and eight carcasses were scalded (18 each by immersion at 52 C and 56 C and by spraying at 60 C), the mature feathers were pulled from the pectoral tract, and the feather-release values were recorded. This procedure was then replicated. The prototype spray-scald manifold tested after final modifications (Figures 1 and 2) was 132 cm long with a maximum drop in elevation of 53 cm. The distance between the back-side manifold and the breast-side manifold was 36 cm. Figure 2 shows a side view of the sprayscalder nozzle positions. There were two manifolds connected to a central supply of steam and hot water, one to the back of the carcass and the other to the breast side. The manifold to the back of the carcass had 11 nozzles; the manifold to the breast side had only 6 nozzles. The nozzles were all of the full-cone or flat-spray type. (The sizes are specified in the legend for Figure 2.) The flow rate of the steam-hot water mix at 137.9 kPa was calculated from the nozzle-specification guide furnished by the manufacturer. The calculated flow rate at 137.9 kPa was 6 L per carcass. Statistical Analysis The temperature data were the means of the four thermocouples and eight carcasses used for each temperature setting. All feather-release data are reported as the means of six feathers per carcass. The data were analyzed by ANOVA, using the general linear model procedures of the
5
Spraying Systems Co., Wheaton, IL.
Downloaded from http://ps.oxfordjournals.org/ at UIC Library, Collections Development on May 5, 2015
— 7i
411
412
DICKENS
Statistical Analysis System (SAS Institute, 1985). The main effects for the feather-release values were by method of scalding (immersion and spray). Significant differences between the means were calculated, using the standard t test for least significance. RESULTS AND DISCUSSION
Preliminary
Experimental In an effort to simulate immersion-scalding results, the subcutaneous temperature of 50 C was used to extrapolate the approximate spray time that would be required. As given in Figure 3, the time required for the 60 C spray temperature was .5 min.
TABLE 1. Feather-release values1, for immersionscalded and spray-scalded carcasses (± SD) 52 C, 2-min immersion Replication scald 150a 132a 141a ± 17
1 2 X a
56 C, 2-min immersion scald
60 C, 30-s spray scald
(g) 86 b 90 b 88 b ± 12
102" 94 b 98 b ± 17
' Values in the same row with no common superscripts are significantly different (P<.05). n = 18 carcasses per replication, for 108 total. Each value represents six feathers per carcass.
45
60
75
90
105
120
135
TIME ( s e c o n d s )
FIGURE 3. Subcutaneous temperatures (Temp) at various scald temperatures for broiler carcasses using spray or immersion (imm.) scalding.
Downloaded from http://ps.oxfordjournals.org/ at UIC Library, Collections Development on May 5, 2015
Mean subcutaneous temperatures for all immersion and spray-scalded carcasses were plotted against time (Figure 3). The standard deviation of the temperatures calculated for location and time were less than 1 C; therefore, the means for all four thermocouples were used. The mean subcutaneous temperatures for immersion-scalding for the 2-min scald time at 52 C and 56 C were 49.3 C and 51.9 C, respectively. These values approximate those reported by Dickens and Shackelford (1988) of 48.8 C and 51.6 C for the same scald-time and respective temperatures. Spray-scalding at temperatures at 64 C and 68 C affected the skin to the point that it tore easily. The spray at 60 C showed no evidence that the skin was affected; and no tearing was observed. Therefore, the spray-scald at 60 C was the focus of the remaining trials.
The feamer-release values (Table 1) for immersion-scalding at 52 C and 56 C were 141 g and 88 g, respectively. These values are comparable to those of 133 g and 90 g, respectively, for the same scalding times and temperatures as reported by Dickens and Shackelford (1988). In the present study, the carcasses sprayscalded at 60 C for .5 min had a mean featherrelease value of 98 g, which was intermediate for the values of the 2-min immersion scald of 52 C and 56 C. The immersion-scald treatment at 52 C resulted in significantly higher feather-release values (P<.05) than either the immersion-scald at 56 C or the spray-scald (Table 1). There were no significant differences between the 56-C treatment and the spray-scald treatments. Based on feather-release values necessary to pull feathers after scalding, the prototype sprayscalder created for the present investigation represents a viable alternative to standard immersion-scalding at 56 C for 2 min. Implementation of such a system could reduce the fecal and microbiological cross-contamination now occurring in immersion-scalders. Commercial broiler processing plants in die Southeast United States use immersion-scalding times ranging from 2 to 2.5 min. In the present study, an immersion-scalding time of 2 min was used to evaluate the spray-scalder. Dickens and Shackelford (1988) demonstrated that featherrelease values increased by 12% when the time in the scalder at 52 C was increased from 2 min to 2.5 min. Knapp and Newell (1961) showed a similar increase (16%) when the time in the
SPRAY SCALDING
immersion-scald at 57 C was increased by 45 s. Therefore, the 2-min scald time was used to compare feather-release values for immersion and spray-scalded carcasses. ACKNOWLEDGMENTS
The author thanks R. Vaughn and J. Adams for their technical assistance and E. Hawkins and R. Chandler for their excellent clerical work.
Amstad, J. H., 1964. Poultry Processing Methods and Apparatus. U.S. Patent 3,138,822. 1964 June 30. 7 p. Int. CL. 17-112. Dickens, J. A., and A. D. Shackelford, 1988. Feather release forces as related to stunning, scald time and scald temperature. Poultry Sci. 67:1069-1074. Kaufman, V. F., A. A. Klosc, H. G. Bayne, M. F. Pool, and H. Lineweaver, 1972. Plant processing of sub-atmo-
spheric steam scalded poultry. Poultry Sci. 51: 1188-1194. Knapp, B. G., and G. W. Newell, 1961. Effect of selected factors on feather removal in chickens. Poultry Sci. 40: 510-517. Mulder, R.W.A.W., L.W.J. Dorresteijn, and J. van der Borek, 1978. Cross-contaminauon during the scalding and picking of broilers. Br. Poult. Sci. 19:61-70. Patrick, T. E., T. L. Goodwin, J. A. Collins, R. C. Wyche, and B. E. Love, 1972. Steam versus hot-water scalding in reducing bacterial loads on the skin of commercially processed poultry. Appl. Microbiol. 23:796-798. SAS Institute, 1985. SAS User's Guide: Statistics, Version 5 Edition. SAS Inst. Inc., Cary, NC. Shackelford, A. D., 1988. Modifications of processing methods to control Salmonella in poultry. Poultry Sci. 67: 933-935. Van Schothorst, M., S. Notermans, and E. H. Kampelmacher, 1972. Einigne hygienische Aspekte der Geflugeischlachtung. Fleischwirtschaft 52:749-752. Veerkamp, C. H., 1974. The simultaneous scalding and picking of broiler carcasses compared with an industrial method of processing. Pages 450-451 in: Proc. 15th World Poult. Congr., New Orleans, LA.
Downloaded from http://ps.oxfordjournals.org/ at UIC Library, Collections Development on May 5, 2015
REFERENCES
413