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Use of Radioactive 36Cl to Determine Distribution of Chloride in Poultry Meat Exposed to Chlorinated Chillwater*
Use of Radioactive 3 6 CI to Determine Distribution of Chloride in Poultry Meat Exposed to Chlorinated ChiUwater* M. G. MAST, R. D. MCCARTHY and B. Q. PHILLIPPY Department of Food Science, The Pennsylvania State University, University Park, Pennsylvania 16802 (Received for publication April 11, 1977)
Poultry Science 56:2022-2025, 1977
INTRODUCTION Chlorine c o m p o u n d s have been utilized as anti-microbial agents in p o u l t r y plants for m a n y years. Since chlorine has excellent sanitizing qualities the United States D e p a r t m e n t of Agriculture (U.S.D.A., 1968) has p e r m i t t e d chlorine to be a d d e d t o t h e p o t a b l e water system in processing plants u p t o 2 0 p . p . m . , in h a n d rinses u p t o 5 0 p.p.m., and in sanitizing rinses u p t o 2 0 0 p . p . m . Chlorine in c o n t i n u o u s chilling systems can be effective in reducing bacterial n u m b e r s . T o achieve desired reductions, t h e residual chlorine in the water a n d t h e a m o u n t of water per carcass m u s t be closely m o n i t o r e d . Several workers (Mead and T h o m a s , 1 9 7 3 ; Blood and Jarvis, 1974) have r e p o r t e d t h a t m a x i m u m benefits from chlorination are o b t a i n e d when large volumes of water are c o m b i n e d with high residual total chlorine (30—50 p . p . m . ) . Higher bacterial n u m b e r s were observed w h e n water usage was reduced or w h e n t h e residual chlorine was low. N u m e r o u s additional studies o n con-
* Authorized for publication on March 31, 1977 as paper no. 5276 in the journal series of The Pennsylvania Agricultural Experiment Station.
t i n u o u s chilling and chlorination are reviewed by T h o m p s o n et al. ( 1 9 7 4 ) . Although chlorine is p e r m i t t e d b y U.S.D.A. t o c o m e in c o n t a c t with p o u l t r y , it never received " p r i o r s a n c t i o n " for use by t h e F o o d and Drug A d m i n i s t r a t i o n and is therefore n o t a G R A S (Generally Recognized As Safe) substance. C u r r e n t concerns regarding chlorine pertain t o t h e legality (as m e n t i o n e d above) and safety of using it in c o n t a c t with foods. T h e safety of exposing foods t o chlorinated water has recently been questioned since it has been d e m o n s t r a t e d t h a t chlorination of municipal wastewaters can increase t h e toxicity of t h e effluent t o a q u a t i c life (Brungs, 1 9 7 3 ; Esvelt et al., 1973). Chlorination of wastewaters has resulted in t h e formation of a variety of chlorinated c o m p o u n d s , including chloramines (Brungs, 1 9 7 3 ) . When p o u l t r y , or other organic m a t t e r , comes in c o n t a c t with chlorinated chiUwater t h e residual chlorine in t h e water is lowered. A t the present t i m e little is k n o w n regarding t h e fate of t h e chlorine. Some obviously dissipates into t h e air and s o m e m a y be incorporated i n t o organic or inorganic c o m p o u n d s . T h e purpose of t h e present s t u d y is t o d e t e r m i n e t h e distribution and n a t u r e of chloride in p o u l t r y
2022
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ABSTRACT Chlorine has been used to control microbial levels in poultry chiUwater systems for many years. Recendy, however, concern has arisen regarding the fate of organic compounds when exposed to chlorinated water supplies. The present study was designed to determine the distribution and nature of chloride in poultry tissues exposed to chiUwater containing radioactive 36 CI. Breasts from freshly slaughtered chickens were chilled for 3 min., 1 hr., or 24 hr. in water containing 50 p.p.m. of chlorine. Raw and cooked portions of skin and muscle were then assayed for radioactivity. Skin portions consistendy contained higher levels of radioactivity than muscle. For example, skin exposed to chlorinated chiUwater for 1 hr. contained 21.8 p.p.m., whereas muscle tissues contained 4.4 p.p.m. The concentration of 3 6 CI in tissues increased as exposure time to the chlorinated chiUwater increased. Cooking chlorinated tissues generally reduced the concentration of chloride in skin and increased the concentration in muscle. Tests conducted to define the nature of "added" chloride in the tissue indicate that it is probably present as an inorganic salt and not as organochlorine compounds.
CARCASS CHLORIDE FROM CHILLWATER tissues exposed to chillwater containing radioactive 3 6 Cl. METHODS AND MATERIALS
conducted to simulate cooking and chilling procedures used in some poultry plants engaged in further processing. Tests were conducted 3 times. Experiment 3. Several tests were conducted in an effort to further characterize the chemical form of the 3 6 C1 remaining in the tissues exposed to chlorinated chillwater. Tests were designed to determine approximate molecular size of compounds containing 3 6 Cl, whether these compounds were organic or inorganic in nature, and whether they were present in aqueous or lipid phases. Samples of chlorinated chicken tissues were cut-up, placed into water, and sonicated. The subsequent slurries were dialyzed for 20 hr. against distilled water using the dialysis tubing with an average pore diameter of 4.8 n.m. which permits passage of molecules not exceeding 12,000 in molecular weight. The dialysate was then freeze-dried and ashed at 525 C. for 2 hr. Additional samples of tissue were finely ground and then extracted with ethanol, petroleum ether, and ethyl ether. RESULTS AND DISCUSSION The results of experiment 1 are shown in Table 1. The skin portion consistently contained the highest concentration of radioactivity, followed by the superficial pectoral muscles, and finally the deep pectoral muscles. In addition, the concentration of 3 6 C1 in tissues increased as exposure time to the chlorinated chillwater increased. Proposed regulations indicate that poultry may be emersed in chlorinated chillwater no longer than 20 min. per pound of carcass; therefore, a 3-pound chicken could be in emersion for up to 1 hr. As seen in Table 1, the chloride in breast muscle increased 4—5 p.p.m. in a 1 hr. period. The chicken used in this study may also be exhibiting greater increases in chloride uptake since "cut-up" breasts were used, thereby exposing more breast tissue to the chillwater than if whole birds were used. Chicken skin which had been cooked for 45 min. at 163°C. had approximately one-third less chloride than comparable raw skin (Table 1). However, the chloride concentration increased about 25% in the superficial pectoral and about 50% in the deep pectoral muscles. Results of experiment 2 (Table 2), in which cooked breasts were exposed to chlorinated
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Breasts from freshly slaughtered, non-chilled chicken were used in this study. Within 15 min. after slaughter these breasts were weighed and placed into chillwater (<5 C.) containing 50 p.p.m. chlorine, prepared by adding 3.96 ml. of the liquid sanitizer Klenzade XY-12 (Klenzade Products, St. Paul, MN) to 2000 ml. of tap water. Ten //Ci of H 3 6 C1 were added as a radioactive tracer. After exposure to the chlorinated chillwater, the breasts were rinsed in running tap water for 15 sec. The following portions of tissue were removed for analyses: 1) skin, 2) superficial pectoral muscles (pectoralis superficialis), and 3) deep pectoral muscles (pectoralis profundus). Tissue samples were finely ground in a Bowland-Jacobs Food Grinder. Subsequently, 100—200 mg. of the ground tissue were digested in scintillation vials by adding 2 ml. of Soluene (tissue solubilizer) and incubating at 40 C. Following solubilization, 10 ml. of Scintill AR scintillation fluid were added and radioactivity measured in a Packard Tri-Carb liquid scintillation spectrometer. The specific activity of Cl (c.p.m./jii.g.) in the chillwater bath was determined for each experiment. This value made it possible to calculate the total amount of chloride transferred to the tissues. Results are expressed as p.p.m. It was assumed that the Cl in the radioactive and nonradioactive compounds migrated from the chillwater into the chicken tissues in a similar manner. Experiment I. Three chicken breasts were held in chlorinated chillwater (50 p.p.m.) for 3 min., 1 hr., or 24 hr., after which they were removed, rinsed with water, drained, and split in half. Tissues from one-half were examined for radioactivity; the second half was cooked at 163 C. for 45 min. before assaying for radioactivity. Juices from the cooked portion were also collected and analyzed. This study was conducted 3 times. Experiment 2. This series of tests was conducted in a similar manner to experiment 1 except for the following: 1) breast portions were first cooked in water (80 C. for 30 min.) to an internal temperature of 71 C , and 2) cooked breasts were held in chlorinated chillwater for either 1 min. or 1 hr. These tests were
2023
M. G. MAST, R. D. MCCARTHY AND B. a PHILLIPPY
2024
TABLE 1 .—Concentration of CI in raw and cooked poultry tissues obtained upon exposure of raw poultry to chlorinated chillwater3Raw CI, p.p.m.
Cooked CI, p.p.m.
Skin
3 min. lhr. 24 hr.
13.8 ± 1.0b 21.8 ± 1.5 47.3 ± 9.0
9.0 ± 1.5 15.5 ± 1.3 31.6 ± 3.9
Superficial pectoral
3 min. 1 hr. 24 hr.
2.5 ±0.3 4.4 ±1.0 21.7 ± 3.8
3.6 ±0.5 5.9 ± 0.6 26.3 ± 1.7
Deep pectoral
3 min. 1 hr. 24 hr.
0.8 ± 0.4 4.4 ± 1.6 10.6 ± 1.7
2.2 ± 0.7 5.4 ± 0.4 16.3 ± 3.5
Juice
3 min, 1 hr. 24 hr.
Chillwater contained 50 p.p.m. chlorine plus \0fiCi
6.7 ± 1.0 12.6 ±0.3 22.9 ± 2.0 36
C1.
Mean and standard error of the mean. Each value is the mean of three trials.
When the dialysate was freeze-dried and then heated at 525°C. for 2 hr., most of the radioactivity remained in the ash residue. The ash from skin contained 98.5%, the superficial pectoral 91.5%, and the deep pectoral 100% of the added radioactivity. These results suggest that 3 6 C1 is present an an inorganic salt. When poultry tissues exposed to CI were finely ground and then extracted with ethanol, petroleum ether, and ethyl ether, the results indicated no radioactivity in the lipid phase of the tissue. Since the juice from heated chicken
chillwater, were similar to experiment 1 in that the skin contained more radioactivity than muscle tissue, and 3 6 CI concentration increased with time. Cooked skin also did not "take-up" as much CI as uncooked skin when exposed for comparable periods of time. The results of chicken samples exposed to dialysis for 20 hr. are shown in Table 3. An excess of 90% of all the radioactivity was present in the dialysate indicating that the molecules containing the 3 6 C1 had a low molecular weight.
TABLE 2.—Concentration of CI in cooked and reheated poultry tissues obtained upon exposure of cooked poultry to chlorinated chillwater3Exposure time
Cooked CI, p.p.m.
Skin
1 min. 1 hr.
3.7 ± 0.4 b 13.2 ± 1.5
Superficial pectoral
1 min. 1 hr.
1.3 ±0.2 7.7 ±0.8
2. 1 ±0.4 10. 1 ±0.6
Deep pectoral
1 min. 1 hr.
2.3 ± 0.2 5.2 ± 0.8
2 ± 0.2 7 ±0.8
Juice
1 min. 1 hr.
Tissue
Chillwater contained 50 p.p.m. chlorine plus 10/iCi
Re heated CI, p.p.m. 5 ±0.2 8± 1.7
4. 3 ±0.5 16. 8 ± 0.9 36
C1.
Mean and standard error of the mean. Each value is the mean of three trials.
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Exposure time
Tissue
CARCASS CHLORIDE FROM CHILLWATER TABLE 3 .—Distribution of radioactivity in dialyzed poultry tissues % of CPM*
Tissue
Dialysate
Remaining in dialysis tube
Skin Superficial pectoral Deep pectoral
93.5 91.4 96.7
6.5 8.6 3.3
Expressed as a percentage of the total counts per minute (CPM) prior to dialysis.
1 Value of 400 p.p.m. in chicken muscle tissue is based on assumption that chicken muscle and human muscle have comparable chloride values. Human muscle tissue contains 40 mg./100 g. or 400 p.p.m. (Harper, 1969). Human plasma ( 9 7 - 1 0 8 mEq/L) and chicken plasma (109—120 mEq/L) have similar values (Altman, 1961).
chlorinated chillwater ( 5 0 p.p.m.) for 2 4 hr., an increase of a p p r o x i m a t e l y 25 p . p . m . in t h e muscle tissue m a y b e e x p e c t e d , i.e., 4 0 0 t o 4 2 5 p . p . m . or 6 . 2 5 % increase. T h e limited tests c o n d u c t e d in this s t u d y t o define t h e n a t u r e of this " a d d e d " chloride in t h e tissue indicate t h a t it is probably p r e s e n t as an inorganic salt and n o t as o r g a n o c h l o r i n e compounds. Therefore, t h e question remains if a 2.5% increase (1 hr. e x p o s u r e t o 5 0 p . p . m . C l 2 ) of chloride c o n t e n t (as an inorganic salt) is significant a n d / o r cause of concern.
REFERENCES Altman, P. L., 1961. Blood and Other Body Fluids. Federation of American Societies for Experimental Biology, Washington, DC, p. 186-187. Blood, R. M., and B. Jarvis, 1974. Chilling of poultry: the effects of process parameters on the level of bacteria in spin-chiller waters. J. Food Technol. 9:157-169. Brungs, W. A., 1973. Effects of residual chlorine on aquatic life. J. Water Pollution Control Fed. 45:2180-2195. Esvelt, L. A., W. J. Kaufman and R. E. Selleck, 1973. Toxicity assessment of treated municipal wastew a t e r s . J . Water Pollution Control Fed. 45:1558-1572. Harper, H. A., 1969. Review of Physiological Chemistry, 12th ed. Lange Medical Publications, Los Altos, CA, p. 435. Mead, G. C , and N. L. Thomas, 1973. Factors affecting thy use of chlorine in the spin-chilling of eviscerated poultry. Brit. Poultry Sci. 14:99—117. Thompson, J. E., W. K. Whitehead and A. J. Mercuri, 1974. Chilling Poultry Meat 2.—A literature review. Poultry Sci. 53:1268-1281. U.S.D.A., 1968. Poultry Inspector's Handbook, Consumer and Marketing Service, United States Department of Agriculture, Washington, DC 20250, p. 4.
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exhibited radioactivity (Tables 1 and 2), these samples were also separated i n t o lipid a n d a q u e o u s phases. Only t h e a q u e o u s phase contained radioactivity. As shown above, e x p o s u r e of p o u l t r y t o chlorinated chillwater does result in a slight increase in t h e a m o u n t of chloride p r e s e n t in p o u l t r y tissue. F o r example, p o u l t r y m e a t exposed for 1 hr. showed an increase of 4 t o 10 p . p . m . (Tables 1 a n d 2). Assuming chicken muscle normally contains a p p r o x i m a t e l y 4 0 0 p . p . m . of c h l o r i d e 1 , this represents an increase from 4 0 0 t o 4 1 0 p . p . m . in t h e tissue, or a p p r o x i m a t e l y 2.5%. If p o u l t r y is e x p o s e d t o
2025
Poultry Science 56:2022-2025, 1977
INTRODUCTION Chlorine c o m p o u n d s have been utilized as anti-microbial agents in p o u l t r y plants for m a n y years. Since chlorine has excellent sanitizing qualities the United States D e p a r t m e n t of Agriculture (U.S.D.A., 1968) has p e r m i t t e d chlorine to be a d d e d t o t h e p o t a b l e water system in processing plants u p t o 2 0 p . p . m . , in h a n d rinses u p t o 5 0 p.p.m., and in sanitizing rinses u p t o 2 0 0 p . p . m . Chlorine in c o n t i n u o u s chilling systems can be effective in reducing bacterial n u m b e r s . T o achieve desired reductions, t h e residual chlorine in the water a n d t h e a m o u n t of water per carcass m u s t be closely m o n i t o r e d . Several workers (Mead and T h o m a s , 1 9 7 3 ; Blood and Jarvis, 1974) have r e p o r t e d t h a t m a x i m u m benefits from chlorination are o b t a i n e d when large volumes of water are c o m b i n e d with high residual total chlorine (30—50 p . p . m . ) . Higher bacterial n u m b e r s were observed w h e n water usage was reduced or w h e n t h e residual chlorine was low. N u m e r o u s additional studies o n con-
* Authorized for publication on March 31, 1977 as paper no. 5276 in the journal series of The Pennsylvania Agricultural Experiment Station.
t i n u o u s chilling and chlorination are reviewed by T h o m p s o n et al. ( 1 9 7 4 ) . Although chlorine is p e r m i t t e d b y U.S.D.A. t o c o m e in c o n t a c t with p o u l t r y , it never received " p r i o r s a n c t i o n " for use by t h e F o o d and Drug A d m i n i s t r a t i o n and is therefore n o t a G R A S (Generally Recognized As Safe) substance. C u r r e n t concerns regarding chlorine pertain t o t h e legality (as m e n t i o n e d above) and safety of using it in c o n t a c t with foods. T h e safety of exposing foods t o chlorinated water has recently been questioned since it has been d e m o n s t r a t e d t h a t chlorination of municipal wastewaters can increase t h e toxicity of t h e effluent t o a q u a t i c life (Brungs, 1 9 7 3 ; Esvelt et al., 1973). Chlorination of wastewaters has resulted in t h e formation of a variety of chlorinated c o m p o u n d s , including chloramines (Brungs, 1 9 7 3 ) . When p o u l t r y , or other organic m a t t e r , comes in c o n t a c t with chlorinated chiUwater t h e residual chlorine in t h e water is lowered. A t the present t i m e little is k n o w n regarding t h e fate of t h e chlorine. Some obviously dissipates into t h e air and s o m e m a y be incorporated i n t o organic or inorganic c o m p o u n d s . T h e purpose of t h e present s t u d y is t o d e t e r m i n e t h e distribution and n a t u r e of chloride in p o u l t r y
2022
Downloaded from http://ps.oxfordjournals.org/ by guest on May 2, 2015
ABSTRACT Chlorine has been used to control microbial levels in poultry chiUwater systems for many years. Recendy, however, concern has arisen regarding the fate of organic compounds when exposed to chlorinated water supplies. The present study was designed to determine the distribution and nature of chloride in poultry tissues exposed to chiUwater containing radioactive 36 CI. Breasts from freshly slaughtered chickens were chilled for 3 min., 1 hr., or 24 hr. in water containing 50 p.p.m. of chlorine. Raw and cooked portions of skin and muscle were then assayed for radioactivity. Skin portions consistendy contained higher levels of radioactivity than muscle. For example, skin exposed to chlorinated chiUwater for 1 hr. contained 21.8 p.p.m., whereas muscle tissues contained 4.4 p.p.m. The concentration of 3 6 CI in tissues increased as exposure time to the chlorinated chiUwater increased. Cooking chlorinated tissues generally reduced the concentration of chloride in skin and increased the concentration in muscle. Tests conducted to define the nature of "added" chloride in the tissue indicate that it is probably present as an inorganic salt and not as organochlorine compounds.
CARCASS CHLORIDE FROM CHILLWATER tissues exposed to chillwater containing radioactive 3 6 Cl. METHODS AND MATERIALS
conducted to simulate cooking and chilling procedures used in some poultry plants engaged in further processing. Tests were conducted 3 times. Experiment 3. Several tests were conducted in an effort to further characterize the chemical form of the 3 6 C1 remaining in the tissues exposed to chlorinated chillwater. Tests were designed to determine approximate molecular size of compounds containing 3 6 Cl, whether these compounds were organic or inorganic in nature, and whether they were present in aqueous or lipid phases. Samples of chlorinated chicken tissues were cut-up, placed into water, and sonicated. The subsequent slurries were dialyzed for 20 hr. against distilled water using the dialysis tubing with an average pore diameter of 4.8 n.m. which permits passage of molecules not exceeding 12,000 in molecular weight. The dialysate was then freeze-dried and ashed at 525 C. for 2 hr. Additional samples of tissue were finely ground and then extracted with ethanol, petroleum ether, and ethyl ether. RESULTS AND DISCUSSION The results of experiment 1 are shown in Table 1. The skin portion consistently contained the highest concentration of radioactivity, followed by the superficial pectoral muscles, and finally the deep pectoral muscles. In addition, the concentration of 3 6 C1 in tissues increased as exposure time to the chlorinated chillwater increased. Proposed regulations indicate that poultry may be emersed in chlorinated chillwater no longer than 20 min. per pound of carcass; therefore, a 3-pound chicken could be in emersion for up to 1 hr. As seen in Table 1, the chloride in breast muscle increased 4—5 p.p.m. in a 1 hr. period. The chicken used in this study may also be exhibiting greater increases in chloride uptake since "cut-up" breasts were used, thereby exposing more breast tissue to the chillwater than if whole birds were used. Chicken skin which had been cooked for 45 min. at 163°C. had approximately one-third less chloride than comparable raw skin (Table 1). However, the chloride concentration increased about 25% in the superficial pectoral and about 50% in the deep pectoral muscles. Results of experiment 2 (Table 2), in which cooked breasts were exposed to chlorinated
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Breasts from freshly slaughtered, non-chilled chicken were used in this study. Within 15 min. after slaughter these breasts were weighed and placed into chillwater (<5 C.) containing 50 p.p.m. chlorine, prepared by adding 3.96 ml. of the liquid sanitizer Klenzade XY-12 (Klenzade Products, St. Paul, MN) to 2000 ml. of tap water. Ten //Ci of H 3 6 C1 were added as a radioactive tracer. After exposure to the chlorinated chillwater, the breasts were rinsed in running tap water for 15 sec. The following portions of tissue were removed for analyses: 1) skin, 2) superficial pectoral muscles (pectoralis superficialis), and 3) deep pectoral muscles (pectoralis profundus). Tissue samples were finely ground in a Bowland-Jacobs Food Grinder. Subsequently, 100—200 mg. of the ground tissue were digested in scintillation vials by adding 2 ml. of Soluene (tissue solubilizer) and incubating at 40 C. Following solubilization, 10 ml. of Scintill AR scintillation fluid were added and radioactivity measured in a Packard Tri-Carb liquid scintillation spectrometer. The specific activity of Cl (c.p.m./jii.g.) in the chillwater bath was determined for each experiment. This value made it possible to calculate the total amount of chloride transferred to the tissues. Results are expressed as p.p.m. It was assumed that the Cl in the radioactive and nonradioactive compounds migrated from the chillwater into the chicken tissues in a similar manner. Experiment I. Three chicken breasts were held in chlorinated chillwater (50 p.p.m.) for 3 min., 1 hr., or 24 hr., after which they were removed, rinsed with water, drained, and split in half. Tissues from one-half were examined for radioactivity; the second half was cooked at 163 C. for 45 min. before assaying for radioactivity. Juices from the cooked portion were also collected and analyzed. This study was conducted 3 times. Experiment 2. This series of tests was conducted in a similar manner to experiment 1 except for the following: 1) breast portions were first cooked in water (80 C. for 30 min.) to an internal temperature of 71 C , and 2) cooked breasts were held in chlorinated chillwater for either 1 min. or 1 hr. These tests were
2023
M. G. MAST, R. D. MCCARTHY AND B. a PHILLIPPY
2024
TABLE 1 .—Concentration of CI in raw and cooked poultry tissues obtained upon exposure of raw poultry to chlorinated chillwater3Raw CI, p.p.m.
Cooked CI, p.p.m.
Skin
3 min. lhr. 24 hr.
13.8 ± 1.0b 21.8 ± 1.5 47.3 ± 9.0
9.0 ± 1.5 15.5 ± 1.3 31.6 ± 3.9
Superficial pectoral
3 min. 1 hr. 24 hr.
2.5 ±0.3 4.4 ±1.0 21.7 ± 3.8
3.6 ±0.5 5.9 ± 0.6 26.3 ± 1.7
Deep pectoral
3 min. 1 hr. 24 hr.
0.8 ± 0.4 4.4 ± 1.6 10.6 ± 1.7
2.2 ± 0.7 5.4 ± 0.4 16.3 ± 3.5
Juice
3 min, 1 hr. 24 hr.
Chillwater contained 50 p.p.m. chlorine plus \0fiCi
6.7 ± 1.0 12.6 ±0.3 22.9 ± 2.0 36
C1.
Mean and standard error of the mean. Each value is the mean of three trials.
When the dialysate was freeze-dried and then heated at 525°C. for 2 hr., most of the radioactivity remained in the ash residue. The ash from skin contained 98.5%, the superficial pectoral 91.5%, and the deep pectoral 100% of the added radioactivity. These results suggest that 3 6 C1 is present an an inorganic salt. When poultry tissues exposed to CI were finely ground and then extracted with ethanol, petroleum ether, and ethyl ether, the results indicated no radioactivity in the lipid phase of the tissue. Since the juice from heated chicken
chillwater, were similar to experiment 1 in that the skin contained more radioactivity than muscle tissue, and 3 6 CI concentration increased with time. Cooked skin also did not "take-up" as much CI as uncooked skin when exposed for comparable periods of time. The results of chicken samples exposed to dialysis for 20 hr. are shown in Table 3. An excess of 90% of all the radioactivity was present in the dialysate indicating that the molecules containing the 3 6 C1 had a low molecular weight.
TABLE 2.—Concentration of CI in cooked and reheated poultry tissues obtained upon exposure of cooked poultry to chlorinated chillwater3Exposure time
Cooked CI, p.p.m.
Skin
1 min. 1 hr.
3.7 ± 0.4 b 13.2 ± 1.5
Superficial pectoral
1 min. 1 hr.
1.3 ±0.2 7.7 ±0.8
2. 1 ±0.4 10. 1 ±0.6
Deep pectoral
1 min. 1 hr.
2.3 ± 0.2 5.2 ± 0.8
2 ± 0.2 7 ±0.8
Juice
1 min. 1 hr.
Tissue
Chillwater contained 50 p.p.m. chlorine plus 10/iCi
Re heated CI, p.p.m. 5 ±0.2 8± 1.7
4. 3 ±0.5 16. 8 ± 0.9 36
C1.
Mean and standard error of the mean. Each value is the mean of three trials.
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Exposure time
Tissue
CARCASS CHLORIDE FROM CHILLWATER TABLE 3 .—Distribution of radioactivity in dialyzed poultry tissues % of CPM*
Tissue
Dialysate
Remaining in dialysis tube
Skin Superficial pectoral Deep pectoral
93.5 91.4 96.7
6.5 8.6 3.3
Expressed as a percentage of the total counts per minute (CPM) prior to dialysis.
1 Value of 400 p.p.m. in chicken muscle tissue is based on assumption that chicken muscle and human muscle have comparable chloride values. Human muscle tissue contains 40 mg./100 g. or 400 p.p.m. (Harper, 1969). Human plasma ( 9 7 - 1 0 8 mEq/L) and chicken plasma (109—120 mEq/L) have similar values (Altman, 1961).
chlorinated chillwater ( 5 0 p.p.m.) for 2 4 hr., an increase of a p p r o x i m a t e l y 25 p . p . m . in t h e muscle tissue m a y b e e x p e c t e d , i.e., 4 0 0 t o 4 2 5 p . p . m . or 6 . 2 5 % increase. T h e limited tests c o n d u c t e d in this s t u d y t o define t h e n a t u r e of this " a d d e d " chloride in t h e tissue indicate t h a t it is probably p r e s e n t as an inorganic salt and n o t as o r g a n o c h l o r i n e compounds. Therefore, t h e question remains if a 2.5% increase (1 hr. e x p o s u r e t o 5 0 p . p . m . C l 2 ) of chloride c o n t e n t (as an inorganic salt) is significant a n d / o r cause of concern.
REFERENCES Altman, P. L., 1961. Blood and Other Body Fluids. Federation of American Societies for Experimental Biology, Washington, DC, p. 186-187. Blood, R. M., and B. Jarvis, 1974. Chilling of poultry: the effects of process parameters on the level of bacteria in spin-chiller waters. J. Food Technol. 9:157-169. Brungs, W. A., 1973. Effects of residual chlorine on aquatic life. J. Water Pollution Control Fed. 45:2180-2195. Esvelt, L. A., W. J. Kaufman and R. E. Selleck, 1973. Toxicity assessment of treated municipal wastew a t e r s . J . Water Pollution Control Fed. 45:1558-1572. Harper, H. A., 1969. Review of Physiological Chemistry, 12th ed. Lange Medical Publications, Los Altos, CA, p. 435. Mead, G. C , and N. L. Thomas, 1973. Factors affecting thy use of chlorine in the spin-chilling of eviscerated poultry. Brit. Poultry Sci. 14:99—117. Thompson, J. E., W. K. Whitehead and A. J. Mercuri, 1974. Chilling Poultry Meat 2.—A literature review. Poultry Sci. 53:1268-1281. U.S.D.A., 1968. Poultry Inspector's Handbook, Consumer and Marketing Service, United States Department of Agriculture, Washington, DC 20250, p. 4.
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exhibited radioactivity (Tables 1 and 2), these samples were also separated i n t o lipid a n d a q u e o u s phases. Only t h e a q u e o u s phase contained radioactivity. As shown above, e x p o s u r e of p o u l t r y t o chlorinated chillwater does result in a slight increase in t h e a m o u n t of chloride p r e s e n t in p o u l t r y tissue. F o r example, p o u l t r y m e a t exposed for 1 hr. showed an increase of 4 t o 10 p . p . m . (Tables 1 a n d 2). Assuming chicken muscle normally contains a p p r o x i m a t e l y 4 0 0 p . p . m . of c h l o r i d e 1 , this represents an increase from 4 0 0 t o 4 1 0 p . p . m . in t h e tissue, or a p p r o x i m a t e l y 2.5%. If p o u l t r y is e x p o s e d t o
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