Alteration of Air Composition in Containers as a Result of the Extended Holding of Poultry Offal1

Alteration of Air Composition in Containers as a Result of the Extended Holding of Poultry Offal1

Alteration of Air Composition in Containers as a Result of the Extended Holding of Poultry Offal1 C. A. NEGBENEBOR, T. C. CHEN.2 and J. E. HILL Poultr...

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Alteration of Air Composition in Containers as a Result of the Extended Holding of Poultry Offal1 C. A. NEGBENEBOR, T. C. CHEN.2 and J. E. HILL Poultry Science Department, Mississippi State University, Mississippi State, Mississippi 39762 (Received for publication April 14, 1986)

1986 Poultry Science 65:2040-2042 INTRODUCTION be a nuisance to the environment as well as a In 1984, more than 4.28 billion broilers were possible health safety hazard to workers. The purpose of this study was to investigate slaughtered (Southeastern Poultry and Egg Association, 1986). This figure is expected to in- alterations of environmental air composition in crease in future years. Approximately 18.5% of a simulated offal container with and without the live weight of chicken is offal, which consists covers as a result of the extended holding of of head, feet, blood, feathers, viscera, and other poultry offal. inedible components. Poultry offal has high MATERIALS AND METHODS microbial loads and decomposes easily. During the microbial decomposition, various gases and Broiler offal in its normal composition ratio odorus components such as carbon dioxide, am- was obtained from an experimental poultry promonia, or sulfur-containing compounds may be cessing plant. Offal was placed in covered (C) produced. or open (O) 40-liter cylindrical containers with Offal is generally rendered as poultry offal a diameter of 20 cm and placed in field houses meal in poultry processing plants. In some oper- where the temperature was 21.0 C or cycled ations, offal is transported in trucks from the between 21.0 and 29.5 C. This cycled temperaprocessing plant to a central rendering location. ture represents hot summer environmental temIn this type of operation, some offal may be left peratures in Mississippi. The ratio of the poultry in the truck's holding tank overnight or over offal weight to container volume was approxiweekends. Due to high microbial loads, decom- mately 1:35 (w/v). position of offal in the holding tank, especially Holes of 1.24 cm in diameter were bored in during the hot summer season, could alter sur- the side of each container at 7.5, 22.5, and 37.5 rounding air composiiton. This alteration could cm from the bottom and plugged with rubber stoppers. Gas samples were drawn from these holes for analyses. Air near the center of the containers was sampled on Days 0, 2, 4, and 6 of holding. Carbon dioxide, hydrogen sulfide, 'Journal Paper Number 6462, Mississippi Agricultural and free ammonia contents were measured with and Forestry Experiment Station. 2 Matheson Kitagawa gas detector tubes (MatheTo whom correspondence should be addressed.

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ABSTRACT Broiler offal, in its normal composition ratio, was collected and placed in 20-cm diameter, cylindrical containers (40-liter) half covered and half uncovered. Containers were held at 21.0 C or in a field house at temperatures cycled from 21.0 to 29.5 C. The ratio of poultry offal weight to container volume was 1:35 (w/v). The air near the center of the containers was sampled and analyzed with various Kitagawa gas detector tubes and with an Orsat gas analysis apparatus after 0, 2, 4, and 6 days of holding. With the presence of offal, the oxygen in the containers decreased continuously as the holding time increased. After 4 days, the oxygen in the container held at 21.0 C decreased to 8.00 and 12.80% for those with and without lids; in hot summer (cycled 21.0 to 29.5 C) conditions, these oxygen values were 6.36 and 11.88%, respectively. Free ammonia in the covered containers increased from nondetectable to 232.0 and 310.8 ppm after 4 days of holding at 21.0 and in 21.0 to 29.5-cycled conditions, respectively. However, little or no free ammonia was detected from the containers without lids. An increase in hydrogen sulfide and carbon dioxide contents was also observed in the covered containers. Results suggested that the residues of offal in the transporting container could be a hazard for public safety during the hot summer season. (Key words: offal, air composition, holding tank)

EXTENDED HOLDING OF POULTRY OFFAL

son, East Rutherford, NJ). Percent oxygen was determined using an Orsat gas apparatus (Fisher Scientific, Lexington, MA). Experiments were repeated three times. Data was subjected to analysis of variance (Steel andTorrie, 1980). Duncan's (1955) multiple range and multiple F tests were used to analyze differences among the means. RESULTS AND DISCUSSION

No detectable carbon dioxide was found in open containers containing poultry offal (Tables 1 and 2). In covered containers, the amount of carbon dioxide in a 21.0 to 29.5 C cycled environment rose from nondetectable on Day 0 to 16.50% on Day 4. Generation of carbon dioxide was much slower at the lower temperature (Table 2). The average concentration of carbon dioxide in clean dry air is reported to be 313 to 318 ppm. Diurnal variations of 100 ppm in cities and a range of 300 to 500 ppm at various nonurban locations have been reported (Bibbero and Young, 1974). Carbon dioxide is considered a contaminant, not a pollutant, as harmful effects of current urban carbon dioxide concentrations have not yet been documented. At 21.0 C free ammonia increased from nondetectable to 110.0, 232.0, and 345.0 ppm respectively, after 2, 4, and 5 days of holding of residual poultry offal in covered containers (Table 2). The rate of free ammonia generation from offal was greater when the containers were in the 21.0 to 29.5 C cycled environment. In covered containers 310.8 ppm of free ammonia was recorded after 4 days of holding; this reading decreased slightly to 243.5 ppm on Day 6 (Table 1). Free ammonia has a density relative to air of .5967, which is lighter than air; no free ammonia was detected in the open containers. Animal wastes are the major source of ammonia pollution in the atmosphere (Anonymous, 1982). Background concentrations of free ammonia in the air are generally approximately .01 ppm. Ammonia is reported to be the most noxious abundant gas identified in the atmosphere of animal buildings (Lebeda, 1965; McAllister and

TABLE 1. Composition of air in covered (C) and open (O) containers containing residual poultry offal and stored in a 21.0 to 29.5 C cycled environment1 Carbon dioxide

Oxygen

Hydrogen sulfide

Ammonia

Holding (days)

(ppm)

(%) 9.87 a 4.10 b 6.36 c 5.51 d

0 2 4 6

19.88 a 15.30b 11.88 c 8.82 d

ND 2 13.58 c 16.50b 17.45 a

ND ND ND ND

ND 127.5 C 310.8 a 243.5 d

ND 16.3 a ND ND

a—d Means within each column with unlike letters differ significantly (P<.05). 1

Each reading is a mean of 12 observations.

2

ND = Nondetectable.

ND 175.0 a 175.0 a 136.4 b

ND 133.3 a 116.0 a 129.0 a

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No differences (P<.05) were found between air composition sample taken from 37.5, 22.5,and 7.5 cm from the bottom of the containers for both the opened and closed containers, although slightly higher free ammonia and slightly lower hydrogen sulfide concentrations were recorded from the closed containers. Therefore, data collected from the three sampling locations were pooled. Regardless of the holding temperature, poultry offal continuously decreased (P<.05) the oxygen concentrations of air in the containers (Tables 1 and 2). At the 21.0 to 29.5 C cycled daily temperature after 6 days of holding, oxygen concentration was reduced from 19.88 to 5.51 and 8.82% in the closed and opened containers, respectively. This decrease in oxygen content may be due to a biological decomposition process that consumes environmental oxygen. Normal atmosphere contains about 19 to 21% oxygen, and any environment contaning less than this is considered to be unsafe (Allison, 1979). Results suggest that residues of offal in transporting containers could be a hazard for public safety during the hot summer season.

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NEGBENEBOR ET AL. TABLE 2. Composition of air in covered (C) and open (O) containers containing residual poultry offal and stored at 21.0 C1 Carbon dioxide

Oxygen

Hydrogen sulfide

Free ammonia

Holding (days)

(ppm)

(%) 19.86 a 11.60 b 8.00 c 5.00 d

0 2 4 6

19.88 a 15.00° 12.80 c 5.00 d

ND 2 1.00a 1.36a 0.52 b

ND ND ND ND

ND 110.0 C 232.0 b 345.0 a

ND ND 10.0 ND

ND 25.0 b 75.0 a 37.0 b

ND ND ND ND

2

Each reading is a mean of 12 observations. ND = Nondetectable.

McQuitty, 1965). Inhalation of the concentrated vapor can cause edemas of the respiratory tract and spasms of the glottis (Stecher et al., 1968). In covered containers hydrogen sulfide content had a peak reading at Day 4 for both incubation conditions (Tables 1 and 2). In open containers a peak content of 133.3 ppm was obtained on Day 2 under 21.0 to 29.5 C-cycled hot summer conditions; no hydrogen sulfide was detected in the 21.0 C environment. Hydrogen sulfide composition in clean dry air is reported to be .2 ppm (Bibbero and Young, 1974). Hydrogen sulfide, with a density relative to air of 1.19, is heavier than air and thus stays in containers. Hydrogen sulfide is extremely hazardous and toxic to humans and may cause collapse, coma, and death from respiratory failure within a few seconds after inhalation (Stecher et al., 1986). Hydrogen sulfide is an insidious poison; it may cause fatigue of sense of smell and fail to give a warning of high concentrations that may lead to death within a few seconds. The rapid depletion of oxygen and production of hydrogen sulfide gases reported here may pose a potential health and safety hazard for poultry plant work-

ers, especially during hot summer weather, weekends, and holidays. Safety precautions should be made for those workers who are responsible for the cleaning and operation of poultry offal tanks. REFERENCES Allison, W. W., 1979. Hazard control of oxygen systems. Prof. Safety. October: 41-44. Anonymous, 1982. Animal waste called major atmospheric ammonia source. J. Air Pollut. Control Assoc. 32:1091-1093. Bibbero, R. J., and I. G. Young, 1974. Systems Approach to Air Polution Control. John Wiley and Sons, New York, NY. Duncan, D. B., 1955. New multiple range and multiple F tests. Biometrics 11:1—42. Lebeda, D. L., 1965. Air pollutants in swine buildings. M.S. Thesis, Univ. Illinois, Urbana, IL. McAllister, J.S.V., and J. B. McQuitty, 1965. Release of gases from slurry. Minist. Agric. Res. 14:73-78. Southeastern Poultry and Egg Association, 1986. Poultry Industry Directory. Southeastern Poult. Egg Assoc, Decatur, GA. Stecher, P. G., M. Windholz, D. S. Leahy, D. M. Bolton, and L. G. Eaton, 1986. Merck Index. 8th ed. Merck and Co., Inc., Rahway, NJ. Steel, R.G.D., and J. H. Torrie, 1980. Principles and Procedures of Statistics. McGraw-Hill Book Co., New York, NY.

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' ' Means within each column with unlike letters differ significantly (P<.05). 1