594
N. TRAKULCHANG AND S. L. BALLOUN
nitrogen from urea to the low-protein diet. In Experiment 3, some improved gains were observed and
might indicate a
tendency
toward a reduced rate of ammonia release from urea when intestinal microbial activity was reduced by 3-nitro-phenyl arsonic acid. REFERENCES Featherston, W. R., H. R. Bird and A. E. Harper, 1962. Ability of the chick to utilize D- and excess L-indispensable amino acid nitrogen in the synthesis of dispensable amino acids. J. Nutr. 78: 95-100. Kazemi, R. S., 1972. Urea and diammonium citrate utilization by poultry. Ph.D. Thesis, Iowa State University, Department of Animal Science, Ames, Iowa. Kazemi, R., and S. L. Balloun, 1972. Effect of urea
and diammonium citrate on fecal components of chicken hens. Poultry Sci. 51: 1480-1481. Lee, D. J. W., and R. Blair, 1972. Effects on chick growth of adding various nonprotein nitrogen sources or dried autoclaved poultry manure to diets containing crystalline essential amino acids. Br. Poultry Sci. 13: 243-249. National Research Council, 1971. Nutrient requirements of poultry. National Academy of Sciences, Washington, D.C. Reid, B. L., 1967. Nonprotein nitrogen studies with poultry. Georgia Nutr. Conf. Proc. 1967: 73-81. Steel, R. G. D., and J. H. Torrie, 1960. Principles and Procedures of Statistics. McGraw-Hill Book Company, Inc., New York. Sullivan, T. W., and H. R. Bird, 1957. Effect of the quality and source of dietary nitrogen on the utilization of the hydroxy analogues of methionine and glycine by chicks. J. Nutr. 62: 143-150.
Effect of Filtering Recycled Air in a Chick Hatcher on Airborne Pathogenic Microorganisms1,2 JOHN S. AVENS, CAREY L. QUARLES AND DIANE J. FAGERBERG
Department of Animal Sciences, Colorado State University, Fort Collins, Colorado 80523 (Received for publication July 29, 1974)
ABSTRACT Two experimental chick hatchers in which ventilation air within the hatcher was partially recirculated in a positive pressure system, one with an air filter in the system and the other without a filter, were simultaneously tested to determine effect of the filter on quantitative reduction of viable airborne microorganisms. Chicks were artificially contaminated with either Escherichia coli or Staphylococcus aureus (coagulase-positive). Air was sampled for total test bacteria per cubic foot of hatcher air. The filter effectively reduced the number of viable airborne particles contaminated with E. coli and S. aureus contributed by chicks in the hatcher. POULTRY SCIENCE 54: 594-599, 1975
INTRODUCTION
M
various other airborne particles which are
ICROORGANISMS on or in a few
prevalent in the hatcher a few hours before
hatching
the hatch is completed. Pathogenic Escher-
eggs
can
be
throughout the hatcher by air
distributed movement
ichia coli -contaminated eggs can account for
during hatching and thus contaminate or in-
extensive
fect all other chicks in the machine. Microor-
conditions, i.e.,
chick mortality.
ganisms may be carried on chick down and
Staphylococcus
injury,
Under
some
certain
strains
of
aureus may cause acute or
chronic disease to chicks. Magwood (1964) observed a direct relationship between air1. Published with the approval of the Director of the Colorado State University Experiment Station as Scientific Series paper number 1991. 2. This research was supported in part by Robbins Incubator Company, Project 6535.
borne microorganisms and the amount of contamination of various hatchery surfaces. If the amount of airborne particles carrying microorganisms could be significantly
re-
595
AIRBORNE PATHOGENIC MICROORGANISMS
duced in the hatcher, there would be less chance of contamination and infection of the hatched chicks. An experimental hatcher was designed so air leaving the hatching chamber was filtered and recirculated in a positive pressure ventilation system. The hypothesis
tested was that many of the viable airborne particles would adhere to the filter and would not be free to circulate throughout the hatching chamber. A filter was tested for its ability to reduce the number of viable airborne microorganisms in an experimental chick hatcher. MATERIALS AND METHODS
FIG. 1. Experimental chick hatcher. Side and front panels have been removed to show blower, heater, humidifier, cooling coil and filter in conditioning compartment. Door to the hatching compartment is open.
Fertile eggs were obtained from caged Single Comb White Leghorn hens that were artificially inseminated twice each week. Eggs were incubated in a Robbins Hatch-OMatic incubator for 18.5 days before transferring 360 to each of two similar experimental hatchers, one containing a filter and one control (no filter). The experimental hatchers were designed by Robbins Incubator Company with a hatching chamber and conditioning chamber, separated by a filter in one of the hatchers (Fig. 1, 2). The conditioning chamber contained heater, cooling coil, humidifier and humidistat. Ventilation air within the hatcher was recycled in a positive pressure system, and was filtered
TEMPERATURE SENSORS
HATCHING COMPARTMENT BLOWER
CONDITIONING COMPARTMENT (CONTAINS HEATERS, COOLING COILS, HUMIDIFIER, HUMIDISTAT, ETC)
ILTER
TEST HATCHER
FIG. 2. Experimental chick hatcher—schematic, front view, "x" indicates where air sampling probes were inserted.
596
J . S . AVENS, C . L . QUARLES AND D . J . F A G E R B E R G
in the filter containing hatcher. Experimental hatchers were both in the same room which was equipped with an exhaust fan. Hatchers were thoroughly cleaned, disinfected with a synthetic phenol solution and fumigated with formaldehyde before each experiment. The hatchery room was also cleaned and disinfected before each experiment. Effectiveness of the filter in reducing viable airborne particles was determined by artificial contamination of hatched chicks with pure cultures of Escherichia coli in three experiments and of Staphylococcus aureus (coagulase-positive) in three experiments. A 12-hour culture of the specific test organism in Trypticase Soy Broth (BBL) containing 2 percent Yeast Extract (BBL) was placed in the hatchers after the majority of the chicks had pipped and 12 hours before air sampling. Specific volumes of the 12-hour culture were pipetted into sterile, plastic petri dishes containing folded paper tissue ("Kim-Wipes"). One petri dish containing the culture-saturated tissue was placed open in the center of each of the four hatching trays—5 ml. on bottom tray, 10 ml. on each middle tray and 15 ml. on the top tray. These open culture dishes were a source of airborne particle contamination since many of the hatched chicks walked through, fell in and/or pecked at the culture, thus contaminating their down. E. coli, as evidenced by relatively low counts in Experiments 1 and 2, was apparently quite susceptible to the relatively harsh airborne environment. Therefore, to achieve more comparable E. coli particle counts between the hatchers a slightly modified procedure for airborne particle contamination was adopted. An additional culture dish with 10 ml. of liquid E. coli culture prepared identical to the other dishes was placed on the hatching chamber floor in each hatcher, beneath the hatching trays. Thus, five E. coli culture dishes were in each hatcher but only four were directly accessible to the hatched chicks. This additional culture dish allowed
some organisms to remain in a more optimal liquid nutrient environment throughout the exposure period and perhaps still become airborne on particles due to air movement. Air was sampled with the Andersen Viable Sampler (Model 10-000) (Fig. 3) operated according to the "Instructions for Operation and Care of the Andersen Viable Sampler" (1971). Levine Eosin Methylene Blue Agar (Difco) and Vogel and Johnson Agar (BBL), culture medium specific for differentiating E. coli and S. aureus (coagulase-positive), respectively, were used in the air sampler. Consecutive air samples were taken first from the conditioning chamber followed by the hatching chamber of the filter containing and control hatchers. Sampling probes were inserted through ports in front of each chamber of the hatchers just prior to sampling. Each probe was 26 inches (66 cm.) long made of unpainted copper tubing (1-1/16 inch [2.7
FIG. 3. Andersen Viable Sampler in place at end of sampling probe. Sampling probe sealed in place around hatcher port.
597
AIRBORNE PATHOGENIC MICROORGANISMS
cm.] I.D.) with one 90° bend facing down in front of the hatcher and was flange-gasketed for a friction-tight seal around the hatcher ports (Fig. 3). Down did not collect in the bend during the air sampling time. The Andersen Viable Sampler was gasketed for a friction-tight connection to the end of the probe (Fig. 3). One probe extended into the center of each conditioning chamber just above the floor; the other into the center of each hatching chamber below the bottom tray. The protruding end of each probe remained closed until the sampler was attached. Air sampling time varied between experiments from ten seconds to two minutes. Air flow through the sampler was one cubic foot (28.3 liters) per minute. After sampling, plates were incubated at 35-37° C. for 24 hours to determine viable bacterial particle counts. Viable particle counts were determined by the "positive hole" method (Andersen Air Samplers, 1971). RESULTS AND DISCUSSION Experiment 1—Escherichia coli. The viable airborne E. coli particle counts from the hatchers were relatively low (Table 1). The hatching chamber of the filter containing hatcher had fewer viable airborne E. coli particles (10 per ft.3 air) than the hatcher without filter (25 per ft.3 air). No viable airborne E. coli particles were detected in the conditioning chamber of the filter containing hatcher, compared to 29 per ft.3 air in the hatcher without filter. TABLE 1.— Viable Escherichia coli particles per cubic foot of hatcher air
Experiment!—Escherichia coli. T h e E . coli counts in the hatcher without filter were relatively low, but the even lower counts from the filter containing hatcher indicated the filter removed the few viable airborne particles carrying E. coli from the filtered hatcher air. Experiment 3—Escherichia coli. Presumably because of the additional source of viable organisms, the E. coli viable particle counts from the hatcher without filter were higher (100 and 73 per ft.3 air) than in the first two experiments (Table 1). This allowed a more revealing comparison of viable airborne E. coli particle counts between the two hatchers. For the third consecutive experiment not a single viable E. coli particle was detected in the conditioning chamber of the filter containing hatcher. Since considerably more viable airborne E. coli particles were detected from the hatcher without filter, the filter very effectively reduced the number of viable airborne particles carrying E. coli in the filter containing hatcher. Experiments 4, 5 and 6—Staphylococcus aureus. All three experiments involving S. aureus indicated the filter was effective in reducing the number of viable airborne S. aureus particles in the hatcher (Table 2). Reductions of 64 percent, 99 percent and 98 percent occurred from the hatching chamber of the control hatcher compared to the hatchTABLE 2.— Viable Staphylococcus aureus (coagulase-positive) particles per cubic foot of hatcher air Chamber
Chamber Experiment
Hatcher
Hatching
1
Filtered Control
2
Filtered Control
10 25 1 4
3
Filtered Control
2 100
Conditioning
Experiment
0 29
4
0 6
5
0 73
6
Hatcher
Hatching
Conditioning
Filtered Control Filtered Control
10,000 28,000
100 23,000
250 34,000
170 17,000
Filtered Control
530 29,000
36 24,000
598
J. S. AVENS, C. L . QUARLES AND D . J. FAGERBERG
ing chamber of the filter containing hatcher in experiments 4, 5 and 6, respectively. In the filter containing hatcher, reductions of 99 percent, 32 percent and 93 percent occurred from the hatching chamber compared to the conditioning chamber in experiments 4, 5 and 6, respectively.
A few viable S. aureus organisms were able to penetrate the filter and be detected in the conditioning chamber whereas no E. coli were detected in the conditioning chamber of the filter containing hatcher (Tables 1 and 2). Relatively few E. coli organisms (4-100 per ft.3 air) remained viable
TABLE 3.— Total and stage S. aureus colony counts (viable particles per cubic foot of hatcher air)
Experiment
Hatcher
Viable sampler stage"
Filtered Total
Control Total
Filtered Total
Control Total
Filtered Total
Control
Chamber Conditioning 2 0 6 58 364 36 36 2 0 10,268 104 7,656 8,456 6,856 7,656 5,700 6,056 5,592 550 2,152 100 4 2 22,820 27,960 120 6 24 0 66 48 24 78 12 36 0 0 246 168 3,180 1,128 5,586 2,358 17,904 6,966 6,120 5,466 978 702 30 12 33,798 16,632 204 0 90 6 114 0 90 12 36 18 0 0 534 36 3,366 1,488 4,872 4,470 13,680 11,742 6,096 5,700 684 582 12 18
Hatching 5,442 2,724 1,702
28,710 24,000 Total "Stage 1 is at the top of the Andersen Viable Sampler and is first to contact the sampled air followed consecutively by stages 2, 3, 4, 5 and 6 which is on the bottom of the sampler.
AIRBORNE PATHOGENIC MICROORGANISMS
in the airborne condition compared to S. aureus (28,000-34,000 per ft.3 air) in the control hatching chamber. Samples of room air taken immediately after hatcher air samples for each experiment revealed no detectable E. coli and 14, 27 and 170 S. aureus particles per cubic foot of room air in experiments 4, 5 and 6, respectively. S. aureus is a skin and respiratory system contaminating pathogen frequently transmitted through air, whereas E. coli is an intestinal organism. E. coli apparently was much more severely affected by the airborne environment than S. aureus under these experimental conditions. Andersen (1958) discloses the pore size in each succeeding stage of the Andersen Viable Sampler is smaller, causing the jet velocity to be greater in each succeeding stage. Each succeeding stage removes a top fraction (largest particles) of all the particles, impingement on the solid medium surface of a particular stage being dependent on the aerodynamic dimensions of the particles. Stages one and two, which have the larger pores and collect the larger particles, revealed relatively few viable S. aureus particles from the filtered conditioning chamber with the exception of stage six which collects only the smallest particles (Table 3). The larger airborne particles carrying viable S. aureus were apparently quite effectively trapped by the filter (Table 3—filter containing hatcher, conditioning vs. hatching
599
chamber). Smaller viable particles which needed higher jet velocity to leave the air stream in the sampler were not as effectively trapped by the filter. These smaller particles impinged on the media at the fourth and fifth stages yielding relatively high colony counts. The size of the viable particles as determined by the viable sampler stage on which they were impinged, seemed directly related to the effectiveness of the filter-—the larger the particle and the less jet velocity necessary for impingement, the more effective the filter was in trapping it. The filter effectively reduced the number of viable airborne particles contaminated with pathogenic Escherichia coli and Staphylococcus aureus contributed by artificially contaminated chicks in the filter containing experimental hatcher. Substantial reduction of viable airborne particles contaminated with pathogenic microorganisms during hatch should reduce morbidity and mortality of the birds during growth. REFERENCES Andersen, A. A., 1958. New sampler for the collection, sizing and enumeration of viable airborne particles. J. Bact. 76: 471-484. Andersen Air Samplers, 1971. Instructions for Operation and Care of the Andersen Viable Sampler, 2000 Inc., Salt Lake City. pp. 1-3. Magwood, S. E., 1964. Studies in hatchery sanitation. 3. The effect of airborne bacterial population on contamination of egg and embryo surfaces. Poultry Sci. 43: 1567-1572.
NEWS AND NOTES (Continued from page 561) and albumen quality processing problems. Dr. John R. Hunt has transferred to the Agassiz Research Station from the Animal Research Institute, Canada Agriculture, Ottawa. He has made major contributions in areas of techniques for measuring
egg shell strength and rations for reducting egg shell breakage. This move to Agassiz will enable Dr. Hunt to become more involved with industry problems. Already he is investigating a leg weakness problem in broiler chicks. His major efforts will be devoted
(Continued on page 614)
N. TRAKULCHANG AND S. L. BALLOUN
nitrogen from urea to the low-protein diet. In Experiment 3, some improved gains were observed and
might indicate a
tendency
toward a reduced rate of ammonia release from urea when intestinal microbial activity was reduced by 3-nitro-phenyl arsonic acid. REFERENCES Featherston, W. R., H. R. Bird and A. E. Harper, 1962. Ability of the chick to utilize D- and excess L-indispensable amino acid nitrogen in the synthesis of dispensable amino acids. J. Nutr. 78: 95-100. Kazemi, R. S., 1972. Urea and diammonium citrate utilization by poultry. Ph.D. Thesis, Iowa State University, Department of Animal Science, Ames, Iowa. Kazemi, R., and S. L. Balloun, 1972. Effect of urea
and diammonium citrate on fecal components of chicken hens. Poultry Sci. 51: 1480-1481. Lee, D. J. W., and R. Blair, 1972. Effects on chick growth of adding various nonprotein nitrogen sources or dried autoclaved poultry manure to diets containing crystalline essential amino acids. Br. Poultry Sci. 13: 243-249. National Research Council, 1971. Nutrient requirements of poultry. National Academy of Sciences, Washington, D.C. Reid, B. L., 1967. Nonprotein nitrogen studies with poultry. Georgia Nutr. Conf. Proc. 1967: 73-81. Steel, R. G. D., and J. H. Torrie, 1960. Principles and Procedures of Statistics. McGraw-Hill Book Company, Inc., New York. Sullivan, T. W., and H. R. Bird, 1957. Effect of the quality and source of dietary nitrogen on the utilization of the hydroxy analogues of methionine and glycine by chicks. J. Nutr. 62: 143-150.
Effect of Filtering Recycled Air in a Chick Hatcher on Airborne Pathogenic Microorganisms1,2 JOHN S. AVENS, CAREY L. QUARLES AND DIANE J. FAGERBERG
Department of Animal Sciences, Colorado State University, Fort Collins, Colorado 80523 (Received for publication July 29, 1974)
ABSTRACT Two experimental chick hatchers in which ventilation air within the hatcher was partially recirculated in a positive pressure system, one with an air filter in the system and the other without a filter, were simultaneously tested to determine effect of the filter on quantitative reduction of viable airborne microorganisms. Chicks were artificially contaminated with either Escherichia coli or Staphylococcus aureus (coagulase-positive). Air was sampled for total test bacteria per cubic foot of hatcher air. The filter effectively reduced the number of viable airborne particles contaminated with E. coli and S. aureus contributed by chicks in the hatcher. POULTRY SCIENCE 54: 594-599, 1975
INTRODUCTION
M
various other airborne particles which are
ICROORGANISMS on or in a few
prevalent in the hatcher a few hours before
hatching
the hatch is completed. Pathogenic Escher-
eggs
can
be
throughout the hatcher by air
distributed movement
ichia coli -contaminated eggs can account for
during hatching and thus contaminate or in-
extensive
fect all other chicks in the machine. Microor-
conditions, i.e.,
chick mortality.
ganisms may be carried on chick down and
Staphylococcus
injury,
Under
some
certain
strains
of
aureus may cause acute or
chronic disease to chicks. Magwood (1964) observed a direct relationship between air1. Published with the approval of the Director of the Colorado State University Experiment Station as Scientific Series paper number 1991. 2. This research was supported in part by Robbins Incubator Company, Project 6535.
borne microorganisms and the amount of contamination of various hatchery surfaces. If the amount of airborne particles carrying microorganisms could be significantly
re-
595
AIRBORNE PATHOGENIC MICROORGANISMS
duced in the hatcher, there would be less chance of contamination and infection of the hatched chicks. An experimental hatcher was designed so air leaving the hatching chamber was filtered and recirculated in a positive pressure ventilation system. The hypothesis
tested was that many of the viable airborne particles would adhere to the filter and would not be free to circulate throughout the hatching chamber. A filter was tested for its ability to reduce the number of viable airborne microorganisms in an experimental chick hatcher. MATERIALS AND METHODS
FIG. 1. Experimental chick hatcher. Side and front panels have been removed to show blower, heater, humidifier, cooling coil and filter in conditioning compartment. Door to the hatching compartment is open.
Fertile eggs were obtained from caged Single Comb White Leghorn hens that were artificially inseminated twice each week. Eggs were incubated in a Robbins Hatch-OMatic incubator for 18.5 days before transferring 360 to each of two similar experimental hatchers, one containing a filter and one control (no filter). The experimental hatchers were designed by Robbins Incubator Company with a hatching chamber and conditioning chamber, separated by a filter in one of the hatchers (Fig. 1, 2). The conditioning chamber contained heater, cooling coil, humidifier and humidistat. Ventilation air within the hatcher was recycled in a positive pressure system, and was filtered
TEMPERATURE SENSORS
HATCHING COMPARTMENT BLOWER
CONDITIONING COMPARTMENT (CONTAINS HEATERS, COOLING COILS, HUMIDIFIER, HUMIDISTAT, ETC)
ILTER
TEST HATCHER
FIG. 2. Experimental chick hatcher—schematic, front view, "x" indicates where air sampling probes were inserted.
596
J . S . AVENS, C . L . QUARLES AND D . J . F A G E R B E R G
in the filter containing hatcher. Experimental hatchers were both in the same room which was equipped with an exhaust fan. Hatchers were thoroughly cleaned, disinfected with a synthetic phenol solution and fumigated with formaldehyde before each experiment. The hatchery room was also cleaned and disinfected before each experiment. Effectiveness of the filter in reducing viable airborne particles was determined by artificial contamination of hatched chicks with pure cultures of Escherichia coli in three experiments and of Staphylococcus aureus (coagulase-positive) in three experiments. A 12-hour culture of the specific test organism in Trypticase Soy Broth (BBL) containing 2 percent Yeast Extract (BBL) was placed in the hatchers after the majority of the chicks had pipped and 12 hours before air sampling. Specific volumes of the 12-hour culture were pipetted into sterile, plastic petri dishes containing folded paper tissue ("Kim-Wipes"). One petri dish containing the culture-saturated tissue was placed open in the center of each of the four hatching trays—5 ml. on bottom tray, 10 ml. on each middle tray and 15 ml. on the top tray. These open culture dishes were a source of airborne particle contamination since many of the hatched chicks walked through, fell in and/or pecked at the culture, thus contaminating their down. E. coli, as evidenced by relatively low counts in Experiments 1 and 2, was apparently quite susceptible to the relatively harsh airborne environment. Therefore, to achieve more comparable E. coli particle counts between the hatchers a slightly modified procedure for airborne particle contamination was adopted. An additional culture dish with 10 ml. of liquid E. coli culture prepared identical to the other dishes was placed on the hatching chamber floor in each hatcher, beneath the hatching trays. Thus, five E. coli culture dishes were in each hatcher but only four were directly accessible to the hatched chicks. This additional culture dish allowed
some organisms to remain in a more optimal liquid nutrient environment throughout the exposure period and perhaps still become airborne on particles due to air movement. Air was sampled with the Andersen Viable Sampler (Model 10-000) (Fig. 3) operated according to the "Instructions for Operation and Care of the Andersen Viable Sampler" (1971). Levine Eosin Methylene Blue Agar (Difco) and Vogel and Johnson Agar (BBL), culture medium specific for differentiating E. coli and S. aureus (coagulase-positive), respectively, were used in the air sampler. Consecutive air samples were taken first from the conditioning chamber followed by the hatching chamber of the filter containing and control hatchers. Sampling probes were inserted through ports in front of each chamber of the hatchers just prior to sampling. Each probe was 26 inches (66 cm.) long made of unpainted copper tubing (1-1/16 inch [2.7
FIG. 3. Andersen Viable Sampler in place at end of sampling probe. Sampling probe sealed in place around hatcher port.
597
AIRBORNE PATHOGENIC MICROORGANISMS
cm.] I.D.) with one 90° bend facing down in front of the hatcher and was flange-gasketed for a friction-tight seal around the hatcher ports (Fig. 3). Down did not collect in the bend during the air sampling time. The Andersen Viable Sampler was gasketed for a friction-tight connection to the end of the probe (Fig. 3). One probe extended into the center of each conditioning chamber just above the floor; the other into the center of each hatching chamber below the bottom tray. The protruding end of each probe remained closed until the sampler was attached. Air sampling time varied between experiments from ten seconds to two minutes. Air flow through the sampler was one cubic foot (28.3 liters) per minute. After sampling, plates were incubated at 35-37° C. for 24 hours to determine viable bacterial particle counts. Viable particle counts were determined by the "positive hole" method (Andersen Air Samplers, 1971). RESULTS AND DISCUSSION Experiment 1—Escherichia coli. The viable airborne E. coli particle counts from the hatchers were relatively low (Table 1). The hatching chamber of the filter containing hatcher had fewer viable airborne E. coli particles (10 per ft.3 air) than the hatcher without filter (25 per ft.3 air). No viable airborne E. coli particles were detected in the conditioning chamber of the filter containing hatcher, compared to 29 per ft.3 air in the hatcher without filter. TABLE 1.— Viable Escherichia coli particles per cubic foot of hatcher air
Experiment!—Escherichia coli. T h e E . coli counts in the hatcher without filter were relatively low, but the even lower counts from the filter containing hatcher indicated the filter removed the few viable airborne particles carrying E. coli from the filtered hatcher air. Experiment 3—Escherichia coli. Presumably because of the additional source of viable organisms, the E. coli viable particle counts from the hatcher without filter were higher (100 and 73 per ft.3 air) than in the first two experiments (Table 1). This allowed a more revealing comparison of viable airborne E. coli particle counts between the two hatchers. For the third consecutive experiment not a single viable E. coli particle was detected in the conditioning chamber of the filter containing hatcher. Since considerably more viable airborne E. coli particles were detected from the hatcher without filter, the filter very effectively reduced the number of viable airborne particles carrying E. coli in the filter containing hatcher. Experiments 4, 5 and 6—Staphylococcus aureus. All three experiments involving S. aureus indicated the filter was effective in reducing the number of viable airborne S. aureus particles in the hatcher (Table 2). Reductions of 64 percent, 99 percent and 98 percent occurred from the hatching chamber of the control hatcher compared to the hatchTABLE 2.— Viable Staphylococcus aureus (coagulase-positive) particles per cubic foot of hatcher air Chamber
Chamber Experiment
Hatcher
Hatching
1
Filtered Control
2
Filtered Control
10 25 1 4
3
Filtered Control
2 100
Conditioning
Experiment
0 29
4
0 6
5
0 73
6
Hatcher
Hatching
Conditioning
Filtered Control Filtered Control
10,000 28,000
100 23,000
250 34,000
170 17,000
Filtered Control
530 29,000
36 24,000
598
J. S. AVENS, C. L . QUARLES AND D . J. FAGERBERG
ing chamber of the filter containing hatcher in experiments 4, 5 and 6, respectively. In the filter containing hatcher, reductions of 99 percent, 32 percent and 93 percent occurred from the hatching chamber compared to the conditioning chamber in experiments 4, 5 and 6, respectively.
A few viable S. aureus organisms were able to penetrate the filter and be detected in the conditioning chamber whereas no E. coli were detected in the conditioning chamber of the filter containing hatcher (Tables 1 and 2). Relatively few E. coli organisms (4-100 per ft.3 air) remained viable
TABLE 3.— Total and stage S. aureus colony counts (viable particles per cubic foot of hatcher air)
Experiment
Hatcher
Viable sampler stage"
Filtered Total
Control Total
Filtered Total
Control Total
Filtered Total
Control
Chamber Conditioning 2 0 6 58 364 36 36 2 0 10,268 104 7,656 8,456 6,856 7,656 5,700 6,056 5,592 550 2,152 100 4 2 22,820 27,960 120 6 24 0 66 48 24 78 12 36 0 0 246 168 3,180 1,128 5,586 2,358 17,904 6,966 6,120 5,466 978 702 30 12 33,798 16,632 204 0 90 6 114 0 90 12 36 18 0 0 534 36 3,366 1,488 4,872 4,470 13,680 11,742 6,096 5,700 684 582 12 18
Hatching 5,442 2,724 1,702
28,710 24,000 Total "Stage 1 is at the top of the Andersen Viable Sampler and is first to contact the sampled air followed consecutively by stages 2, 3, 4, 5 and 6 which is on the bottom of the sampler.
AIRBORNE PATHOGENIC MICROORGANISMS
in the airborne condition compared to S. aureus (28,000-34,000 per ft.3 air) in the control hatching chamber. Samples of room air taken immediately after hatcher air samples for each experiment revealed no detectable E. coli and 14, 27 and 170 S. aureus particles per cubic foot of room air in experiments 4, 5 and 6, respectively. S. aureus is a skin and respiratory system contaminating pathogen frequently transmitted through air, whereas E. coli is an intestinal organism. E. coli apparently was much more severely affected by the airborne environment than S. aureus under these experimental conditions. Andersen (1958) discloses the pore size in each succeeding stage of the Andersen Viable Sampler is smaller, causing the jet velocity to be greater in each succeeding stage. Each succeeding stage removes a top fraction (largest particles) of all the particles, impingement on the solid medium surface of a particular stage being dependent on the aerodynamic dimensions of the particles. Stages one and two, which have the larger pores and collect the larger particles, revealed relatively few viable S. aureus particles from the filtered conditioning chamber with the exception of stage six which collects only the smallest particles (Table 3). The larger airborne particles carrying viable S. aureus were apparently quite effectively trapped by the filter (Table 3—filter containing hatcher, conditioning vs. hatching
599
chamber). Smaller viable particles which needed higher jet velocity to leave the air stream in the sampler were not as effectively trapped by the filter. These smaller particles impinged on the media at the fourth and fifth stages yielding relatively high colony counts. The size of the viable particles as determined by the viable sampler stage on which they were impinged, seemed directly related to the effectiveness of the filter-—the larger the particle and the less jet velocity necessary for impingement, the more effective the filter was in trapping it. The filter effectively reduced the number of viable airborne particles contaminated with pathogenic Escherichia coli and Staphylococcus aureus contributed by artificially contaminated chicks in the filter containing experimental hatcher. Substantial reduction of viable airborne particles contaminated with pathogenic microorganisms during hatch should reduce morbidity and mortality of the birds during growth. REFERENCES Andersen, A. A., 1958. New sampler for the collection, sizing and enumeration of viable airborne particles. J. Bact. 76: 471-484. Andersen Air Samplers, 1971. Instructions for Operation and Care of the Andersen Viable Sampler, 2000 Inc., Salt Lake City. pp. 1-3. Magwood, S. E., 1964. Studies in hatchery sanitation. 3. The effect of airborne bacterial population on contamination of egg and embryo surfaces. Poultry Sci. 43: 1567-1572.
NEWS AND NOTES (Continued from page 561) and albumen quality processing problems. Dr. John R. Hunt has transferred to the Agassiz Research Station from the Animal Research Institute, Canada Agriculture, Ottawa. He has made major contributions in areas of techniques for measuring
egg shell strength and rations for reducting egg shell breakage. This move to Agassiz will enable Dr. Hunt to become more involved with industry problems. Already he is investigating a leg weakness problem in broiler chicks. His major efforts will be devoted
(Continued on page 614)
