- Email: [email protected]
Studies on Incubator Hygiene
Studies on Incubator Hygiene VI. A NOTE ON THE RESISTANCE OF S. PULLORUM ON STERILIZED AND UNSTERILIZED EGG SHELLS* ROBERT GRAHAM AND V.
M.
MICHAEL
University of Illinois, Vrbana, Illinois (Received for publication, July 19, 1936)
N STUDIES heretofore reported, S. pullorum contaminated egg shells placed in petri dishes in hatching trays on the floor near the hatching trays and on the interior of false doors in two forced draft incubators were subjected to formaldehyde fumigation. Formaldehyde was released with potassium permanganate as well as directly from cheesecloth. Thirty-five cc of formalin and 17.5 grams of potassium permanganate per hundred cubic feet and 22 cc of formalin per hundred cubic feet with the cheesecloth method of release were employed. In 25 separate fumigations by each of the above methods, 5. pullorum was destroyed in 10 to 22 minutes with a viability range of 40 minutes. In an occasional fumigation S. pullorum on egg shells survived longer than 40 minutes, although the exact length of time was not determined. This fact, together with the possible presence of S. pullorum on the egg shell from infected hens prompted further fumigation studies on germicidal efficiency of formaldehyde in destroying S. pullorum. To note the difference, if any, in the viability of S. pullorum on egg shells previously sterilized as well as on unsterilized shells and to obtain additional information on the viability of S. pullorum, unsterilized egg shells and sterilized egg shells were *A Smith Junior forced draft incubator was employed in these studies, and the eggs for hatching purposes were purchased with funds provided by Smith Incubator Company.
artificially contaminated with S. pullorum and subjected simultaneously to formaldehyde fumigation in a forced draft incubator. Technk. Egg shells were cut into 1 x }4inch rectangles. One-half of the shell rectangles were autoclaved in petri dishes at 15 pounds steam pressure for 30 minutes. The remaining one-half were not sterilized in any way; fresh shells were used for each fumigation. The sterilized and unsterilized egg shells (in separate containers) were immersed in physiological salt suspension of 5. pullorum, strain K271, density of tube 1 of McFarland's nephelometer. The S. pullorum contaminated egg shells were exposed in petri dishes in hatching trays at the time formaldehyde (20 cc formalin per 100 cubic feet) was released in the forced draft incubator by the cheesecloth method. The wet bulb temperature reading was kept at 90-92 °F., and the dry bulb at 99-100°F. Following the release of formaldehyde S. pullorum contaminated egg shells were removed from petri dishes in the incubator at 10 and 20-minute intervals and the fumigated egg shells were dropped into a tube of sterile nutrient broth which was incubated at 37°C. Subcultures were made from the broth tubes by streaking nutrient agar plates at the end of 24 and 48 hours' incubation. Three separate fumigations of S. pullorum contaminated egg shells with 6,000, 15,000, and 20,000 eggs in the incubator gape comparable results, which are illustrated in the following tabulation.
[490]
Downloaded from http://ps.oxfordjournals.org/ at New York University on April 18, 2015
I
VOL.
XV,
No.
491
6 Non-Sterilized Egg Shells
Sterilized Egg Shells
48 hrs.
+++1111+
Control (no fumigation) Shells fumigated 10 min. 20 min. 30 min. 40 min. 60 min. 80 min. 100 min.
24 hrs.
111111++
Incubation
Incubation 72 hrs.
+
24 hrs. Control (no fumigation) Shells fumigated 10 min. 20 min. 30 min. 40 min. 60 min. 80 min. 100 min.
48 hrs.
11111+++
1936.
1 1 1 1 1 1 ++
NOVEMBER,
SUMMARY
1. In three separate fumigations of a forced draft incubator (formaldehyde released from cheesecloth 20 cc per hundred cubic feet), there appeared to be very little variance in the longevity of S. pullorum on egg shells which had been sterilized at 15 pounds steam pressure for 30 minutes and for those which had not been sterilized previous to contamination with S. pullorum. 2. S. pullorum on egg shells in hatching trays survived formaldehyde fumigation for 30 minutes. After 40 minutes S. pullorum was generally non-viable although in one fumigation it survived for 100 minutes on sterilized egg shells. 3. The survival of S. pullorum on egg shells during formaldehyde fumigation of a forced draft incubator for 100 minutes
suggests the advisability of keeping the incubator closed for at least two hours following fumigation. 4. The range of S. pullorum viability in empty incubators, as previously reported, appears comparable to the results of these experiments in which a 32,000 capacity incubator carried 6,000, 15,000, and 20,000 eggs. In 25 separate fumigations, however, S. pullorum that occasionally survived 40 minute fumigation may have had a range of 100 minutes. REFERENCES
Graham, Robert and V. M. Michael, 1932 b. Studies on incubator hygiene, II. Poul. Sci. 11:197-207. , 1933. Incubator hygiene in the control of pullorum disease. 111. Agr. Exp. Sta. Cir. 403.
Downloaded from http://ps.oxfordjournals.org/ at New York University on April 18, 2015
+ = S. pullorum viable. — = n o growth.
M.
MICHAEL
University of Illinois, Vrbana, Illinois (Received for publication, July 19, 1936)
N STUDIES heretofore reported, S. pullorum contaminated egg shells placed in petri dishes in hatching trays on the floor near the hatching trays and on the interior of false doors in two forced draft incubators were subjected to formaldehyde fumigation. Formaldehyde was released with potassium permanganate as well as directly from cheesecloth. Thirty-five cc of formalin and 17.5 grams of potassium permanganate per hundred cubic feet and 22 cc of formalin per hundred cubic feet with the cheesecloth method of release were employed. In 25 separate fumigations by each of the above methods, 5. pullorum was destroyed in 10 to 22 minutes with a viability range of 40 minutes. In an occasional fumigation S. pullorum on egg shells survived longer than 40 minutes, although the exact length of time was not determined. This fact, together with the possible presence of S. pullorum on the egg shell from infected hens prompted further fumigation studies on germicidal efficiency of formaldehyde in destroying S. pullorum. To note the difference, if any, in the viability of S. pullorum on egg shells previously sterilized as well as on unsterilized shells and to obtain additional information on the viability of S. pullorum, unsterilized egg shells and sterilized egg shells were *A Smith Junior forced draft incubator was employed in these studies, and the eggs for hatching purposes were purchased with funds provided by Smith Incubator Company.
artificially contaminated with S. pullorum and subjected simultaneously to formaldehyde fumigation in a forced draft incubator. Technk. Egg shells were cut into 1 x }4inch rectangles. One-half of the shell rectangles were autoclaved in petri dishes at 15 pounds steam pressure for 30 minutes. The remaining one-half were not sterilized in any way; fresh shells were used for each fumigation. The sterilized and unsterilized egg shells (in separate containers) were immersed in physiological salt suspension of 5. pullorum, strain K271, density of tube 1 of McFarland's nephelometer. The S. pullorum contaminated egg shells were exposed in petri dishes in hatching trays at the time formaldehyde (20 cc formalin per 100 cubic feet) was released in the forced draft incubator by the cheesecloth method. The wet bulb temperature reading was kept at 90-92 °F., and the dry bulb at 99-100°F. Following the release of formaldehyde S. pullorum contaminated egg shells were removed from petri dishes in the incubator at 10 and 20-minute intervals and the fumigated egg shells were dropped into a tube of sterile nutrient broth which was incubated at 37°C. Subcultures were made from the broth tubes by streaking nutrient agar plates at the end of 24 and 48 hours' incubation. Three separate fumigations of S. pullorum contaminated egg shells with 6,000, 15,000, and 20,000 eggs in the incubator gape comparable results, which are illustrated in the following tabulation.
[490]
Downloaded from http://ps.oxfordjournals.org/ at New York University on April 18, 2015
I
VOL.
XV,
No.
491
6 Non-Sterilized Egg Shells
Sterilized Egg Shells
48 hrs.
+++1111+
Control (no fumigation) Shells fumigated 10 min. 20 min. 30 min. 40 min. 60 min. 80 min. 100 min.
24 hrs.
111111++
Incubation
Incubation 72 hrs.
+
24 hrs. Control (no fumigation) Shells fumigated 10 min. 20 min. 30 min. 40 min. 60 min. 80 min. 100 min.
48 hrs.
11111+++
1936.
1 1 1 1 1 1 ++
NOVEMBER,
SUMMARY
1. In three separate fumigations of a forced draft incubator (formaldehyde released from cheesecloth 20 cc per hundred cubic feet), there appeared to be very little variance in the longevity of S. pullorum on egg shells which had been sterilized at 15 pounds steam pressure for 30 minutes and for those which had not been sterilized previous to contamination with S. pullorum. 2. S. pullorum on egg shells in hatching trays survived formaldehyde fumigation for 30 minutes. After 40 minutes S. pullorum was generally non-viable although in one fumigation it survived for 100 minutes on sterilized egg shells. 3. The survival of S. pullorum on egg shells during formaldehyde fumigation of a forced draft incubator for 100 minutes
suggests the advisability of keeping the incubator closed for at least two hours following fumigation. 4. The range of S. pullorum viability in empty incubators, as previously reported, appears comparable to the results of these experiments in which a 32,000 capacity incubator carried 6,000, 15,000, and 20,000 eggs. In 25 separate fumigations, however, S. pullorum that occasionally survived 40 minute fumigation may have had a range of 100 minutes. REFERENCES
Graham, Robert and V. M. Michael, 1932 b. Studies on incubator hygiene, II. Poul. Sci. 11:197-207. , 1933. Incubator hygiene in the control of pullorum disease. 111. Agr. Exp. Sta. Cir. 403.
Downloaded from http://ps.oxfordjournals.org/ at New York University on April 18, 2015
+ = S. pullorum viable. — = n o growth.