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Extension > Agriculture > Livestock > Good management practices for salmonella risk reduction in the production of table eggs

Good management practices for salmonella risk reduction in the production of table eggs

David A. Halvorson, DVM College of Veterinary Medicine

Copyright © 2013 Regents of the University of Minnesota. All rights reserved.

Table of contents

Chick and Pullet Replacements

Vector Control

Decontamination of Facilities

Bacteriological Monitoring

Egg Handling

Feed

Biosecurity

Appendix ÷ Educational Resources



Chick and pullet replacements

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Chickens have been found to be especially susceptible to salmonellosis from 1 to 14 days of age. Increased susceptibility also may recur when pullets are relocated to laying houses. Consequently, extra effort to reduce potential salmonella exposure and enhance bird vigor and resistance (optimal nutrition and husbandry) is highly advisable at these two critical ages.

*Excerpted with permission from the 1991 United States Animal Health Association Salmonella Committee "Integrated Guidelines for Table Egg Producers" with input from members of the Minnesota Poultry Industries Association.



Vector control

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Vector control goes beyond preparation of depopulated houses prior to cleaning and disinfection. It also is an absolutely essential risk reduction practice for the entire life of your chicks, pullets and layers. Routine, licensed professional rodent and insect detection/extermination is suggested. Be sure that personnel practice strict biosecurity procedures for their clothing, equipment and vehicles and that the service provider has a good vector control record with poultry operations. A well-illustrated, detailed publication, Integrated Pest Management for Poultry, (Arends and Stingham) is available free of charge. To order, refer to the Appendix. Purina Mills has produced a film illustrating unique techniques for rodent monitoring and control.

Rodent control details**




Decontamination of facilities

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To reduce the risks of a flock-to-flock build-up of salmonella and other infectious agents, a between-flock pullet and layer house decontamination program is necessary.

If any of your facilities tested salmonella-positive, the facility needs to be decontaminated promptly after bird removal to prevent residual contamination from infecting your replacements.

Successful decontamination programs require thorough, systematic implementation, proper equipment and professional training.

Decontamination of conventional facilities presents the table egg industry with a serious challenge due to facility size and complexity. Additionally, the common use of wooden construction materials, which are porous, appears to provide bacteria protection from the killing effects of disinfectants. Plastic and fibrous egg handling surfaces also appear to be more difficult to disinfect than non-porous metal surfaces. This problem will diminish the effectiveness of the decontamination procedures outlined in these guidelines.

Formaldehyde has been widely used in the past to help disinfect porous materials. Although particularly effective against salmonella, its use appears in jeopardy because of human safety concerns, product availability and regulatory policies. Application of alternative fumigants, heat-enhanced disinfectants, high-pressure sprays or disinfectant foams, and use of sealants to reduce wood porosity, may need to be further assessed as possible aids in disinfecting porous surfaces.

Facility decontamination needs to include the following basic considerations and precautions. Step-by-step decontamination procedures and the names and properties of various commercial disinfectants follow.

Basic considerations

Decontamination step-by-step

Additional detail on the problems of decontamination in today's industry is provided in Cleaning and Disinfecting Problems in Cage Layer Houses (Graves) and in Constructing Cage Layer Houses for Cleaning Ease (Graves). To order, refer to the Appendix.

Table 1. Properties and Examples of Common Disinfectanta a,b

Special properties Hypochlorites chloramines Iodophors Cresols phenols
Active against Gram negative 
bacteria (salmonella, E. coli, etc.
Yes Yes Yes
Resistance to organic debris Poor Poor to fair Good
Effect of hard water Nonec Nonec None
Detrimental effect of heat d d No
Residual activity e Yes Yes
Most effective pH range Acid Acid Acid
Compatibility with anionic
surfactants (soaps)
Yes Yes Yes
Compatibility with non- ionic surfactants Yes Yes No
Common brands and namesf Chloramine-T 
Chlorox 
Halazone
Betadine 
Bio-Dyne
Iodine 
Iofec
Isodyne
Losan 
R.I.D.
Tamed
Cresl-400
Environ-D 
LpH-AG 
Lysol 
Orthopheylphenols
PD 256
Tek-Trol
a Modified from Biosecurity for Poultry Lock Diseases Out (Brunet) and Selection and Use of Disinfectants in Disease Prevention (Meyerholz and Gaskin). 
b Where product types or names appear, no discrimination is intended and no endorsement over other products not mentioned is implied by the U.S. Animal Health Association (USAHA). Mention of a trade name does not constitute a guarantee or warranty of the product by the USAHA.
c Unless hard water is alkaline.
d Use at less than 1100° F; active principal driven off by heat.
e Hypochlorites: no; chloramines: yes.
f Products listed are intended as examples; many other products are not listed. New quaternary ammonium disinfectants exist.



Bacteriological monitoring

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Monitoring plans and schedules

State laws, regulations and policies vary on the confidentiality of voluntary monitoring to facilitate the acquisition of research/epidemiologic and/or in-house quality control data. Positive results at any of the bacteriological monitoring times presented below may present complex fiscal, legal and ethical issues. The same may be true for not monitoring. Professional guidance (legal, underwriter and veterinary) is essential in developing monitoring programs and choosing from the following examples for pullet and layer flocks.

 

Table 2. Examples of CHICK/PULLET Monitoring Times, Locations and Purposes

Time/Age Location Purpose
0 to 1 daya,b Chick transport papers, meconium, cull chicks and dead chicks Detection of breeder or hatchery transmitted salmonella
2 weeksc Dropping boards (cage reared) or litter surfaces (floor reared) Detection of infection after period of high susceptibility
10-16 weeks Droppings or drag swabs of manure (litter) surfaces Detection of infection prior to movement to layer facilities
2-3 days after decontamination (C & D) of pullet facility Building/equipment surfaces, fan blades, etc. Evaluation of C & D operation prior to housing new chicks
a A laboratory manual detailing sampling and culture procedures and a magazine update on culture media improvements have recently been published. For more information refer to the Appendix.
b An additional test for salmonella in one-day-old hatchlings is described in the mentioned laboratory manual (Chapter 1, page 5).
c At any age, bacteriological examination of culls, fresh deads, and trapped mice especially, are used to enhance detection efficiency.




Table 3. Examples of LAYER Monitoring Times, Locations and Purposes
Time/Age Location Purpose
10-12 weeks prior to depopulation of layer housea,b,c,d Droppings, or drag swabs of manure (litter), and building/equipment surfaces (for example, egg belts and elevators, fan blades, cages, walls, etc.) Detection of infection with adequate time for decontamination (C & D) and vaccination of pullets
2-3 days after C & D Building/equipment surfaces as listed above Evaluation of C & D operation prior to housing new pullets
a A laboratory manual detailing sampling and culture procedures and a magazine update on culture media improvements have recently been published. For more information refer to the Appendix.
b Use of cull eggs and/or blood (serum) samples are currently being evaluated as additional or alternative monitoring tools.
c At any age, bacteriological examination of culls, fresh deads, and trapped mice especially, are used to enhance detection efficiency.
d More frequent monitoring during lay has also been suggested to increase the likelihood of prompt detection of contamination.



Egg handling

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USDA and regional extension booklets detailing egg washing and sanitation practices have been published. To obtain copies, refer to the Appendix.

Basic considerations

Why refrigerate?

It is possible for the egg shell surface to become contaminated with salmonella organisms before, during, or after lay. In some instances, salmonella may contaminate the inside of the egg, either by contaminating the egg before it is fully formed, or by penetrating the shell. According to Humphrey (1990), such cases of contamination result in very few salmonella bacteria in the egg probably fewer than 10 bacteria per egg. Nonetheless, this low number can also lead to trouble.

The egg producer's goal is to eliminate or reduce unknown salmonella from the surface or the interior of the eggs produced. Proper egg washing and sanitizing has performed well in delivering a clean egg to the consumer. The question to address now is, "What about salmonella bacteria inside the egg?"

The goal of an egg handling program in addressing the possibility of internal contamination is to prevent penetrating salmonella organisms from multiplying. We have only two tools to accomplish this: the natural antibacterial properties of egg white, and low temperatures to prevent multiplication.

Egg white contains natural antibacterial products that help to kill or inhibit the growth of bacteria. In nature, this protective mechanism helps a chick hatch from an egg that is a good growth medium for bacteria as well as chicks. These natural products decline in effectiveness as the egg white ages, but they help prevent bacterial growth during the time the egg is cooling. Cool temperatures help retard the aging of egg white, and thus help maintain its antibacterial properties.

Cold temperatures alone can also prevent or reduce the growth of salmonella organisms. Research (Kim, et al, 1989) has shown that when Salmonella enteritidis was experimentally inoculated into eggs, it did not multiply at 400° F, but did multiply at 500° F. Therefore, reducing egg temperature to 450° F or lower can be used to reduce the risk of salmonella multiplication.

References:

Humphrey, T. J. Public health implications of the infection of egg-laying hens with Salmonella enteritidis phage type 4. World's Poultry Science Journal. 46:5-13. March, 1990.

Kim, C. J., D. A. Emery, H. Rinke, K. V. Nagaraja, and D. A. Halvorson. Effect of time and temperature on growth of Salmonella enteritidis in experimentally inoculated eggs. Avian Dis. 33:735-742. 1989.



Feed

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Many salmonella serotypes have been found in feed and feed ingredients. Salmonella contamination after manufacturing also needs to be prevented. Care should be exercised in selecting feed suppliers and in shipping and storing feed.


Biosecurity

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Biosecurity practices for the prevention of most virus, mycoplasma, and various bacterial diseases are equally appropriate in an integrated salmonella risk reduction program.

Salmonella best gains a foothold when a virus or other infectious agent weakens your flock's natural defenses. Research has demonstrated that bursal disease, coccidiosis, mycoplasmosis, infectious bronchitis, mycotoxicosis, and even antibiotic medication may increase susceptibility to salmonellosis. Consequently, every step in biosecurity (human traffic control, cleaning and disinfection of all materials moving between flocks, proper building location and construction, and much more) adds up to an investment in survival. Look not at biosecurity as an expense– look at it instead as an insurance premium helping to ensure a more predictable future.

Humans can also carry salmonella to your chickens and their eggs. Consequently, the personal hygiene of all farm workers is an essential consideration. Provide enough clean, operable toilets, with hand washing and drying facilities, in locations and numbers to serve all employees. Pullet and layer buildings are closer to nurseries and kitchens than many fully appreciate!

Additional materials (videotapes, pamphlets, etc.) to inspire, train, and retrain everyone in your operation are available for use at all levels, from the owner to the hired hand. (Refer to the Appendix.) Review such materials regularly. If you cannot adopt all recommended practices, adopt some of them. Then add more every year until you have built a solid defense.

Biosecurity/hygiene check lists

*Excerpted with permission from the 1991 United States Animal Health Association Salmonella Committee "Integrated Guidelines for Table Egg Producers" with input from members of the Minnesota Poultry Industries Association.

**Adapted from Diseases of Poultry. Ninth ed. 1991. Chapter 30, "External Parasites and Poultry Pests." (J. J. Arends). Pp. 727-730.

***Adapted from "Biosecurity for Poultry Lock Diseases Out." 1987. (Brunet).




Appendix
educational resources

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Biosecurity

Title Source
Biosecurity and the Poultry Industry. Video cassette. 1988. USDA, APHIS, Veterinary Services. 90 minutes. American Association of Avian Pathologists
University of Pennsylvania, New Bolton Center
Kennett Square, PA 19348-1692
$20 per cassette. (215-444-4282)
"Biosecurity for Poultry Lock Diseases Out" Extension Circular 350. Mid-Atlantic Cooperative Extension Poultry Health and Management Unit. 1987. P. Y. Brunet. 9 pp. Cooperative Extension Service, Veterinary Science
The Pennsylvania State University
University Park, PA 16802
Limited copies available.
(814-865-5573)
"Biosecurity for Poultry Stomp the Invisible Enemy." Mid-Atlantic Cooperative Extension Poultry Health and Management Unit. 1987. T. M. Nelson and E. T. Mallinson. 14 pp. T. Milton Nelson
Information and Publications
Cooperative Extension Service
Room 0126, Symons Hall
University of Maryland
College Park, MD 20742
25 cents per copy. (301-405-4596)
Diseases of Poultry. Ninth Edition. 1991. Eds. Calnek, Barnes, Beard, Reid and Yoder. 944 pp. illus., hardcover Iowa State University Press
Dept. 1787, 2121 S. State Ave.
Ames, IA 50010
$94.95 (Discount price $85.46)
(515-292-0155)
"Proposed Georgia SE Prevention Program for Pullets and Layers." 1991. Cooperatively developed by local state and federal agencies. Dr. D.C. Johnson
Area Veterinarian in Charge
USDA, APHIS, VS
1000 Iris Drive, Suite G
Conyers, GA 30207
(404-922-7860)
"Keeping Egg Production Safe from Salmonella enteritidis." Mid-Atlantic Cooperative Extension Poultry Health and Management Unit. 1989. E. T. Mallinson. Basic illustrated flyer for flock caretakers. 2 pp. Dr. E. T. Mallinson
Gudelsky Veterinary Center
University of Maryland
8075 Veterinary Science Drive
College Park, MD 20742-3711
No charge. (301-935-6083)

Cleaning and disinfection

Title Source
"Cleaning and Disinfecting Problems in Cage Layer Houses." Paper No. NAR 85-409. 1985. American Society of Agricultural Engineers. R. E. Graves. 17 pp. Dr. Robert E. Graves
201 Agricultural Engineering Bldg.
The Pennsylvania State University
University Park, PA 16802
(814-865-7155)
"Constructing Cage Layer Houses for Cleaning Ease." Special Circular 318. 1986. R. E. Graves. 11 pp. Agricultural Publications Distribution Center
112 Agricultural Building
The Pennsylvania State University
University Park, PA 16802
No charge for single copy.

Economics/legal

Title Source
"An Overview of Salmonella Litigation Liability." 1990. 7 pp. C. J. Pakuris, Esq.
Margolis, Edelstein, Scherlis, Sarowitz and Kraemer
Curtis Center, 4th Floor
Independence Square West
Philadelphia, PA 19106-3304
(215-922-1100)
"Choosing Between the Breaking Plant and the Slaughter Plant." Egg Industry. May/June 1991. Pp. 28-30. Walter Stephens
Watt Publishing Company
122 S. Wesley Avenue
Mount Morris, IL 61054
(815-734-4171)

Egg sanitation

Title Source
"Regulations Governing the Grading of Shell Eggs, etc." (7CFR Part 56). May 1991. Refer to Section 56.76, "Minimum Facility and Operating Requirements" (p. 9). Agricultural Marketing Service
Poultry Division
USDA
Washington, DC 20250
"Tips for Washing Commercial Eggs." Mid-Atlantic Cooperative Extension Poultry Health and Management Unit. 1989. Chaloupka, Reynnells and Keene. 12 pp.> T. Milton Nelson
Information and Publications
Cooperative Extension Service
Room 0126, Symons Hall
University of Maryland
College Park, MD 20742
30 cents per copy.

Evaluating products

Title Source
"Disinfection of Poultry Transport Cages." Paper No. 90-6015. 1990. American Society of Agricultural Engineers. El-Assaad, Stewart and Carr. 34 pp. Dr. Larry E. Stewart
Department of Agricultural Engineering
University of Maryland
College Park, MD 20742
(301-405-2223)
"Guidelines on Disinfection in Animal Husbandry for Prevention and Control of Zoonotic Diseases." Eds. Russell, Yanych and Koulikovskii. 62 pp. Chief, Veterinary Public Health
Division of Communicable Diseases
World Health Organization
1211 Geneva 27
Switzerland
No charge for one copy.
"Recommended Assay for Treatment of Chicks to Prevent Salmonella Colonization by Competitive Exclusion." G. C. Mead et al. Journal of Food Protection. July 1989. Vol. 52, No. 7, pp. 500-502. Journal of Food Protection
IAMFES
502 E. Lincoln Way
Ames, IA 50010-6666
(515-232-6699)

Laboratory Methods

Title Source
A Laboratory Manual for the Isolation and Identification of Avian Pathogens. Chapter 1, "Salmonellosis." Third Edition. 1989. Eds. Purchase, Arp, Domermuth and Pearson. 227 pp. American Association of Avian Pathologists
University of Pennsylvania, New Bolton Center Kennett Square, PA 19348-1692
$26 per copy
(215-444-4282)
"Novel Salmonella Detection System Developed; Combines Increased Reliability, Practicality." Feedstuffs. January 28, 1991. 4 pp. Feedstuffs
12400 Whitewater Drive, Suite 160
Minnetonka, MN 55343

Renderers

Title Source
List of 190 Animal Protein Producers Industry (APPI) participants with city and state addresses. Dr. F. D. Bisplinghoff
7150 Estero Bouevard
Fort Myers, FL 33931
(813-765-1950)

Vectors

Title Source
"Integrated Pest Management for Poultry." J. J. Arends and S. M. Stingham. 1991. 68 pp. Department of Entomology
Agricultural Extension
Box 7613
North Carolina State University
Raleigh, NC 27592-7613
No charge. (919-515-2703)

 

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