Draft Written By Dr. Shahn Bisschop <Shahn@avimune.co.za>
Study Objective
To determine if Peroxsil Ag+ could be used as a replacement for formalin fogging of hatching eggs.
Introduction
In order to improve egg hygiene, hatching eggs are routinely fogged at broiler breeder farms using formalin. Formalin, although considered effective, poses a health hazard to staff working with it, and the South African poultry industry is looking for effective replacement products.
When done correctly, formalin fumigation is highly effective at reducing eggshell contamination; however, fumigation is not always done successfully due to fluctuations in temperature and relative humidity in fumigation units. This makes results inconsistent.
Peroxsil Ag+, on the other hand, does not rely on temperature and relative humidity parameters for optimal performance and therefore does not have the same infrastructure requirements as formalin fumigation. It is also easier to achieve more consistent results with the product.
Peroxsil Ag+ application is safer than formalin fumigation – safety precautions are required when working with the concentrated chemical, but once diluted, it poses little hazard to staff, and it breaks down into water & oxygen when exposed to the environment.
The authors did a series of on-farm trials to try to answer the following questions:
Does the application of Peroxsil Ag+ reduce bacterial contamination of eggshells?
In order to answer this question, the shells of hatching eggs were treated with Peroxsil Ag+, and bacterial contamination of untreated eggshells was compared with bacterial levels in treated eggs.
Results
The average bacterial count for untreated eggs was 49.6 cfu per eggshell and for eggs treated with clean water, 55.8 cfu. Treatment with Peroxsil resulted in a lower average bacterial count of only 2.6 cfu per eggshell. Peroxsil Ag+ reduced the bacterial load on the eggshells.
Discussion
There was a substantial reduction in the bacterial load of treated eggs as compared to similar eggs from the same egg collection. Additional eggs were treated with water containing no disinfectants in order to confirm the observed decrease in bacteria in bacteria in bacterial load on the eggs treated with Peroxil was not simply a result of bacteria being flushed off the egg surface by the application of liquid to the eggshells. Egg shells rinsed with only water showed a similar level of bacterial contamination to untreated eggs, confirming that the observed improvement was probably due to the action of the Peroxil, rather than a simple rinsing effect.
Answer
The available data indicate that treatment of eggshells with Peroxil Ag+ effectively reduces the bacterial load on the eggshell.
Does the application of Peroxsil Ag+ reduce bacterial contamination of eggshells of dirty floor eggs, and does this reduce the contamination of the egg contents as well?
In a second related test, the shells of untreated dirty floor eggs with faecal contamination (n=40) were compared with eggshells rinsed with water (n=20), eggshells treated with Peroxide Ag+ (n=40,) and eggshells rinsed with water and treated with Peroxil Ag+ (n=20).
The contents of similar dirty floor eggs (n=20) were also tested for bacterial contamination and compared with eggs treated with Peroxil (n=20) to confirm that reduced contamination of the eggshells resulted in reduced bacterial contamination of the egg contents.
Results
The graph below shows the results of samples from eggshells of dirty floor eggs.
The graph below shows the results of the culture of the egg contents of dirty floor eggs.
The average number of colony-forming units in each swab sample from the egg contents was 6.75 in the rinsed eggs and 0.50 among the eggs treated with Peroxsil.
Discussion
This test was carried out after the results from the first test suggested that Peroxsil might be effective in reducing the bacterial contamination of eggshells. Dirty floor eggs were selected as it was anticipated that the bacterial contamination levels of eggs obviously contaminated with faecal material would be greater than relatively clean first grade hatching eggs, making them also more difficult to sterilize with a disinfectant product. Eggshells counts among dirty, untreated floor eggs, averaged 98.2 CFUs per area tested compared with 49.6 CFUs per area for hatching eggs. Or put another way, 38/40 dirty floor eggs tested were severely contaminated with bacteria, while 8/40 hatching eggs were severely contaminated.
Treatment with Peroxsil reduced bacterial contamination of the eggshells to undetectable levels on all the treated eggshells, confirming the efficacy of the product in this role.
Egg contents were sampled in this group as well, to determine if clean eggshells correlated with clean inner egg contents. Peroxil treatment reduced contamination of egg contents from an average of 6.75 CFUs per swab to 0.5 CFUs per egg content swab, indicating that the product was effective as measured by this matrix as well.
Answer
The available data suggests that the lower bacterial counts on eggshells result in lower bacterial contamination of the egg contents.
Is Peroxil Ag+ as effective as formalin for eggshell disinfection?
In order to answer this question, the bacterial contamination of the shells of a total of 480 hatching eggs on seven different production sites were compared. Groups of eggs were tested before any treatment and compared to eggs treated with Peroxil Ag+ as well as eggs from the same sites fumigated with formalin using the fumigation facilities of a large poultry integrator.
Results
The results are shown by site in the graphs below.
The graph below shows the average level of bacterial contamination before treatment. All eggshells were heavily contaminated with bacteria. Laboratory procedure is to count to 100 cfu per eggshell, with 101 as the maximum possible value, indicating “too numerous to count”.
The graph below shows the average level of bacterial contamination after treatment – either with formalin or with Peroxil Ag +.
The graph above shows that both treatments reduced the bacterial counts on the eggshells. In the case of Peroxil Ag+ bacterial contamination was completely eliminated from many of the eggs, while bacterial counts on eggs treated with formalin remained high and on one site appears to have been ineffective. For consistent results with formalin fumigation, the entire process needs to be carefully managed and monitored.
The graph below summarizes the results obtained across all the sites that were tested.
Discussion
A high level of bacterial contamination was detected on all eggshells before formalin fumigation and Peroxil Ag+ treatment. Both treatments reduced the bacterial load of the eggshells, but Peroxil Ag+ treatment reduced average contamination to only 4 viable bacteria per eggshell.
It appears that the Peroxil Ag+ treatment was more effective than formalin fumigation in this specific test. The formalin fumigation process was not evaluated by the study team.
Answer
The trial data indicates that Peroxil Ag+ is effective at reducing the bacterial count on eggshells at least as effectively as formalin fumigation.
Do the Peroxsil Ag+ treated eggs remain clean after delivery and grading at the hatchery?
To answer this question, a total of 160 eggs were tested on arrival at the hatchery after treatment on the sites.
Results
The Peroxil Ag+ group showed lower bacterial counts on the eggshells than the formalin treated group. Counts remained low during storage until setting.
Answer
Bacterial counts remained low counts on Peroxil treated eggshells.
Is fogging with Peroxil Ag + effective?
A small pilot study was done where eggs were cold fogged with Peroxil Ag+. Bacterial counts were reduced by about 50% but results were inconsistent, and the method is not recommended at this stage. It appears that there is insufficient airflow between egg trays when they are in the egg trollies to ensure reliable application.
Answer
Fogging eggs in trolleys does not appear to be effective and is not presently recommended.
Does Peroxil Treatment have a Beneficial Effect on hatchability?
Eggs from 4 different farms were split into separate formalin fumigation and Peroxil Ag+ treatment groups and hatched and the results confirmed.
Results
A total of 20 hatches were compared. This included approximately 377 000 eggs treated using Peroxil Ag+ and approximately 420 000 eggs that were fumigated using formalin. See table below for the details of the trial. Of the 20 pairwise comparisons that could be made, in 15 cases the hatch of first grade chicks was better in the Peroxil Ag+ treated group than for the eggs fumigated with formalin.
First grade chicks – Peroxil Ag + treatment – 84.02%
First grade chicks – Formalin fumigation – 83.70%
Answer
The available data indicates that the eggs treated with Peroxil Ag+ hatched at least as well as the eggs treated with formalin fumigation. This is to be expected where the bacterial load on the eggshells is effectively reduced, as they were during this trial by the Peroxil Ag+ treatment.
Does Peroxil treatment have an effect on broiler product results?
Broiler production data for these sites is unfortunately not available.
SUMMARY
Overall, this project shows the potential of Peroxil Ag+ treatment to reduce the level of bacterial contamination of hatching eggs.
Methods
Product Application and Dilution
Peroxil Ag+ contains a 50% concentration of Hydrogen Peroxide. Peroxil Ag+ was diluted 1:64 with cold clean tap water thus giving a concentration of 0.78% Hydrogen Peroxide in the final solution.
Water quality was not tested on the day of the test. Water on the farm is routinely tested twice annually for bacterial contamination. Bacterial load is typically low – suitable for human consumption (SANS 241 standard) with a pH of about 7.6.
The solution was applied to the surface of the eggs using a battery powered knapsack sprayer to deliver sufficient liquid to completely wet each egg. The spray was applied to the top and bottom of the eggs, eggs were not removed from the setter trays during treatment. Approximately 350mL was applied to each egg tray containing 150 hatching eggs.
No other cleaning, disinfection or fumigation was applied to any eggs on the site.
Sampling for Eggshell Testing
After treatment, each egg was removed from the setter tray using a pair of tongs that were sanitized using alcohol after each egg was sampled. The egg was then held with a finger at each end and the entire circumference of the egg rolled across the contact paddle – see image below.
Sampling
Egg Hygiene Scoring System
|
Efficacy % |
Bacterial Count |
|
100 % |
ND cfu/plate |
|
80 % |
1-10 cfu/plate |
|
60 % |
11-25 cfu/plate |
|
40 % |
26-60 cfu/plate |
|
20 % |
61-100 cfu/plate |
|
0 % |
>100 cfu/plate |
NB colony forming units (cfu) only counted to a maximum of 101 bacterial colonies per plate.
Egg Content Sampling
(We need the details of this method as well.) I will get these from Christine at SMT Vet lab.
