Choosing a hatchery disinfectant requires that you have some knowledge about the disinfectant's efficacy, how user-friendly it is, and its effect on your equipment.
By Bruce Spielholz, Preserve International, Georgia, USA
Some of the factors influencing a disinfectant's performance in a hatchery environment are hard water, organic matter and pH of the disinfectant. These factors will influence the disinfectant's efficacy asÂ well as its cosmetic appearance on equipment after use.
The vast majority of disinfectants used in hatcheries are quaternary ammonium chlorides, synthetic phenolic compounds, glutaraldehyde, combinations of glutaraldehyde and quaternary ammonium chlorides, chlorine, peroxide and iodine.
Choose your product carefully.
There is no perfect disinfectant. Each category of disinfectants has advantages and disadvantages. It is very important to remember that when a disinfectant is being evaluated, if it is, not the exact formulation of another disinfectant, even if it is of the same category, their overall performance should not be accepted as equal. Even if the active ingredients are similar in percentages, it is unlikely that the rest of that product contains the exact chemical characteristics, pH, surfactant system, chelating agents, etc. as the disinfectant it is being compared to. In other words, all quats will not perform the same, all phenolics will not perform the same, etc.
It is true that each category has characteristics that distinguish their performance. For example, quaternary ammonium chlorides do not kill tuberculosis. Another example of this is phenolics will not kill naked viruses such as infectious bursal disease or spores such as clostridium perfrigens. It does not matter how the disinfectants formulations may differ. TheÂ mode of action of the active ingredient will not allow these types of disinfectants at any level of use to kill certain microorganisms or inactivate certain viruses.
If a disinfectant does not have the ability to chemically interrupt a microorganism's life cycle or to inactivate a virus, than it does not matter what level of use is employed. This makes some disinfectants more effective against certain microorganisms and viruses than others.
Hatchery disinfectants must be able to kill the widest spectrum of microorganisms indiscriminately. It is not satisfactory for a disinfectant to be effective against only one microorganism species that may be prevalent in this type of environment such as aspergillus. Hatchery management must recognize that every microorganism has a different resistance. In fact, many microorganisms, which are in the same category such as aspergillus, have many species, which vary in their resistances to chemical action.
For this reason, the hatchery disinfectant chosen should have a past history of proven efficacy against the specific types of "problem microorganisms" which will appear in the hatchery environment.
The use of QAC
Quaternary ammonium chlorides (QAC), have been well documented for their efficacy and ease of use. They are generally inexpensive and will usually provide good results in the hatchery environment. They are most effective at an alkaline pH and do not perform especially well when challenged by organic soil. Quaternary ammonium chlorides do not provide residual activity on hard surfaces.
The biggest single problem with the use of quaternary ammonium chlorides in the hatchery environment is their inconsistent efficacy against moulds, particularly aspergillus. There are many different species of aspergillus, which exhibit different levels of resistance. QAC do not exhibit uniform kill against U types of aspergillus. As a result when hatcheries are targeting aspergillus as a problem source, the hatchery is usually unaware of the "type" of aspergillus and will consider any product, which claims to be effective against aspergillus. This approach to the aspergillus problem is usually ineffective.
For example, if the disinfectant presently being used has proven efficacy against aspergillus niger but has no proof of efficacy against aspergillus fumigatus, aspergillus glaucus, or aspergillus nidulans, you cannot assume the disinfectant is effective against these aspergillus types. A test must be conducted to determine if the disinfectant presently being used is effective against the type or types of aspergillus you are experiencing.
Most of the situations in which aspergillus persists, results in hatchery management trying to eliminate a type of aspergillus which is not affected by their "usual" disinfectant.
QAC have also had trouble in the hatchery environment with ever-present micro- organisms such as E.coli and pseudomonas, as well as aspergillus. The typical reaction to this lack of consistent efficacy is to increase usage levels. This is not the appropriate response to this problem.
Quaternary ammonium chlorides have been suspected in developing micro- organisms resistance to QAC after long periods of reappeared use. This is an obvious situation when the same types of microorganisms initially being eliminated by the QAC start reappearing and become more difficult to eliminate. E. coli, pseudomonas and aspergillus are the usual culprits. Efforts have been made by quaternary ammonium manufacturers to try to eliminate this problem by addingÂ addition- al quaternary chains. Manufacturers refer to these additions in their quaternary ammonium chlorides as "second", "third", "fourth' or "new generation" quats.
Â Cosmetic effects of Phenolics
Phenolic disinfectants have a broad range of efficacy and perform well in the hatchery environment. They are usually more expensive and due to their oil-based originÂ provide residual activity and exhibit efficacy in the presence of organic matter. They perform best in an alkaline pH. Repeated use on equipment in warm, humid conditions will result in a brown sticky residue. This cosmetic problem originates from inert ingredients used within the formulation to make the phenolics water-soluble evaporating, thus reducing the product to it soil-base origin.
These last two factors however provide a double-edged sword. If the hatchery has a sewage treatment system, the characteristics of the phenolic disinfectants high pH and organic soil tolerance will usually kill of the bacteria necessary to maintain the efficient operation of this system. Phenolics have also been used as the "cure all" when a hatchery using quaternary ammonium chlorides detect a decrease in efficacy. Sometimes this will be an effective solution and sometimes it will not. The results will depend on the efficacy of the individual phenolic chosen and if that phenolic has proven to kill the targeted microorganisms. It is incorrect to assume that any phenolic disinfectant will automatically provide efficacy against microorganisms, which quaternary ammonium chlorides will not kill.
Glutaraldehyde remains an unpopular choice
Glutaraldehyde has had limited success in the hatchery environment due to several factors. It has an extremely sensitive optimum operation pH, the range of which can be responsible for the spectrum of micro- organisms affected and the amount of time it takes to kill them. A slight pH change can result in a glutaraldehyde solution taking up to five hours to kill a microorganism such as E. coli. This contact time is not realistic in hatcheries.
Glutaraldehyde is not effective against aspergillus, but at a proper pH it is extremely effective against bacteria and hydrophilic or naked viruses. It has very good tolerance to organic matter. Glutaraldehyde is extremely offensive to the user and will usually be found in the corner of the hatchery not being used for this reason. It will also "brown' or "caramelise" the users skin at high concentrations.
Glutaraldehyde works best at an alkaline pH (8.0-8.5) but is not stable and will degrade, losing its active glutaraldehyde within 30 days in an alkaline pH.
The introductions of combinations of quaternary ammonium chlorides and glutaraldehyde have yielded disinfectants with exceptional efficacy. Incorporating QAC with glutaraldehyde allows the optimum operating pH to be just under neutral. At this pH the product is stable, and does not adversely affect hatchery waste water systems or personnel using the product. The pH in this type of product is important but not as critical as with glutaraldehyde alone.
Using QAC as a surfactant (chemical to lower surface tension) has allowed the QAC to act as a "vehicle" to bring the glutaraldehyde inside the microorganisms. This combination has been used for such practices as sterilizing medical instruments. Combining best characteristics of the QAC with the best characteristics of the glutaraldehyde have yielded a superior disinfectant.
This combination yields a synergistic effect between the QAC and glutaraldehyde, and is most efficacious when the ratio of QAC to glutaraldehyde is approximately three parts QAC to one part glutaraldehyde.
It is worth mentioning that as is the case with all disinfectants, each manufacturer's formulation of this "combination" product may differ in efficacy, cosmetic appearance and ease of use, depending on the types and amounts of active and inert ingredients contained within the formulation.
There are many products on the market, which have formulated this type of product using high levels of glutaraldehyde and low levels of quaternary ammonium chlorides. Our research indicates that when the product is formulated in this manner, the same problems that exist when using only glutaraidehyde still exist. These include inconsistent efficacy (little or no effect against mould) and a product, which is extremely offensive to use.
Formaldehyde has frequently been used as a product, which has been, employed "when all else fails". The majority of poultry producers in the US no longer rely on this product for their results, as the health concerns outweigh the results. As a known carcinogen, major companies no longer want to face the risk of employee health problems from long-term exposure.
Some of the other types of disinfectants/sanitizers, which are commonly used in the hatchery environment, are chlorine, peroxide and iodine.
The hatchery using these disinfectants/sanitizers may have success using them if they are targeted towards a specific area. Examples of this would include the use of chlorine or chlorinated cleaners on hatchery equipment, in evaporative coolers, final sanitizing lines at the tray, buggy or box washers, peroxide for egg shell disinfecting or iodine for foot dips.
Once made into solutions these products should be regularly monitored for their active ingredients, as they are sensitive to heat and light, which will cause them to degrade, lowering or completely nullifying their efficacy. Care should be taken when using these products, as they are corrosive to equipment and irritating to personnel.
Keep toxicity in mind
Remember that disinfectants, however they are marketed, are pesticides. When usage levels are increased to higher than manufacturers' recommendations, all of the cidal and toxicity levels become unknown. This is a critical point, especially when the disinfectants are being used in the presence of embryos, baby chicks, and people. While the hatchery micro-biological reports may indicate some additional efficacy, the increased usage will no doubt show up in sticky or hard chemical residues yielding equipment deterioration and poor micro- biological results, poor hatch performance from unknown toxicity, and discourage hatchery employees as they try to work in an environment where pesticides are being overused. The net result is that the hatchery employee will not use the product as instructed, yielding inconsistent hatchery results.
A sound hatchery sanitation program, using a proven disinfectant, with a continuous micro-biological monitoring program targeting hard surface, water and airborne contamination will provide you with the superior results you are seeking. The use of proportioning or metering equipment to ensure exact andÂ consistent usage of any disinfectant/sanitizer is highly recommended.