Which disinfectant is right for me?
Choosing the correct disinfectant depends on the environmental conditions surrounding the manufacturing process. First, you must know what organism you want to eliminate. Not all organisms are of high-risk concern under all circumstances. For example, in a situation when there is limited or no human interaction with the consumable product, but there are raw materials of plant origin, there will be less concern about Streptococcus, Staphylococcus or Shigella because these organisms are typically associated with human skin and excrement and transferred by the improper handling of consumables. However, contamination could come from organisms such as Escherichia coli, Salmonella and Campylobacter as these organisms are associated with soil, untreated water and livestock, all of which can ultimately be the source of contact for a raw material of botanical origin. The most effective disinfectant would be the one that can effectively kill all organisms and not be affected by the presence of organic matter, hard water or soaps/detergents. Although no single disinfectant can cover all aspects, there are many available that will provide the coverage needed for most scenarios.
A very good broad-spectrum group includes aldehyde compounds. This group of disinfectants is effective in destroying many harmful organisms including vegetative bacteria (bacteria in the actively growing state), mycobacterium, bacterial spores, enveloped viruses, non-enveloped viruses and fungi. However, they do show reduced efficacy in the presence of organic matter, hard water or soaps. The aldehyde disinfectants can be carcinogenic and are mucus membrane and tissue irritants. Therefore, they should only be used in well-ventilated areas. The least effective at killing organisms are the biguanide compounds, including chlorhexidine. Biguanide compounds are effective in eliminating vegetative bacteria, but not spores. Their effectiveness is limited against viruses and fungi. Biguanides only function in a limited pH range--5-7--which could be a problem in some work environments. Biguanide compounds also have environmental issues: they are toxic to fish.
Another good disinfectant with low to moderate cost is the phenolic group. This category of disinfectants is very effective in the presence of organic material and soaps or detergents. They are effective in eliminating vegetative bacteria and enveloped viruses. There is a varied effect on Mycobacteria, non-enveloped viruses and fungi, and it's non-sporocidal. The environmental concern is its toxicity to animals, especially cats and pigs. The two most cost-effective disinfectants are the halogen group and the quaternary ammonium compounds. The common halogen disinfectants are the hypochlorite compounds (bleach) and iodine compounds. In general, they provide a wide germicidal activity. The hypochlorite compounds are effective in eliminating vegetative bacteria, Mycobacteria, enveloped viruses, non-enveloped viruses and fungi. It has a variable effect on spores. There are some disadvantages with this disinfectant. Care must be taken to shield it from UV light as it denatures the compound and renders it useless. This compound requires frequent application to surfaces and presents another challenge in that it is highly corrosive. Moreover, like aldehyde compounds, they are mucus membrane and tissue irritants so employee safety must be considered before selecting this disinfectant. Iodine has slightly different characteristics. It effectively eliminates vegetative bacteria cells, enveloped viruses and fungi, but has a limited effect on Mycobacteria, non-enveloped viruses and bacterial endospores. The disadvantages of iodine compounds are that they are inactivated by Quaternary Ammonium compounds (Quats), which could pose a problem when iodine and Quats are used in rotation.
The next most cost-effective disinfectants are the Quats. These compounds are very stable in storage, do not irritate the skin and are effective at high temperatures and pH (9-10). However, Quats are very effective in eliminating vegetative Gram positive bacteria but have a limited effect on Gram negative bacteria. These might be useful when you are worried about spoilage caused by Gram positives such as Bacillus subtilis and lactobacillus or contamination with pathogenic Gram positives such as Staphylococcus aureus, Listeria monocytogenes, Streptococcus and Clostridium. However, Gram negatives such as Pseudomonas, Shigella, Escherichia coli and Salmonella may not be completely eliminated. It has a varied effect on Mycobacteria and enveloped viruses, and no effect on non-enveloped viruses and spores. The remaining categories are the coal tar distillates (cresol), alcohols and oxidizing agents (hydrogen peroxide). All are good broad-spectrum compounds but carry a higher cost than other disinfectants. The oxidizing agents and cresols are corrosive to work areas and the alcohols are highly flammable. The alcohols and oxidizing agents are hindered by the presence of organic matter whereas the cresols are not.
The bottom line is to determine what biological hazards might be present or of concern in your plant and, based on these, select the appropriate disinfectant. Furthermore, it is always wise to rotate the disinfectants to prevent one of those organisms that amass on your equipment from mutating and becoming resistant to the disinfectant.
For more information
Dr Cheri Turman and Benny McKee
Contact Dr Turman, Director of Chemistry
Analytical Food Laboratories
Tel. +1 800 242 6494
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|Title Annotation:||regulatory review|
|Publication:||Nutraceutical Business & Technology|
|Date:||Mar 1, 2011|
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