Since Joseph Lister, the father of antiseptic surgery, introduced carbolic acid to a London hospital, over a hundred years ago, disinfection procedures and products have been continually improved. Nowhere is continual change and improvement more evident than in the brief history of quaternary ammonium compounds.
Benzalkonium chloride was the first commercially available quaternary, introduced in 1935. It received immediate acclaim for its broad spectrum of biocidal activity, strong detergent action, and relatively low level of toxicity. As true of many initial efforts, however, its promise exceeded its performance. Common environmental factors such as hard water, soap and anionic residues and proteinaceous soils were found to weaken its effectiveness.
The year 1955 marked the first significant improvement in quaternary technology. Two new products were developed, each stronger and more tolerant of environmental conditions than benzalkonium chloride. These second generation quaternaries demonstrated the full range of microbiocidal activity and increased hard water tolerance in the AOAC Sanitising Test.
Other industries also contributed to the continuing improvement in quaternaries. Nonionic detergents were being developed with far greater cleaning power than natural soaps. Combined with quaternaries, a truly superior detergent-disinfectant was ready to emerge.
Twin Chain quaternaries, the most significant advance in quaternary technology, came of age in 1965. Tolerances were improved beyond any earlier expectations. In the presence of hard water, Twin Chain quats remained active in water almost three times harder than found in the most extreme hard water areas. Against anionic residue, Twin Chain quats were two to three times more tolerant than earlier formulations. For years research had been dedicated to developing a compound that remained active under the most hostile conditions. Twin Chain quaternaries met these requirements.
Chemists re-directed their efforts. They sought to reduce the amount of actives and yet still maintain peak performance. They sought less toxic, less costly, more convenient disinfectants.
The answer came in 1983 when Twin Chain/ADBAC quaternaries were developed. These newest quaternaries remained active under the most difficult conditions, but with 50% fewer actives than benzalkonium chloride. Reduced actives, in turn, promised lower toxicity, improved convenience, and greater economy.
Quaternaries have always been acclaimed for biocidal strength. No single list identifies all the pathogens against which quaternary-based detergent-disinfectants have been tested, but they currently exceed 50 bacteria, viruses and fungi.
We, at MOMAR, incorporate the latest patented Twin Chain/ADBAC quaternaries in our products, SAFE! and FIRST MATE. In the USA, products that claim to kill or eliminate microbial pathogens are required to be registered with the US Environmental Protection Agency (EPA). Both SAFE! (Reg. #6836-777-1553) and FIRST MATE (Reg. #1839-86-1553) are registered with the EPA. In South Africa, both products have been registered by the South African Bureau of Standards (SABS) as required by the Compulsory Specification for Disinfectants and Detergent-disinfectants, published in Government Gazette No. 19999 of 14 May 1999 under the Standards Act. Respective registration numbers are ACT29GNR529/247367/071/528 and ACT 29GNR529/247367/071/527.
Hard Water Tolerance
Hard water has long been considered the major problem facing disinfectants. Whether a phenolic, quaternary or an iodophor, the metallic ions which are present in hard water bond to disinfectants, reducing their biocidal activity. Modern Twin Chain quaternaries used in MOMAR's products are capable of withstanding water of hardness levels two to three times harder than found in the most extreme hard water areas. As formulated in our products, we have the most hard water tolerant of all disinfectants.
Proteinaceous soils (as found in food areas and hospitals) are also known to interfere with disinfection. Quaternaries have, however, always proved to be exceptionally protein-tolerant. In fact, latest formulations retain two to three times greater biocidal activity in the presence of protein than benzalkonium chloride.
The older quaternaries are not compatible with anionic detergents, however, the latest Twin Chain/ADBAC quaternaries show exceptional tolerance to anionic detergents. What does this mean? It means that small quantities of left-over soap, detergent or any other anionic entity will not deactivate the quaternary in solution so that it will continue to kill the pathogenic organisms.
A few practitioners cling to the belief that cotton will inactivate quaternaries. Cotton, however, does not inactivate the new Twin Chain/ADBAC blends. Instead, it absorbs actives which can eventually render quaternary solutions sub-lethal to more hearty bacterial strains. So, cotton is not a problem. A well formulated detergent-disinfectant like MOMAR SAFE!, contains sufficient actives to saturate a number of cotton mops and still retain its complete spectrum of biocidal activity.
Tuberculosis is an airborne disease. This has been recognised by health care organisations such as the National Tuberculosis Association and the Centre for Disease Control in the USA. Hard surface disinfection will do little to prevent its spread. Selection of a hard surface disinfectant just because it has tuberculocidal activity will not prevent the spread of the disease, but in fact, is overlooking the more immediate threats of hard surface cross infection from: P. aeruginosa, E. Coli, S. aureus, etc. The Twin Chain/ADBAC based SAFE!, has the strength and durability to disinfect surfaces under the toughest conditions.
Evidence indicates that superior detergency produces superior disinfection. First, detergents are needed to break down soils encapsulating bacteria, enabling the disinfectant to reach the cell wall. Second, detergents remove soil from hard surfaces and also physically remove bacteria. Logic dictates that the better the detergency, the better the disinfection.
New generation quaternary formulations, such as SAFE!, generally provide better detergency than phenolic counterparts. The reasons are numerous:
1. Twin Chain/ADBAC quaternaries readily combine with nonionic detergents to perform in dual surfactant systems since they are excellent detergents themselves. Phenolics, however, are inactivated by nonionics and must be combined with soaps or anionic detergents. Neither of these offer the cleaning power of nonionics.
2. New generation quaternaries solubilise in water, freeing the detergent for cleaning. Phenolics do not solubilise in water. Soaps or detergents are needed to hold phenolics in suspension and are not available for cleaning.
3. Detergency is best accomplished at an elevated pH. Twin Chain/ADBAC quaternaries are most biocidal at a pH of 9 to 11.5. Both activities are optimised at the same pH. Phenolics achieve maximum biocidal activity at a pH of 6 to 7. Raising the pH for better detergency will reduce biocidal activity.
4. New generation quaternaries are high foaming agents, but the foam dissipates quickly, allowing faster, more thorough pick-up. Phenolic foams are much longer lasting and stable. Pick-up is slower and, frequently incomplete, leaving detergent residue on the hard surface.
5. Even in hard water, Twin Chain/ADBAC quaternaries leave no film. The soaps and anionics used in phenolic formulations are much less stable in hard water, and can leave insoluble residues on flooring. This film can produce potentially hazardous conditions.
Properly formulated and at-use dilution, MOMAR quaternary-based products are relatively safe. Unlike phenolics, no evidence exists linking quaternaries to skin-depigmentation, or hyperbilirbanemia (a blood infection). In fact, both SAFE! and FIRST MATE have a USDA authorisation code D2 which means no rinsing is required in food handling areas. In addition, MOMAR's Twin Chain/ADBAC based products can be used safely on all building materials, including vinyl, vinyl composites and linoleum.