CAT+finder is a test for verification of cleaning effectivenes, suitable for routine hygiene control of food contact surfaces after cleaning and disinfection. Presence of microorganisms and other undesirable residues can rapidly be detected with this test.
CAT+finder contains hydrogen peroxide as the active ingredient. Its mode of action is based on the decomposition reaction of hydrogen peroxide, which yields visible oxygen bubbles. This reaction occurs at a higher rate in the presence of catalase enzyme or residues containing high levels of metallic cations, such as blood or liver.
Catalase is an enzyme that catalyses hydrogen peroxide decomposition into water and oxygen. It is present in most living organisms exposed to oxygen, like bacteria, animals and plants, due to its protection role against reactive oxygen species. The majority of aerobic and facultative anaerobic microorganisms, as well as some anaerobic microorganisms, have the catalase enzyme, with the exception of genera such as Streptococcus, Lactobacillus, Clostridium and Mycoplasma. For this reason, catalase test has been employed as a routine biochemical test in microbiology for microorganism identification for decades.
Microbial biofilms are macromolecular structures consisting of microorganisms adhered to each other and to a surface.
These communities are embedded in an extracellular matrix formed by different macromolecules, which protects microorganisms against external aggressions such as lack of nutrients and humidity or application of biocides. Biofilm formation represents defence and survival strategy for microorganisms and, as such, most microorganisms on a surface are normally found forming part of a biofilm. For this reason, CAT+finder tests provide an indication of the potential presence of biofilm on a surface. CAT+finder contains surfactants, thickeners, dyes and stabilizer to allow for a more effective product application and easier visualization of the decomposition reaction.
CAT+finder is mainly applied for evaluation of hygiene on surfaces after cleaning and disinfection, as a complement to other techniques available. Application of CAT+finderafter hygiene procedures reveals potential presence of residues like microorganisms and some food residues.
Due to speed and ease of detection, CAT+finder can be used as a routine test for hygiene control of food contact surfaces.
1. Select a test area to sample, representative of the surface to be assessed. An area of at least 25 cm2 on a horizontal surface is recommended for product application.
2. Point the nozzle of the CAT+finder bottle towards the test area and spray the product until the area is covered.
3. Wait a minimum of 30 seconds and check the formation of bubbles.
4. Rinse the surface with water and repeat the previous steps according to the sampling plan. Formation of visible bubbles is linked to the presence of catalase-containing microorganisms or residues with high levels of metallic cations.
CAT+finder contains a dyeing agent. The product should not be applied on dye-susceptible surfaces such as fabric of porous materials. CAT+finder should also not be applied on surfaces sensitive to oxidizing agents.
Catalase enzymes from different microorganisms may have different optimum temperature activities. For this reason, intensity and rate of bubbles formation can vary according to temperature, especially at low temperatures.
Negative results can be obtained in the presence of microorganisms or food residues which have subjected to high temperatures, due to denaturalization of the catalase enzyme.
Presence of residues that do not produce hydrogen peroxide decomposition, such as microorganisms not containing the catalase enzyme, will not show positive results after application of CAT+finder.