TSA Letheen Agar (Irradiated)

Description

• The combination of lecithin and polysorbate 80 neutralizes the quaternary ammonium compounds.
• The polysorbate 80 neutralizes hexachlorophene and mercurial derivatives.
• Lecithin neutralizes chlorhexidine.

Note: Contact plates are used for monitoring the microbiological contamination of surface and air inside cleanrooms, isolators, RABS, food industries and hospitals. The double/triple irradiated wrapping ensures that the package itself doesn't contaminate the environment as the first wrapper is removed just before entering the clean area.

Technique

In the microbiological control of cleaning and disinfection of surfaces in the "clean zones" the contact plates are used as a plug or copy-pad that acts simultaneously as a sampler and culture medium to be incubated, without other intermediate operations. For this, the 65 mm diameter plates are filled so that the medium forms a suitable meniscus to produce a contact surface of approximately 25 cm².

At the time of use, remove the outer shell of the plates, remove the cover of the plate and rest the culture medium on the surface to be controlled, exerting a gentle pressure for about 10-15 seconds, to ensure good contact between the two surfaces. The plate is removed without rubbing and covered with its cover to avoid contamination. They are labeled appropriately with the sampling data (place, date and time) and are incubated. The inoculated plates are incubated at 35 ± 2 °C for 18-24 h (bacteria).

When the effectiveness of a cleaning and/or disinfection process is verified, sampling with the contact plates should be done within two hours of the completion of the process, ensuring that the surfaces to be sampled are dry. Positive controls should always be included, sampling the area prior to disinfection or simultaneously monitoring unclean areas adjacent to the disinfected area.

The frequency of cleaning/disinfection and subsequent sampling will be established by the responsible technician, depending on the results obtained and the proposed objectives.

The plates must be kept in their original packaging (blisters) to guarantee their stability until the end of their expiration date.

Physical/chemical control

• ATLAS, R.M. & L.C. PARKS (1993) Handbook of Microbiological Media. CRC Press, Inc. London.
• COLIPA (1997) Guidelines on Microbial Quality Management (MQM). Brussels.
• DOWNES, F.P. & K. ITO (2001) Compendium of Methods for the Microbiological Examination of Food, 4th ed, ASM, Washington D.C.
• EUROPEAN PHARMACOPOEIA 10.0 (2020) 10th ed. § 2.6.13. Microbiological examination of non-sterile products: Test for specified microorganisms. Harmonised Method. EDQM. Council of Europe. Strasbourg.
• FDA (Food and Drug Administration) (1998) Bacteriological Analytical Manual. 8th ed. Rev. A. AOAC International. Gaithersburg. MD.
• HORWITZ, W. (2000) Official Methods of Analysis of AOAC INTERNATIONAL, 17th ed. Gaithersburg, MD. USA.
• ISO 9308-1 Standard (2000) Water Quality. Detection and enumeration of E. coli and coliform bacteria. Membrane filtration method.
• ISO 11731 Standard (2017) Water Quality - Enumeration of Legionella.
• ISO 11133:2014/Amd 1:2018. Microbiology of food, animal feed and water. Preparation, production, storage and performance testing of culture media.
• ISO 18415 Standard (2017) Cosmetics - Microbiology - Detection of specified and non-specified microorganisms.
• ISO 21149 Standard (2017) Cosmetics - Microbiology - Enumeration and detection of aerobic mesophilic bacteria.
• ISO 21150 Standard (2015) Cosmetics - Microbiology - Detection of Escherichia coli.
• ISO 22717 Standard (2015) Cosmetics - Microbiology - Detection of Pseudomonas aeruginosa.
• ISO 22718 Standard (2015). Cosmetics - Microbiology - Detection of Staphylococcus aureus.
• ISO 22964 (2017) Microbiology of the food chain - Horizontal method for the detection of Cronobacter spp.
• PASCUAL ANDERSON, Mª R. (1992) Microbiología Alimentaria. Díaz de Santos S.A., Madrid.
• USP 33 - NF 28 (2011) <62> Microbiological examination of non-sterile products: Test for specified microorganisms. Harmonised Method. USP Corp. Inc. Rockville. MD. USA.