Resumo

BURGUET LAGO, Nancy; BRITO GODOY, Lázaro C  e  CANOVAS BORGES, Iván. Evaluation of the effectiveness of a disinfectant through the contact plate method. Rev Cubana Farm [online]. 2013, vol.47, n.2, pp. 185-192. ISSN 0034-7515.

Objective: to evaluate the effectiveness of disinfectant LopHene ST by contact plates method. Methods: one ml of the suspension of reference microorganisms (bacteria, yeast and a filamentous fungus) was taken and spread over a surface made of a material similar to that in which the disinfectant was applied. At random positions and in three replications, the surface was sampled by the contact plates method containing Tryptone Soy Agar and Sabouraud Dextrose Agar plus neutralizing substance. Microorganisms were incubated at 32 ± 2 ºC for 3 to 5 days and at 22 ± 2 ºC for 5 to 7 days, depending on the type of microorganism to be tested. Colony-forming unit on the plates (positive control) were counted, then the prepared disinfectant (4 % concentration) was used over an equal sized area during 10 minutes. The procedure was exactly the same as in the positive control; a reduction of the number of microorganisms by at least 3 logarithms, was adopted as acceptance criteria. Results: the disinfectant reduced the bacterial concentration in a range from 4.60 to 7.20 logarithms for the three tested batches. In the case of yeast, reduction was 4.70 to 5.40 logarithms and for the filamentous fungus, the reduction ranged from 4.10 to 5.50 logarithms. Conclusions: LopHene ST disinfectant is effective for the tested microorganism strains in the evaluated time lapse and at the tested concentration. This confirms the bactericidal and fungicidal capacity of this product under the studied conditions. It was also shown that the method is valid for the analysis of effectiveness of the evaluated disinfectant batches since the colonies were reduced.

Palavras-chave : disinfectants; contact plates; reference microorganisms.

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