Abstract

Metallic handles loops are calibrated instruments used to quantify colonies in microbiological studies. These handles loops are expensive and the most common presentations are those made of platinum wire or nickel – chrome alloys. In order to look for more economic alternatives, it has been proposed the employment of common alloys, in wire presentation with varied diameters. It is important to know how different liquid and flame expositions can affect wire morphology, because it is a determining feature for applicability of certain alloys. In this study, metallic handles loops made of pure metals or alloy wires were used, such as: Fe-Zn, Ni-Cr, Cu and Au. They were used in the microbiological laboratory and sterilized in a flame approximately 500 to 2000 times before using them in the microscopic study. An Scanning Electron Microscope, Hitachi S-2300, was used under the Secondary Electrons (SE) mode with different zooms. Morphological changes were observed on the metallic surfaces of each loop sample and of v irgin sample for every wire (not exposed to the flame). Results indicated that morphological modifications are present accordingly to the number of flame sterilizations. Metallic handles loops made of Fe-Zn and Ni-Cr presented the least damage on their surface, followed by those made of Cu, whereas those made of Au suffered the major damage / wear / build up, even though they were the least used.