Estudo de um revestimento antimicrobiano para uso doméstico

Abstract

Kitchens are environments that contain a large number of bacteria. They are mostly harmless, but pathogens such as Salmonella and Campylobacter have also been found. The presence of these pathogens is worrying, as they accumulate in some places (refrigerators, washbasins, cutting boards and countertops) and can be transmitted to food that will be consumed, leading to the appearance of food infection. Thousands of cases of foodborne illnesses are reported every year. Thus, the objective of the present work was to determine the antimicrobial activity of a spray coating, based on quaternary ammonium compounds, applied to different surfaces, and then to evaluate its ability to prevent possible cross-contamination. First, the antimicrobial activity of the coating against Campylobacter and Salmonella isolates on stainless steel, acrylic, marble and silicone surfaces was evaluated, using the ISO 22196 (2011) method. For Campylobacter spp. it was not possible to determine its inhibition on different surfaces, as the pathogen was not able to grow under control conditions. In future work, it would be important to adjust the protocol to get around this problem. For Salmonella, great differences were found between treated and untreated surfaces, demonstrating that the coating was effective in inhibiting this pathogen. Then, the ability of the coating to prevent cross-contamination between a surface contaminated with food and a non-contaminated food was investigated. In this case, when the Salmonella pathogen was incorporated into a matrix and placed on top of a certain surface, it was not inhibited and was able to contaminate the food that was in contact with the contaminated surface. This cross-contamination occurred regardless of the food contact time (10 seconds or 2 hours) and the surface material tested. It was thus found that the coating was not effective in eliminating Salmonella when it is incorporated into a food matrix. With this work, it was verified that the coating has a good antimicrobial activity according to ISO 22196:2011. However, when the bacteria are added to a food matrix, the use of the coating does not reduce the transfer of bacteria from the surfaces to the food, showing that the food matrix protects the bacteria from the action of the coating.

Date of Award	18 Feb 2022
Original language	Portuguese
Awarding Institution	Universidade Católica Portuguesa
Supervisor	Joana Barbosa (Supervisor) & Paula Teixeira (Co-Supervisor)