2.4. Statistical analysis
Each trial was carried out 10 times, and microbiological analyses were performed in duplicate. A statistical analysis of the data was carried out by non-parametric statistics based on Kruskall–Wallis test to compare the surfaces submitted to each cleaning procedure, and Friedman's test was used to compare the different cleaning procedures with respect to each type of surface. Results were analyzed using 5% as the significance level (Conover, 1971).