Survival of suspensions of S. enterica on different surfaces. 3 × 106 /ml bacterial cells/ml were left on copper, steel and polymeric surfaces, and incubated at 25°C or 10°C. Alíquots were taken at 0, 2, 4 and 8 hours. The plots show the logarithm of the average from the plate counts (CFU) for each assay. The vertical bars represent the standard error of the mean (SEM) for each point A) Assay at 25°C. The differences between the bacterial counts from the copper surfaces and the control surfaces were significant at the times 2, 4 y 8 hours (P < 0.0001). B) Assay at 10°C. Differences between the bacterial counts from the copper surfaces and the control surfaces were significant at 4 hours (p < 0.05) and 8 hours (p < 0.0005).