Aims: The response surface methodology was used to evaluate the effect of acetic acid concentration, spraying time and temperature on the reduction of Salmonella Hadar on poultry skin in a laboratory spraying process, and to identify the best conditions required to develop this operation. Methods and Results: A comparative analysis was carried out to ascertain the effects of the application of single (SS) and double sequential decontamination (DSS) treatments on skin samples inoculated with Salm. Hadar. While on the SS treatment, the linear and quadratic acid concentration terms and the interaction of the temperature and time term of the model are statistically significant at P <= 0-001, P <= 0-01 and P <= 0-05, respectively, the other terms do not significantly affect (P > 0-05) the reduction of Salm. Hadar. On the DSS model the acid concentration and time linear terms significantly affected (P <= 0-001 and P S 0-01) the Salm. Hadar reduction within the experimental range assayed. Conclusion: Any of the models could be used as an approach to optimize spray washing during chicken processing. Significance and Impact of the Study: Neither the SS or the DSS treatment has the capability of eliminating Salm. Hadar from carcasses. However, reductions of approx. 99% initial load could be attained if DSS treatment were put into practice.