These results, which parallel those obtained in our initial study, call attention to the seriousness of the high rate of sulfamethazine MRL violations in pork meat. This adds pressure not only on live- stock producers but also on management authorities in Vietnam to implement strict legislation with respect to the use of veterinary medicines. Taking into account preliminary screening strategies for on-site control, the Premi®Test would be suitable for antimicrobial monitoring in developing countries due to its low cost and simple operation. However, it should be emphasized that microbial assays can lack sufficient sensitivity, and samples should be confirmed by an LC-MS/MS method in national laboratories. Indeed, there is no doubt that the parallel combination of the Premi®Test with an LC- MS/MS multi-residue method affords one of the most powerful tools for antibiotic-residue monitoring in foods of animal origin.