Essential oils (EOs) are mostly composed of terpenes and phenolic compounds that are stored in secretory tissues of aromatic plants. This study evaluated the effect of both commercial and experimental thyme oil (cEO and eEO, respectively) on ATCC strains of Salmonella enteritidis and Salmonella paratyphi present on surfaces of chilled raw beef. The composition of each EO was analyzed chemically by gas chromatography coupled with spectrometry (GC-MS). The antimicrobial activity was assessed through the agar diffusion method and the minimum inhibitory concentration by means of the macro dilution method in broth, thus proving that a higher concentration of both cEO and eEO is required to reduce the growth of S. enteritidis compared to S. paratyphi. Similar results were obtained when pieces of beef previously inoculated with 10 4 cfu / ml and kept at 0°C, 4°C and 10°C for 72 hours were treated with three concentrations of cEO and eEO. The in vivo approach showed that S. paratyphi is more sensitive to the action of EO than S. enteritidis and such sensitivity decreases when temperature increases. Overall, the cEO proved to be more effective than the eEO on the growth inhibition of the two species, showing in all cases a reduction greater than 10% for S. paratyphi at the concentration of 50% (v / v) and greater than 7% at the concentrations of 40 and 30% (v / v), exhibiting a significant variation at a p-value < 0.05. Regarding S. enteritidis, the values of reduction were 4.5% at 0°C and 4°C and 3.5% at 10°C for the cEO, and higher than 1% for the eEO.It is concluded that the application of thyme EO on surfaces of meat contributes to reduce the presence of Salmonella spp. on this type of foodstuff.