Anais do Simpósio Latino Americano de Ciências de Alimentos
Actas del 14 SLACA - Simposio Latinoamericano de Ciencia de los Alimentos

Infant formulas have already had many problems of contamination by Salmonella around the world. This work aims to verify a model of Salmonella inactivation using ohmic heating, a well-employed emerging technology in dairy products. For each sample, 200 mL of resolubilized infant formula was used and inoculated with a pool of 5 Salmonella strains (Salmonella Typhi ATCC 19214, Salmonella Typhimurium ATCC 14028, Salmonella Agona LMQA-747, Salmonella Cubana LMQA-826 and Salmonella Mbandaka LMQA-734) to the concentration of 108 CFU mL-1. Samples were treated by ohmic heating (6 V cm-1, 60 Hz) at 50 °C (45 min), 55 °C (24 min) and 60 °C (4 min), causing reductions of 3.04, 4.69 and 5.97 log CFU mL-1, respectively. The inactivation treatments resulted in reduction rates of 0.07, 0.19 and 1.49 CFU mL-1 min-1 at 50, 55 and 60 °C, respectively. The Weibull model showed the best fit to the generated data, presenting high values of R2 (R2>0.96) and low values of RMSE (RMSE <0.34), according to add-in GinaFit for Microsoft Excel v1.7, with δ (approximate time for decay of 1 log CFU mL-1) values of 18.75, 3.24 and 0.19 min and p (indication of curve format) values of 1.27, 0.76 and 0.59 at 50, 55 and 60 °C, respectively. Based on the parameters of the primary model, it was built the secondary model formula: “log δ = -0.1994×T + 11.322”. With the secondary model formula, Salmonella concentration can be predicted at a given time of treatment, at a certain temperature between 50 and 60 °C. It can be concluded that in the tested temperature range, ohmic heating is very effective in the treatment of infant formulas against Salmonella.