Microbiological study of the effect of a dielectric barrier discharge interaction on processed orange juices exposed to the environment

Abstract

Non-pasteurized juices may contain microorganisms that cause spoilage and public health problems. Owing to their physical properties, dielectric barrier discharge plasmas show high efficiency in the inactivation of microorganisms; in this study, coliforms, Escherichia coli and Salmonella spp. were identified in samples of orange juice collected from street stalls. Microbiological inactivation in orange juice was analyzed using the Weibull model. Using optical emission spectroscopy, the oxidant particles responsible for the inactivation of bacteria are observed. The 200 mL samples were treated for 2.5, 3.5, 5.0, and 6.0 min using a plasma with electrical power of 40 W. It was observed that for aerobic mesophilic, the colony-forming units were reduced from 4.47 to 1.00 Log; for coliforms, from 4.00 to 1.00 Log; and for yeast, from 4.75 to 3.18 Log. The evaluated physicochemical parameters indicate that there are no significant changes in the properties of the juice; therefore, the interaction process with dielectric barrier discharge is a technique that has viability in the inactivation of microorganisms and offers an alternative for the food industry in treating juices.

Effect of plasma and heat treatments on orange juice quality

“…The treatment of orange juice with dielectric barrier discharge plasmas for 2.5, 3.5, 5.0 and 6.0 min with electrical power of 40 W showed a reduction in Salmonella spp. colony forming units of 4.47 to 1.00 Log and from 4.00 to 1.00 Log for E. coli (Ocaña de Jesús et al, 2022). Liao et al (2018) also reported that, after treatment with plasma DBD in apple juice, it had a slight effect on the °Brix, pH, titratable acidity, color values, total phenolic content and antioxidant capacity of this product.…”

“…For such purpose, it is used a plasma in which the energy of the electrons is much higher than the other species. Since the plasma has a more chemical character and it is obtained at atmospheric pressure is known as cold atmospheric plasma (Ocaña de Jesús et al, 2022).…”