Turbidity influence in the antimicrobial effect of the ultraviolet light and luminous pulses of white light in orange nectar (citrus sinensis)

Abstract

This investigation aimed to determine the influence of the level of turbidity in the antimicrobial effect of ultraviolet light on orange nectar (Citrus sinensis L.). The investigation was conducted in a chamber treatment UVC light with walls of mirror and a lamp ultraviolet light of 15 watts. The nectar, subjected to a process of pasteurization (90 °C, 10 minutes), were inoculated with freeze-dried yeast (Saccharomyces cerevisiae), strain MIT L51, until concentrations of 1.0, 0.1 and 0.01% (w/p) and determine the turbidity of the dilutions, reporting turbidity values of 10564, 1304 and 813 NTU respectively. The samples were exposed to three different doses, 0.57, 1.14 and 1.71 J/cm2 taking a sample witness called "0" minutes, for purposes of initial analysis of microorganisms. Subsequent to the implementation of treatment took place in the tally sheets, amid Sabouraud agar. Obtained data in the reading of the resulting colonies determined the survival rate in each treatment and value the constant decimal reduction "D" in J/cm2 . These data showed that the turbidity, due to the dissolved solids, adversely influence the antimicrobial activity of UVC light. We concluded that antimicrobial activity expressed in terms of constant decimal reduction "D", under these conditions treatment in the nectar of orange, depends directly and indirectly of the turbidity of the total energy transmitted.

Keywords

• Antimicrobial activity
• constant decimal reduction
• UVC light
• turbidity
• nontermal pasteurization.