Application of Low Wavelength UV-C Irradiation for Treating Mycotoxins in Turbid Fluids

Introduction: Patulin, a mycotoxin produced by several genera of fungi, including Aspergillus and Penicillium, has been an important concern in apple-based products due to its toxicity. Ultraviolet (UV) irradiation is a sterilization method effective against a range of bacteria and viruses while being non-thermal and non-adulterating in its mechanism of action. This makes UV irradiation a unique and attractive method to control mycotoxins in fluids.

Purpose: The objective of this study was to evaluate the effect of UV irradiation in combination with a photosensitizer (ATZ1) on patulin stability.

Methods: Experiments were conducted using a collimated beam system operating at 254 nm wavelength. Appropriate fluence correction factors were accounted when quantifying the UV dose. Chemical profiling was conducted using HPLC. Kinetic modeling supplemented with two-way ANOVA was performed at 5 percent significance level to assess the effectiveness of UV irradiation along with the application of photosensitizer on patulin stability.

Results: Patulin reduction by UV irradiation followed the first-order kinetic model. It clearly indicated that patulin sensitivity to UV irradiation is relatively high. If UV irradiation is used alone, doses close to 4000 mJcm^-2 could only reduce patulin concentration by 45% (P < 0.05).  Under this scenario, the doses delivered to patulin molecule were very high, higher than the dose required for the microbial inactivation. Using photosensitizer, ATZ1 in combination with UV irradiation caused a significant reduction in patulin concentration, 75% reduction in patulin concentration at 400 mJcm^-2 (P < 0.05).

Significance: The findings in this study only serve as a proof of concept of using UV technology for patulin degradation in turbid fluids. Application of UV irradiation along with photosensitizer (ATZ1) process can aid in reducing patulin concentration for highly turbid liquid foods.