Effect of Optimized UV-LED Technology on Modeling, Inactivation Kinetics and Microbiological Safety in Tomato Juice

Area of Science:

• Food Science
• Microbiology
• Chemical Engineering

Background:

• Pathogenic bacteria, including Escherichia coli O157:H7 and Listeria monocytogenes, pose significant risks to tomato juice safety.
• Traditional preservation methods like heat treatment can impact the quality of food products.

Purpose of the Study:

• To optimize UV-LED irradiation parameters for inactivating pathogenic bacteria in tomato juice.
• To model the inactivation kinetics of Escherichia coli O157:H7 and Listeria monocytogenes using UV-LED treatment.
• To compare the microbiological safety of UV-LED processed tomato juice with heat-treated juice.

Main Methods:

• Response surface methodology (RSM) was employed to optimize UV-LED processing conditions (power intensity, time, wavelength).
• The Weibull model was utilized to analyze the inactivation kinetics of target pathogens.
• Microbiological safety was assessed by enumerating surviving bacteria (CFU/mL) and comparing UV-LED treatment with heat treatment over 28 days.

Main Results:

• Optimal UV-LED conditions (90% power, 21 min, 273-275 nm) achieved significant log reductions of Escherichia coli O157:H7 (2.89 CFU/mL) and Listeria monocytogenes (2.74 CFU/mL).
• The Weibull model accurately estimated pathogen inactivation, with kinetic parameters indicating specific UV-LED doses required for 90% reduction.
• UV-LED treated tomato juice exhibited a 11.4% lower Listeria monocytogenes count compared to heat-treated juice after 28 days.

Conclusions:

• UV-LED irradiation is a viable technology for inactivating Escherichia coli O157:H7 and Listeria monocytogenes in tomato juice, enhancing microbiological safety.
• Further research is needed to improve inactivation efficacy and explore UV-LED applications in other fruit and vegetable juices.