Inactivation of milk-borne pathogens by blue light exposure.

Area of Science:

• Food Science
• Microbiology
• Photochemistry

Background:

• Dairy industry requires effective microbial decontamination methods.
• Thermal processing compromises milk's organoleptic and nutritional qualities.
• Blue light offers a non-thermal alternative for microbial inactivation.

Purpose of the Study:

• To determine blue light inactivation kinetics against specific pathogens in milk.
• To investigate potential degradation of milk components by blue light.
• To assess blue light as a food safety solution for the dairy sector.

Main Methods:

• Irradiation of bacterial suspensions (Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Salmonella Typhimurium, Mycobacterium fortuitum) in milk and saline with blue light (413 nm).
• Kinetic analysis of microbial inactivation.
• Optical spectroscopy (infrared) to evaluate milk component stability.

Main Results:

• All tested bacterial species showed significant inactivation (>5 log10) within 2 hours.
• Inactivation rates varied between bacterial species and suspension media (milk vs. saline).
• No significant degradation of milk sugars, proteins, or lipids was observed; only riboflavin showed degradation.

Conclusions:

• Blue light photoinactivation is a highly effective antimicrobial strategy for dairy applications.
• This method preserves milk's nutritional and organoleptic properties.
• Blue light offers a promising, non-thermal technology for enhancing food safety in the dairy industry.