Feasibility for Real-Time Monitoring of Bacterial Growth in Raw Milk Using a New Contactless Sensor

Area of Science:

• Food Science
• Microbiology
• Sensor Technology

Background:

• Accurate and rapid quantification of bacterial load in raw milk is crucial for ensuring dairy product safety and quality.
• Traditional microbiological methods, such as the standard plate count, are time-consuming and labor-intensive.
• There is a need for faster, greener, and more efficient methods for real-time bacterial monitoring in raw milk.

Purpose of the Study:

• To develop and validate a novel electrical bacterial growth sensor for real-time quantification of total bacterial count in raw milk.
• To compare the performance of the proposed sensor method with the standard plate count reference method.
• To assess the greenness and time efficiency of the new method for dairy quality control.

Main Methods:

• Development of a capacitively coupled contactless resonance frequency detector for monitoring bacterial metabolic activity.
• Real-time measurement of resonance frequency changes to construct bacterial growth curves without sample pretreatment.
• Application of the Gompertz model to growth curves for predictive modeling of total bacterial count.
• Validation using 55 raw milk samples and comparison with the standard plate count method.

Main Results:

• The predictive model achieved a coefficient of determination (R^2) of 0.75.
• No significant difference was observed between the proposed method and the standard plate count (t-test, 95% confidence level).
• The method demonstrated a limit of detection of 2.40 log CFU mL^-1 and a higher greenness score (0.75 vs 0.39).
• Analysis time was reduced from 48 hours to 8 hours.

Conclusions:

• The developed electrical sensor provides a feasible, rapid, and green alternative for real-time bacterial monitoring in raw milk.
• The method enables efficient classification of raw milk quality according to established regulations.
• This technology offers a promising advancement for microbiological quality control in the dairy industry.