A spectroscopy-based proof-of-concept (POC) for developing loading of pathogen analyzer (LOPA) for dairy products.

Area of Science:

• Food Science
• Analytical Chemistry
• Microbiology

Background:

• Bacterial contamination in dairy products poses a global challenge.
• Accurate microbial quantification is crucial for ensuring dairy product safety and quality.

Purpose of the Study:

• To develop and validate a proof-of-concept (POC) device for in-field detection of bacterial contamination in milk.
• To utilize the Methylene Blue Reduction Test (MBRT) for microbial quantification in dairy products.

Main Methods:

• Employed the Methylene Blue Reduction Test (MBRT) principle, observing colorimetric changes (MB to Leuco-MB).
• Developed a spectroscopy-based POC device to measure the decrease in methylene blue absorbance at 664 nm.
• Calibrated and validated the POC using pasteurized milk spiked with *Escherichia coli* and *Staphylococcus aureus*.

Main Results:

• The developed POC accurately detected microbial contamination by measuring methylene blue discoloration.
• Achieved a limit of detection (LOD) of 0.32 CFU/mL and a limit of quantitation (LOQ) of 0.97 CFU/mL.
• Demonstrated significant changes in methylene blue absorption in contaminated milk samples, with sensor strips turning colorless.

Conclusions:

• The developed spectroscopy-based POC offers a reliable method for quantifying microbial contamination in milk.
• This technology has potential for widespread application in the dairy industry for quality control and public health protection.
• The indigenously developed sensor strips and device provide a practical solution for in-field dairy product testing.