Enhancing Biocide Safety of Milk Using Biosensors Based on Cholinesterase Inhibition

Area of Science:

• Electrochemistry
• Biosensor Technology
• Analytical Chemistry

Background:

• Benzalkonium chloride (BAC) and didecyldimethylammonium chloride (DDAC) are widely used biocides in the agri-food sector.
• Accurate detection of these biocides is essential for ensuring food safety and regulatory compliance.
• Existing detection methods may face challenges with complex sample matrices like milk.

Purpose of the Study:

• To develop and validate a sensitive electrochemical biosensor for BAC and DDAC detection.
• To assess the biosensor's performance in a relevant matrix (milk).
• To establish a reliable method for monitoring biocide levels in dairy products.

Main Methods:

• Immobilization of acetylcholinesterase (DM AChE) and butyrylcholinesterase (BChE) on screen-printed electrodes.
• Development of an electrochemical detection strategy for BAC and DDAC.
• Implementation of a liquid-liquid extraction technique for sample preparation.
• Validation of the biosensor against European regulatory limits.

Main Results:

• Achieved low limits of detection (LODs) in buffer: 0.26 µM for BAC (BChE) and 0.04 µM for DDAC (DM AChE).
• Observed a significant decrease in sensitivity when testing directly in milk samples.
• Demonstrated that liquid-liquid extraction restored sensor sensitivity and accuracy in milk.
• Confirmed compliance with European Union regulations for dairy products (max 0.28 µM).

Conclusions:

• The developed electrochemical biosensor shows promise for biocide detection.
• Sample pretreatment (liquid-liquid extraction) is critical for accurate analysis in milk.
• The method provides a reliable tool for monitoring BAC and DDAC in the agri-food industry, meeting regulatory standards.