Sensing Cellular Damages Induced by Food Safety Hazards Using Bacterial Stress-Responsive Biosensors

Area of Science:

• Microbiology
• Biotechnology
• Food Science

Background:

• Food safety hazards cause cellular damage, including DNA damage, oxidative stress, proteotoxic stress, and membrane disruption.
• Conventional toxicity assays are resource-intensive and cannot differentiate these damage types, hindering targeted risk mitigation.
• Developing specific biosensors is crucial for understanding toxic responses and improving food safety strategies.

Purpose of the Study:

• To construct a panel of Escherichia coli whole-cell biosensors capable of distinguishing distinct categories of cellular damage induced by food safety hazards.
• To develop a sensitive and cost-effective tool for practical food safety monitoring.

Main Methods:

• An optimized RecA-LexA-based biosensor was engineered for DNA damage detection.
• Systematic promoter screening identified effective modules (Pfpr, PkatG, PgrpE, PfabA) for oxidative, proteotoxic, and membrane stress biosensors.
• Biosensor specificity and sensitivity were evaluated using model toxicants and real-world samples.

Main Results:

• The DNA damage biosensor demonstrated a 36.6-fold fluorescence induction and high specificity.
• Oxidative, proteotoxic, and membrane stress biosensors showed dose-dependent responses to model toxicants.
• The DNA damage biosensor achieved a limit of detection for norfloxacin comparable to HPLC, even in milk.

Conclusions:

• The developed whole-cell biosensor panel offers a versatile, cost-effective, and sensitive method for assessing diverse cellular damages from food safety hazards.
• These biosensors can effectively discriminate between different types of cellular damage, providing valuable insights into toxicological responses.
• The study highlights the potential utility of these biosensors for practical and efficient food safety monitoring applications.