Advantages and limitations of a novel hybrid biosensor for detecting toxic compounds in food

Abstract

A hybrid biosensor for rapid detection of several toxic compounds in foods is hereby described. This device employs a non-invasive electrochemical sensor based on a potentiometric gas diffusion carbon dioxide electrode coupled with specific microbial cultures. Determinations are based on the perturbation of the respiration activity of an appropriate microorganism in the presence of different toxic compounds. Escherichia coli and Bacillus stearothermophilus strains that were susceptible to multiple antibacterial drug residues, and the Saccharomyces cerevisiae yeast that was susceptible to multiple toxic compounds, were employed as sensitive cells. The analyte considered for indirectly measuring antimicrobial inhibition by toxic agents was carbon dioxide (CO₂). The electrical signal detected is related to the amount of CO₂ developed during bacterial respiration. The methodological approach compared to older screening methods, also inhibition based, offers the advantages of (i) low cost; (ii) shorter analysis time; (iii) smaller sample amount; (iv) no sample treatment; (v) good precision; and (vi) the possibility of following, in a continuous manner, the inhibition process.

Keywords:

• Electrochemical sensor
• Antimicrobial drug residues
• Heavy metals
• Food analysis