Improving Food Safety by Using One- and Two-Photon- Induced Fluorescence Spectroscopy for the Detection of Mycotoxins

Abstract

The presence of mycotoxins in food products is a major worldwide problem. Nowadays, mycotoxins can only be detected by the use of sample-based chemical analyses. Therefore, we demonstrate the use of one-and two-photon-induced fluorescence spectroscopy for the non-destructive detection of mycotoxins in unprocessed food products. We first explain our optical set-up, which is able to measure the localized oneand two-photon-induced fluorescence spectra. Following, as a case study, the detection of aflatoxin in maize kernels is discussed. We present our research methodology, from the characterization of the fluorescence of pure aflatoxin, to the study of the one-and two-photon-induced fluorescence spectra of maize kernels and the development of an optical detection criterion. During both one-and two-photon-induced fluorescence processes, the fluorescence of the aflatoxin influences the intrinsic fluorescence of the maize. Based on the fluorescence spectrum between 400 and 550 nm, a detection criterion to sense the contaminated kernels is defined. Furthermore, we successfully monitored the localized contamination level on the kernel's surface, showing both contaminated kernels with a high contamination in a limited surface area (a few square millimetres) and kernels with a low contamination spread over a large surface area (up to 20 mm 2 ). Finally, the extensibility of our research methodology to other fluorescent mycotoxins is discussed.

Selecting optimal spectral bands for improved detection of autofluorescent biomarkers in multiphoton microscopy

“…This holds especially true in scenarios where SNR is not a limiting factor or can be retrieved by higher excitation powers, as this may be the case for low-bleaching samples outside of a clinical context such as the detection of toxins in food safety. 28 Counterintuitively, in the particular case of measurements on NAD(P)H and FAD in solution, the achieved separation with the filters proposed in the literature is further away from the optimum than for the cell models. A possible explanation is that in complex tissue environments other fluorophores may significantly influence the autofluorescence spectrum and external influences may alter the individual TPEF spectra.…”

“…This holds especially true in scenarios where SNR is not a limiting factor or can be retrieved by higher excitation powers, as this may be the case for low-bleaching samples outside of a clinical context such as the detection of toxins in food safety. 28 …”