Rapid Detection of Kernel Rots and Mycotoxins in Maize by Near-Infrared Reflectance Spectroscopy

Abstract

Near-infrared (NIR) spectroscopy is a practical spectroscopic procedure for the detection of organic compounds in matter. It is particularly useful because of its nondestructiveness, accuracy, rapid response, and easy operation. This work assesses the applicability of NIR for the rapid identification of micotoxigenic fungi and their toxic metabolites produced in naturally and artificially contaminated products. Two hundred and eighty maize samples were collected both from naturally contaminated maize crops grown in 16 areas in north-central Italy and from ears artificially inoculated with Fusarium verticillioides. All samples were analyzed for fungi infection, ergosterol, and fumonisin B1 content. The results obtained indicated that NIR could accurately predict the incidence of kernels infected by fungi, and by F. verticillioides in particular, as well as the quantity of ergosterol and fumonisin B1 in the meal. The statistics of the calibration and of the cross-validation for mold infection and for ergosterol and fumonisin B1 contents were significant. The best predictive ability for the percentage of global fungal infection and F. verticillioides was obtained using a calibration model utilizing maize kernels (r2 = 0.75 and SECV = 7.43) and maize meals (r2 = 0.79 and SECV = 10.95), respectively. This predictive performance was confirmed by the scatter plot of measured F. verticillioides infection versus NIR-predicted values in maize kernel samples (r2 = 0.80). The NIR methodology can be applied for monitoring mold contamination in postharvest maize, in particular F. verticilliodes and fumonisin presence, to distinguish contaminated lots from clean ones, and to avoid cross-contamination with other material during storage and may become a powerful tool for monitoring the safety of the food supply.

A Review of Optical Nondestructive Visual and Near-Infrared Methods for Food Quality and Safety

“…This assumption has been shown to be valid, for example, by Pearson and Wicklow [85] who detected the fungi in corn kernels, Gordon et al [86] for food grain, and Berardo et al [87] for maize.…”

“…Berardo et al [87] applied NIR for the detection and identification of mycotoxigenic fungi and their toxic metabolites. They analyzed the samples for fungi infection, ergosterol, and fumonisin B 1 content.…”

Spectroscopic Techniques for Nondestructive Detection of Fungi and Mycotoxins in Agricultural Materials: A Review

“…In particular, NIRS has been widely used in combination with multivariate statistical methods. Berardo et al (2005) have measured fungal infections, focusing on the development of fumonisin B 1 and ergosterol using NIRS. Sirisomboon et al (2013) have applied NIRS (950~1,650 nm) to the detection of aflatoxigenic fungal infections in rice.…”

Determination of oleic acid in the samples of sunflower seeds by method of nir-spectroscopy

“…Modern methods for quantitative analysis of free carboxylic acids in fats and oils are based on chemical transformations, are relatively long, conducted in special laboratories and require the use of chemical reagents. .The purpose of these studies was the development of an express method for the quantitative determination of oleic acid in samples of fatcontaining raw materials on the basis of diffuse reflection spectroscopy in the near IR region [5].…”