Food Fingerprinting: Using a Two-Tiered approach to Monitor and Mitigate Food Fraud in Rice.

BACKGROUND: Rice is an important staple food that is consumed around the world. Like many foods, the price of rice varies considerably, from very inexpensive for a low-quality product to premium pricing for highly prized varieties from specific locations. Therefore, like other foods it is vulnerable to economically motivated adulteration through substitution or misrepresentation of inferior-quality rice for more expensive varieties. OBJECTIVE: In this article we describe results of a research project focused on addressing potential food fraud issues related to rice supplies in China, India, Vietnam, and Ghana. Rice fraud manifests differently in each country; therefore, tailored solutions were required. METHOD: Here we describe a two-tiered testing regime of rapid screening using portable Near Infrared technology supported by second tier testing using mass spectrometry-based analysis of suspicious samples. RESULTS: Portable Near Infrared spectroscopy models and laboratory-based Gas Chromatography-Mass Spectrometry methods were developed to differentiate between: high-value Basmati rice varieties and their potential adulterants; six Geographic Indicated protected rice varieties from specific regions within China; various qualities of rice in Ghana and Vietnam; and locally produced and imported rice in Ghana. Furthermore, an Inductively Coupled Plasma-Mass Spectrometry method was developed to support the Chinese rice varieties methods as well as a Liquid Chromatography Quadrupole Time-of-Flight Mass Spectrometry method for quality differentiation in Vietnam. CONCLUSIONS/HIGHLIGHTS: This two-tier approach can provide a substantially increased level of testing through rapid screening outside of the laboratory with the reassurance of corroborating mass spectrometry-based laboratory analysis to support decision making.

Effect of the lactoperoxidase system against three major causal agents of disease in mangoes.

The antibacterial activity of the lactoperoxidase system (LPS) on the growth of Xanthomonas campestris, the causal agent of bacterial black spot in mangoes, Botryodiplodia theobromae, the causal agent of stem-end rot disease in mangoes, and Colletotrichum gloeosporioides, the causal agent of anthracnose disease in mangoes, was determined during culture at 30 degrees C and at several pH values (4.5, 5.5, and 6.5). When the results of using the LPS were compared with those from control cultures without the LPS reagents, the growth of the three microorganisms was totally inhibited in all of the conditions tested. Viability tests enumerating cultivable cells of X. campestris showed that the LPS had a bactericidal effect, whatever the pH value. This effect is faster at pH 5.5, corroborating the results reported in the literature (optimal pH for the LPS efficiency). Further, we proved that hydrogen peroxide alone had little inhibition effect on the growth of the microorganisms studied. This compound is essentially used to convert thiocyanate into hypothiocyanate during the lactoperoxidase reaction. The potential of the LPS for the postharvest treatment of the fruits for controlling microbial diseases was thus demonstrated. Nevertheless, further studies are needed on fresh fruits before envisaging any application.

Evaluation of lactoperoxidase system treatment to reduce anthracnose, stem-end rot, and bacterial black spot development during storage of mangoes.

The lactoperoxidase system (LPS) was evaluated for the prevention of postharvest diseases caused by Xanthomonas campestris, Botryodiplodia theobromae, and Colletotrichum gloeosporioides in 'Keitt' and 'Kent' mangoes. The LPS treatment significantly reduced the disease development on both cultivars after storage at 12 degrees C for 2 weeks, which was followed by a ripening at 25 degrees C. The LPS treatment did not alter the sensory quality of mango fruits (color, firmness, titrable acidity, and total soluble solids) when compared to untreated fruits. The LPS thus presents good potential alternative to the chemical fungicides traditionally used to improve the shelf life of mangoes.