Electronic nose for detecting Colletotrichum coccodes causing anthracnose fruit rots in tomatoes

Abstract

Electronic nose (EN) technology has several applications targeting various study areas, and food spoilage is one of these sections. This study investigated the ability of the EN, with metal-oxide sensors (MOS), to sense the presence of Colletotrichum coccodes, which cause anthracnose fruit rots, on tomato fruit and to distinguish between different stages and doses of infection. C. coccodes were identified by an appropriate polymerase chain reaction (PCR) program and sequencing, using two different primer sets: ITS1F/ITS4 and Cc1F1/Cc2R1. Three intact homogeneous tomato samples were injected with three different concentrations of conidial fungal suspension: 3 × 104, 3 × 105 and 3 × 106 conidia/ml, and three others were kept as negative controls. Principal component analysis (PCA) was used in analyzing the data acquired from the EN sensors. The results of PCA showed that EN was able to detect the presence of C. coccodes pathogen at early stages (two days of infection and before any symptoms appear). Moreover, EN was able to differentiate between different infection stages. In addition, the concentrations of infected samples on the sixth, eighth and tenth days were clearly differentiated. The use of EN is a promising technique for determining quality assurance and control.

Keywords

• Electronic nose
• Metal-oxide sensors (MOS)
• Colletotrichum coccodes
• Anthracnose fruit rots
• Principal component analysis (PCA)