A Multiple Approach Combined with Portable Electronic Nose for Assessment of Post-harvest Sapota Contamination by Foodborne Pathogens

Sapota (Manilkara Zapota) belongs to the Sapotaceae family and is one of the sweetest, delicious, and popular tropical fruits with high nutritional benefits. Due to its high water content (78%), it is easily damaged, which in turn reduces its shelf life. Also, significant post-harvest losses occur due to insufficient storage, poor handling, and transportation conditions, which also increase the microbial or pathogenic contamination. In this context, we have deployed an electronic nose for the first time to rapidly discriminate fresh sapota from bacterial contaminated sapota samples. The electronic nose response was varied from 0.1 to 2.9 V for sapota samples studied from day 1 to day 6. Fourier transform infrared spectra showed a gradual increase in the intensities of OH and H-O-H peaks at 3320 cm−1 and 1636 cm−1for these samples. Also, Staphylococcus bacteria were detected for the same set of sapota samples. Headspace GC-MS results of day 2, day 4, and day 6 sapota samples revealed the increasing trend in bacterial volatiles, namely ethanol, acetaldehyde, and isopropyl alcohol. The sensor data were provided as input to principal component analysis (PCA), Ward’s method analysis, and response surface methodology (RSM) for distinguishing fresh, half-contaminated, and fully contaminated sapota samples.