Screening for malachite green contamination on live fish skin with chewing gum based viscoelastic SERS sensor

Wan-Li Fan ^a,1, Shi-Wei Yang ^b,1, Dong-Mei Wang ^a,*, Zheng-Jun Gong ^a, Mei-Kun Fan ^a,b,**

a Faculty of Geosciences and Environmental Engineering, Southwest Jiaotong University, Chengdu, Sichuan 610031, China

b School of Civil Engineering, Southwest Jiaotong University, Chengdu, Sichuan 610031, China

Malachite green (MG), a prohibited but still found antimicrobial in aquafarm and during live fish shipping, is a hot target in food safety screening. Herein, a novel chewing gum based flexible SERS (G-SERS) sensor was proposed for rapid sampling and detection of MG on live fish skin. The whole analysis takesmin, while the limit of detection for MG is 0.73 pg. Different from other reports, MG contaminated live fish was monitored daily with the G-SERS sensor, during which the fish was firstly raised in 0.5 ppm MG solution for one day, followed by freshwater for a week. It was found that the SERS signal of residue MG on fish skin could still be seen even on the sixth day, roughly the sale cycle of live fish in a marketplace. Furthermore, the method was also applied for MG screening on the skin of fish purchased from a supermarket and a local street marketplace. MG was found on some fishes from the latter but not from the former, which was cross-validated by LC-MS, suggesting MG risks still exist in smaller marketplaces. This work demonstrated the feasibility of using the flexible SERS sensor for onsite food safety screening.

Keywords: Food safety monitoring, Malachite green, Live fish, SERS, Gum

https://doi.org/10.38212/2224-6614.1057

(https://www.jfda-online.com/journal/vol28/iss2/4/)