Development of a colorimetric sensor for monitoring of fish spoilage amines in packaging headspace

Abstract

The development of an inexpensive "chemical bar-code", in the form of on-package sensor spots that monitors spoilage in fish and seafood products is being described. The sensor contains a chromoreactant dye (pH sensitive) that indicates by a visible colour change the presence of volatile spoilage compounds such as trimethylamine (TMA), ammonia (NH3) and dimethylamine (DMA) collectively known as Total Volatile Basic Nitrogen (TVB-N). Under EU directive 95/149/EEC, TVB-N analysis must be performed if sensory methods raise doubts about the freshness of seafood species. The response can be monitored with a simple, portable and inexpensive reflectance colorimeter that we have developed based on LEDs and a photodetector. The choice of LED was to match the absorption band of the chosen dye. Trials on cod, whiting and under-utilised species (Roundnose brigadier and Cardinal) enabled real time monitoring of their spoilage and the sensor responses were found to correlate to changing microbial populations.

Low-cost fiber-optic waveguide sensor for the colorimetric detection of ammonia

“…Applications fields of ammonia sensors include environmental monitoring, biomedicine, process monitoring and the control of perishable goods (Rogers and Poziomek 1996;Wolfbeis 1990;Pacquit et al 2004). The sensors do not need a high accuracy, but a compact setup, long-term stability, low energy consumption and low fabrication costs, and optionally wireless data communication.…”

Evaluation of pH indicator-based colorimetric films for ammonia detection using optical waveguides

“…A higher sensitivity, signal to noise ratio and lower LOD could certainly be obtained with a longer waveguide and a higher concentration of pH indicator. Despite its higher sensitivity to humidity, BPB + PMMA + TBP was chosen since it presented the fastest response time and the best linear response to low concentrations of NH 3 .…”

“…When the gas is sucked in the tube a color change occurs and its concentration can be evaluated with a graduation. Here, we focused on the detection of ammonia, which is produced by the putrefaction of perishable goods, for example seafood [2,3], and is present in chemical compounds such as refrigerant, explosives or fertilizers [4].…”

Optical fiber waveguide sensor for the colorimetric detection of ammonia

“…Applications fields of ammonia sensors include environmental monitoring, biomedicine, process monitoring and the control of perishable goods [1][2][3] . The sensors do not need a high accuracy, but a compact setup, long-term stability, low energy consumption and low fabrication costs, and optionally wireless data communication.…”