Abstract
A non-invasive, small, and fast device is needed for food freshness monitoring, as current techniques do not meet these criteria. In this study, a resistive sensor composed of a single semiconductor nanowire was used at different temperatures, combining the responses and processing them with multivariate statistical analysis techniques. The sensor, very sensitive to ammonia and total volatile basic nitrogen, proved to be able to distinguish samples of fish (marble trout, Salmo trutta marmoratus) and meat (pork, Sus scrofa domesticus), both stored at room temperature and 4 °C in the refrigerator. Once separated, the fish and meat samples were classified by the degree of freshness/degradation with two different classifiers. The sensor classified the samples (trout and pork) correctly in 95.2% of cases. The degree of freshness was correctly assessed in 90.5% of cases. Considering only the errors with repercussions (when a fresh sample was evaluated as degraded, or a degraded sample was evaluated as edible) the accuracy increased to 95.2%. Considering the size (less than a square millimeter) and the speed (less than a minute), this type of sensor could be used to monitor food production and distribution chains.
Highlights
IntroductionFood safety is important nowadays, especially when it comes to fresh food
The nanowires were grown using an alumina boat filled with pure tin monoxide, placed in the center of the furnace, at its maximum temperature as the evaporation source
The temperature was increased from 26 ◦ C to 850 ◦ C at a rate of 25 ◦ C/min, and the oven was held at 850 ◦ C for five minutes
Summary
Food safety is important nowadays, especially when it comes to fresh food. Fresh foods are healthier but are more prone to rapid degradation. This has important repercussions both in terms of food losses along the distribution chain and on the health of consumers and on the health system [1,2]. The modern development of longer distribution chains is not suitable for this type of food, as it extends the time that passes before the consumer has the product at home and increases the possibility of degradation [3]. The metabolic activity of these microbes can lead to the production of ammonia, biogenic amines, nitrogen compounds, alcohols, ketones, aldehydes, esters, gases (CO2 ), etc. The metabolic activity of these microbes can lead to the production of ammonia, biogenic amines, nitrogen compounds, alcohols, ketones, aldehydes, esters, gases (CO2 ), etc. responsible for unpleasant odors [4]
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