This work investigates non-contact reflectance spectral imaging techniques, i.e. microscopic Four... more This work investigates non-contact reflectance spectral imaging techniques, i.e. microscopic Fourier transform infrared (FTIR) imaging, macroscopic visible-near infrared (VNIR), and shortwave infrared (SWIR) spectral imaging, for the identification of bacteria on stainless steel. Spectral images of two Gram-positive (GP) bacteria (Bacillus subtilis (BS) and Lactobacillus plantarum (LP)), and three Gram-negative (GN) bacteria (Escherichia coli (EC), Cronobacter sakazakii (CS), and Pseudomonas fluorescens (PF)), were collected from dried suspensions of bacterial cells dropped onto stainless steel surfaces. Through the use of multiple independent biological replicates for model validation and testing, FTIR reflectance spectral imaging was found to provide excellent GP/GN classification accuracy (> 96%), while the fused VNIR-SWIR data yielded classification accuracy exceeding 80% when applied to the independent test sets. However, classification within gram type was far less reliable...
This work investigates the application of reflectance Fourier transform infrared (FTIR) microscop... more This work investigates the application of reflectance Fourier transform infrared (FTIR) microscopic imaging for rapid, and non-invasive detection and classification between Bacillus subtilis and Escherichia coli cell suspensions dried onto metallic substrates (stainless steel (STS) and aluminium (Al) slides) in the optical density (OD) concentration range of 0.001 to 10. Results showed that reflectance FTIR of samples with OD lower than 0.1 did not present an acceptable spectral signal to enable classification. Two modelling strategies were devised to evaluate model performance, transferability and consistency among concentration levels. Modelling strategy 1 involves training the model with half of the sample set, consisting of all concentrations, and applying it to the remaining half. Using this approach, for the STS substrate, the best model was achieved using support vector machine (SVM) classification, providing an accuracy of 96% and Matthews correlation coefficient (MCC) of 0....
Cold plasma technology is an efficient, environmental‐friendly, economic and noninvasive technolo... more Cold plasma technology is an efficient, environmental‐friendly, economic and noninvasive technology; and in recent years these advantages placed this novel technology at the centre of diverse studies for food industry applications. Dried food ingredients including spices, herbs, powders and seeds are an important part of the human diet; and the growing demands of consumers for higher quality and safe food products have led to increased research into alternative decontamination methods. Numerous studies have investigated the effect of nonthermal plasma on dried food ingredients for food safety and quality purposes. This review provides critical review on potential of cold plasma for disinfection of dried food surfaces (spices, herbs and seeds), improvement of functional and rheological properties of dried ingredients (powders, proteins and starches). The review further highlights the benefits of plasma treatment for enhancement of seeds performance and germination yield which could be applied in agricultural sector in near future. Different studies applying plasma technology for control of pathogens and spoilage micro‐organisms and modification of food quality and germination of dried food products followed by benefits and current challenges are presented. However, more systemic research needs to be addressed for successful adoption of this technology in food industry.
This work investigates non-contact reflectance spectral imaging techniques, i.e. microscopic Four... more This work investigates non-contact reflectance spectral imaging techniques, i.e. microscopic Fourier transform infrared (FTIR) imaging, macroscopic visible-near infrared (VNIR), and shortwave infrared (SWIR) spectral imaging, for the identification of bacteria on stainless steel. Spectral images of two Gram-positive (GP) bacteria (Bacillus subtilis (BS) and Lactobacillus plantarum (LP)), and three Gram-negative (GN) bacteria (Escherichia coli (EC), Cronobacter sakazakii (CS), and Pseudomonas fluorescens (PF)), were collected from dried suspensions of bacterial cells dropped onto stainless steel surfaces. Through the use of multiple independent biological replicates for model validation and testing, FTIR reflectance spectral imaging was found to provide excellent GP/GN classification accuracy (> 96%), while the fused VNIR-SWIR data yielded classification accuracy exceeding 80% when applied to the independent test sets. However, classification within gram type was far less reliable...
This work investigates the application of reflectance Fourier transform infrared (FTIR) microscop... more This work investigates the application of reflectance Fourier transform infrared (FTIR) microscopic imaging for rapid, and non-invasive detection and classification between Bacillus subtilis and Escherichia coli cell suspensions dried onto metallic substrates (stainless steel (STS) and aluminium (Al) slides) in the optical density (OD) concentration range of 0.001 to 10. Results showed that reflectance FTIR of samples with OD lower than 0.1 did not present an acceptable spectral signal to enable classification. Two modelling strategies were devised to evaluate model performance, transferability and consistency among concentration levels. Modelling strategy 1 involves training the model with half of the sample set, consisting of all concentrations, and applying it to the remaining half. Using this approach, for the STS substrate, the best model was achieved using support vector machine (SVM) classification, providing an accuracy of 96% and Matthews correlation coefficient (MCC) of 0....
Cold plasma technology is an efficient, environmental‐friendly, economic and noninvasive technolo... more Cold plasma technology is an efficient, environmental‐friendly, economic and noninvasive technology; and in recent years these advantages placed this novel technology at the centre of diverse studies for food industry applications. Dried food ingredients including spices, herbs, powders and seeds are an important part of the human diet; and the growing demands of consumers for higher quality and safe food products have led to increased research into alternative decontamination methods. Numerous studies have investigated the effect of nonthermal plasma on dried food ingredients for food safety and quality purposes. This review provides critical review on potential of cold plasma for disinfection of dried food surfaces (spices, herbs and seeds), improvement of functional and rheological properties of dried ingredients (powders, proteins and starches). The review further highlights the benefits of plasma treatment for enhancement of seeds performance and germination yield which could be applied in agricultural sector in near future. Different studies applying plasma technology for control of pathogens and spoilage micro‐organisms and modification of food quality and germination of dried food products followed by benefits and current challenges are presented. However, more systemic research needs to be addressed for successful adoption of this technology in food industry.
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