Estefania Nunez Carmona

Detection of microorganisms in water and different food matrix by Electronic Nose

In the food matrix are involved very elemental products like water to other more complex like, for example, processed and non processed, vegetables and dairy products. All these matrix pass very restrictive controls and a intensive monitoring during the processing time to evaluate their safety and quality. The early detection of the contamination is critical to preserve the consumers health and to avoid economic losses for the industry. On the other hand, microorganisms are part of a wide range and significant managing process, like fermentations used since ancient times and applied to many different matrix. One of this group of microorganism are Lactic Acid Bacteria (LAB) that play a different role, fermentative or contaminant, depending on the matrix where are founded. Electronic Noses (ENs) has shown to be a very effective and fast tool for monitoring microbiological spoilage and food quality control. The ability of this instrument can also be used for the selection of the most appropriate species or strains for a determinate purpose. The aim of this study was essay the ability of a novel EN for the detection of bacterial presence in water and other foodstuff in cooperation with classical microbiological and chemical techniques like Gas Chromatography Mass Spectrometry with SPME (GC-MS-SPME). The achieved results notably advocate the use of EN in industry laboratories like a very important tool in quality control.

A Novel MOS Nanowire Gas Sensor Device (S3) and GC-MS-Based Approach for the Characterization of Grated Parmigiano Reggiano Cheese

To determine the originality of a typical Italian Parmigiano Reggiano cheese, it is crucial to define and characterize its quality, ripening period, and geographical origin. Different analytical techniques have been applied aimed at studying the organoleptic and characteristic volatile organic compounds (VOCs) profile of this cheese. However, most of the classical methods are time consuming and costly. The aim of this work was to illustrate a new simple, portable, fast, reliable, non-destructive, and economic sensor device S3 based on an array of six metal oxide semiconductor nanowire gas sensors to assess and discriminate the quality ranking of grated Parmigiano Reggiano cheese samples and to identify the VOC biomarkers using a headspace SPME-GC-MS. The device could clearly differentiate cheese samples varying in quality and ripening time when the results were analyzed by multivariate statistical analysis involving principal component analysis (PCA). Similarly, the volatile constituents of Parmigiano Reggiano identified were consistent with the compounds intimated in the literature. The obtained results show the applicability of an S3 device combined with SPME-GC-MS and sensory evaluation for a fast and high-sensitivity analysis of VOCs in Parmigiano Reggiano cheese and for the quality control of this class of cheese.

Real-Time Microwave, Dielectric, and Optical Sensing of Lincomycin and Tylosin Antibiotics in Water: Sensor Fusion for Environmental Safety

Antibiotics are widely used to prevent and treat bacterial infections in livestock animals, aquaculture, and humans. However, the unconditional use of those drugs as a growth promoter for livestock animals and the wrong usage as a treatment for infections in humans has led to high antibiotics pollution, especially in water resources. The elevated presence of antibiotics in water has resulted in the phenomenon known as the bacterial antibiotics resistance. To prevent ecological catastrophe, continuous real-time monitoring of water sources is necessary. The aim of this research work is to compare the abilities of three different techniques: novel electromagnetic wave spectroscopy, UV-Vis spectrophotometry, and capacitance sensing system for the real-time detection and quantification of antibiotics in water. Tylosin and lincomycin antibiotics were selected to the study, as both are regularly found in water sources. Two novel microwave sensor configurations were used: a planar sensor with interdigitated electrode pattern and a hairpin resonator sensor, as a means of real-time water analysis. Reflected S11 power signals were analyzed in GHz frequency range for microwave sensors. In parallel, UV-Vis spectrophotometry was used, where change in the optical absorbance was used as an indicator of water pollution, whereas change in the value of a capacitance in low frequency range has signalled the change in the dielectric properties of the solution. It was found that in all cases the changes in the measured parameters were dependent on both the type of antibiotic present in water and on its concentration. Fusion of all these techniques into a comprehensive sensing platform provides adequate real-time assessment of the water pollution with antibiotics and would allow adequate management of environment for safety and sustainable development. In particular, the lowest lincomycin samples’ concentration, 0.25 μg/l, was measured with a hairpin resonator sensor, while the lowest tylosin samples’ concentration, 0.20 μg/l, was measured with an IDE sensor. Since concentration in groundwater were 0.36 μg/l of lincomycin and 1.5 μg/l of tylosin, it is demonstrating a high-sensing platform utility.

Nanowire (S3) Device for the Quality Control of Drinking Water

The control and sanitation of water it’s a worldwide concerning problem. In particular is in developing countries where the need is more evident due to the lack of sources and appropriate structures to cope with the outbreaks of waterborne diseases. In most of cases, the cause of these significant epidemiological events have microbial origin. Despite of it the situation of water supplies and sanitation has improve all over the world in the last decades. Nanowire technology has already shown their ability to perform very effective and fast monitoring microbiological spoilage and quality control. The aim of this study was to test the ability of a novel S3 (Small Sensor System) nanowire device for the detection of complex mixtures of bacteria in potable water in order to approach into a real condition, in cooperation with GC-MS- SPME technique. The achieved results notably advocate the use of EN as a very easy to use, fast and accurate tool in water quality control.

Grated Parmigiano Reggiano Cheese: Authenticity Determination and Characterization by a Novel Nanowire Device (S3) and GC-MS

Parmigiano Reggiano (PR) cheese is produced from the bovine milk in a limited geographic area in northern Italy. It is one of the oldest traditional cheeses manufactured in Europe (XII century) and is still one of the most esteemed Protected Designation of Origin (PDO) cheeses of Italy. The Parmigiano Reggiano Cheese Consortium (CFPR) is the institutional system that covers all the cheese dairy factories and controls the cheese production in terms of cow feeding, cheese manufacture and ripening processes. The aim of this study was to establish a new, rapid, portable, easy-to-use, economic and non-destructive fouling based on nanowire technology device (S3) to control the presence of false grated PR. All the analyzed samples were collected from the Consortium that picked the samples produced in different European countries (three samples from Germany, one from Ireland, one from Latvia and one from Lithuania). The achieved samples were analyzed with the cooperation of multidisciplinary technologies like Colorimeter, pH Meter, GC-MS with SPME and the new nanowire gas sensor device (S3). The applied techniques were able to create a specific database for the S3 device, capable to give results in a few minutes. The use of a Small Sensor System (S3) device to determine the specific volatile organic compounds (VOCs) of the grated PR is a promising approach offering, at the same time, a simpler, faster and easier to handle (no specialized technicians are required) solution with respect to the analytical techniques (GC-MS, HPLC). However, from the commercial point-of-view, low cost and reduced power consumption are the fundamental features that should entail a sensor device. In this study, S3 device was applied and found to be efficient in the discrimination of the different grated PR cheese samples. In particular, the discrimination was checked quali-quantitatively thanks to the analysis performed with the GC-MS-SPME technique. In fact, the achieved results demonstrated the quali-quantitative differences of the VOCs emitted by the samples. S3 device is a promising tool for the quality discrimination of the PR cheese and other foodstuffs. In our future works, specific database of the grated PR will be amplified for the direct use of S3 in the cheese-chain productions.

Nanowire Technology to Asses the Bacterial Presence in Water and other Food Stuff

It has been broadly documented the presence of bacteria, yeast and mold in food processing like fermentations, ripening and also spoiling. The early detection of the contamination is critical to preserve the consumer’s health and to avoid economic losses for the industry. The aim of this work was the establish a new fouling based on the cooperation between the use of a novel EN and classical techniques, like GC-MS coupled with classical microbiology, for the detection of bacterial presence in water and other foodstuff.