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Biomedical Sensing Applications of Microspherical Resonators
Published in Giancarlo C. Righini, Glass Micro- and Nanospheres, 2019
Silvia Soria, Simone Berneschi, Andrea Barucci, Alessandro Cosci, Daniele Farnesi, Gualtiero Nunzi Conti, Stefano Pelli, Giancarlo C. Righini
Aflatoxin M1 (AFM1) is a milk contaminant and potent carcinogen, which is regulated by the European Commission (EC No. 1881/2006) limiting the maximum allowable concentration of aflatoxin in milk products to 50 ng/kg. Thus, aflatoxin contamination represents a hazard for human health and an economic loss for the dairy industry. At present, the screening procedure involves enzyme-linked immunosorbent assay (ELISA) tests, and the suspicious samples need further investigations with high-performance liquid chromatography (HPLC) tests [51], which are costly and time-consuming processes. The WGMR approach was based on the use of a ring resonator, functionalized by using a wet silanization process and a DNA aptamer that recognizes AFM1 with high affinity and specificity. The preliminary tests demonstrated the selective binding at different aflatoxin concentrations, as well as a very good regeneration efficacy when using a glycine solution (100 mM glycine-HCl, pH 2) [36].
Nanosensors for Food Contaminant Detection
Published in C. Anandharamakrishnan, S. Parthasarathi, Food Nanotechnology, 2019
Heera Jayan, L. Bhavani Devi, C. Anandharamakrishnan
Naturally occurring chemicals involves plant, animal, or micro-organism derived substances which are naturally present in the food material. Histamine is a toxin, which is produced by spoilage bacteria in fish products. The consumption of histamine leads to skin irritation, localized inflammation, and hypertension (Arnold and Brown, 1978). Aflatoxin is a major toxin found in certain food products including corn and nuts. It is produced by Aspergillus flavus and Aspergillus parasiticus, which cause liver, kidney, and spleen enlargement, and fatty liver syndrome (Eaton and Groopman, 2013). Similarly, certain hazardous compounds are formed during the processing of food products due to chemical reactions. During thermal treatment of certain food products containing asparagine, a potential cancer-causing agent called acrylamide is released (Stadler et al., 2002).
Nanosensors for the Food Industry
Published in V. Chelladurai, Digvir S. Jayas, Nanoscience and Nanotechnology in Foods and Beverages, 2018
V. Chelladurai, Digvir S. Jayas
Mycotoxins are the toxic substances produced by secondary metabolism of fungal species (mainly Aspergillus and Penicillium) in grain and food samples. Some of the mycotoxins can cause serious health problems because these are mutagenic (can cause genetic problems), carcinogenic (can cause cancer), and teratogenic (can cause developmental problems) in nature. Aflatoxin and ochratoxin A are the most common mycotoxins produced by fungi in food and grain products. Rapid and early detection of mycotoxin will help to reduce potential health and recall issues for consumers and food producers, respectively. Immunoassay methods (ELISA test) and HPLC are the most commonly used techniques to detect aflatoxin and ochratoxin in food. Scientists across the world are developing nanotechnology-based sensors for accurate detection of mycotoxins from food samples quickly.
Optical approaches for the simple and sensitive detection of aflatoxin B1 via a liquid crystal aptasensor
Published in Liquid Crystals, 2023
Xin Yang, Xinyue Li, Junyang Jin, Junchi Ma, Jinghua Liu, Zongfu An
Finally, we analysed whether the developed sensor can be used in food samples. We added aflatoxins at concentrations of 1 nM, 1pM, and 1fM to corn and rice that were negative for aflatoxin. After mixing by grinding, we extracted the mixture. The optical response of the sensor is shown in Figure 7. At the concentrations of 1 nM and 1pM, the extracts of corn and rice samples both showed positive results (bright patterns, Figure 7(a–e)), and at the doping concentration of 1fM, they showed negative results (dark patterns, Figure 7(c,f)). This sensitivity was much lower than the US Food and Drug Administration (FDA) tolerance level of aflatoxin in human food (20 μg kg−1) [38]. The result proved that the developed sensor is useful in detecting aflatoxin in actual samples.
Determinants of aflatoxin exposures in Kenyan School-aged children
Published in International Journal of Environmental Health Research, 2022
Ruth Nabwire Wangia-Dixon, Trang Ho Thu Quach, Xiao Song, James Ombaka, David Peter Githanga, Omu Aggrey Anzala, Jia-Sheng Wang
Aflatoxins are a group of naturally occurring food contaminants produced by the soil-borne aspergillus spp fungi mainly Aspergillus flavus and Aspergillus parasiticus (IARC 2002; CAST 2003). Aflatoxins contaminate a variety of food crops including cereals, legumes, oilseeds, nuts, spices, coffee and tea (Bandyopadhyay et al. 2007; CAST 2003). Even though aflatoxin producing Aspergillus species occur worldwide, a higher prevalence in Sub-Saharan Africa and southeast Asia is evident due to hot humid climates and suboptimal control strategies (IARC 2002; Okoth 2016). Aflatoxin contamination presents a persistent challenge to food safety. Contamination can occur at every stage of the food supply chain including drying, during transport, in poor storage conditions, and in the market (Kang’ethe et al. 2017; Dembedza et al. 2019). Overall, more than 25% of the world’s food supply is estimated to be contaminated by aflatoxins (Williams et al. 2004; Smith et al. 2015). Worldwide, estimated 4.5 billion people are susceptible to aflatoxin exposures through dietary sources or in occupational settings such as grain handling. Furthermore, dietary exposure or inhalation presents significant risks to human health.
18S rRNA gene sequencing for environmental aflatoxigenic fungi and risk of hepatic carcinoma among exposed workers
Published in Journal of Environmental Science and Health, Part A, 2022
Amal Saad-Hussein, Kawther M. Soliman, Gehan Moubarz
Spore suspensions of the studied isolates were prepared and adjusted to approximately 106 spores/ml using a hemocytometer. Then 1 ml spore suspension was inoculated into 100 ml of sterile YES extract (YES; 2% yeast extract and 20% sucrose), and incubated at 28 ± 3 °C for 14 d. The entire culture filtered using Whatman filter paper No.3, the filtrate was transferred to separating funnel and extracted with chloroform (50 mlx3).[25,26] The chloroform extract was evaporated to dryness and re-dissolved in 1 ml chloroform. Aflatoxins were qualitatively detected by thin layer chromatography (TLC, 20 cm × 20 cm). Furthermore, 10 µl of the extracts and standard aflatoxins (Sigma CO) were spotted on TLC. The spotted plates were developed in the developing system (toluene: ethyl acetate: formic acid, 6:3:1, v/v/v), and examined under long wave UV light (365 nm).[27] Sample aliquot was compared with aflatoxin standards for blue AFB fluorescent spots and Rf similar to those in standards.