A label free aptasensor for Ochratoxin A detection in cocoa beans: An
Rupesh K. Mishra a, Akhtar Haya a, * , 52 Ave al Mater
Label free 0.15e2.5 ng/mL, with an acceptable recovery percentage (91e95%, RSD ¼ 4.8%) obtained in cocoa beans based on the ucted and aptamer . All rights reserved.
Food contamination is one of the most important worldwide issues and has been paid much attentionwith the fast development of economics and improvement of human life. Among all, nch. Ochratoxin A (OTA) is frequently presents in various agricultural commodities during storage . OTA is the most toxic and known to be hepatotoxic, nephrotoxic, teratogenic andmutagenic to awide variety of mammalian species [2,3]. Thus, it is characterized as possibly carcinogenic to humans (Group 2B, according to the IARC classification) . It occurs naturally in a wide variety of raw commodities and finished food products of vegetal origin such as cereals, coffee beans, pulses, and dried fruits as well as cocoa derived products.
Cocoa is a cash crop produced in many countries of the world with * Corresponding author. UPVD, IMAGES EA 4218, Bat S, 52, Avenue Paul Alduy, 66860 Perpignan Cedex, France.
Contents lists availab
Analytica Ch w.e
Analytica Chimica Acta 889 (2015) 106e112E-mail address: firstname.lastname@example.org (J.-L. Marty).Impedimetric
Screen printed electrodes samples. This work can facilitate a general model for the detection of OTA in cocoa impedimetric aptasensor. The analysis can be performed onsite with pre-constr modified electrodes employing a portable EIS set up. © 2015 Elsevier B.V 1. Introduction contamination by toxins is one important braAptasensor
Cocoa beans increase in electron transfer resistance was linearly proportional to the OTA concentration in the rangeKeywords:http://dx.doi.org/10.1016/j.aca.2015.06.052 0003-2670/© 2015 Elsevier B.V. All rights reserved.aptamer on screen printed carbon electrodes (SPCEs). The aptasensor exhibited a very good limit of detection (LOD) as low as 0.15 ng/mL, with added advantages of good selectivity and reproducibility. Thea r t i c l e i n f o
Received 26 January 2015
Received in revised form 26 June 2015
Accepted 27 June 2015
Available online 10 August 2015a b s t r a c t
Contamination of food by mycotoxin occurs in minute/trace quantities. Nearly 92.5% of the cocoa samples present Ochratoxin A (OTA) levels at trace quantity. Hence, there is a necessity for a highly sensitive and selective device that can detect and quantify these organic toxins in various matrices such as cocoa beans. This work reports for the first time, a facile and label-free electrochemical impedimetric aptasensor for rapid detection and quantitation of OTA in cocoa beans. The developed aptasensor was constructed based on the diazonium-coupling reaction mechanism for the immobilization of anti-OTA-Jean-Louis Marty a IMAGES, Universite De Perpignan Via Domitia b Interdisciplinary Research Centre in Biomedic h i g h l i g h t s Simple and facile method to detect
OTA. The aptasensor exhibited a very good limit of detection (LOD) as low as 0.15 ng/mL. The first report on OTA detection in cocoa beans using impedimetric aptasensor.t a, b, Ga€elle Catanante a, Cristina Oca~na a, nue Paul Alduy, Perpignan Cedex 66860, France ials (IRCBM), COMSATS Institute of Information Technology (CIIT), Lahore 54000, Pakistan g r a p h i c a l a b s t r a c tapplication to chocolate industriesjournal homepage: wwle at ScienceDirect imica Acta lsevier .com/locate/aca himabout 71% of the world production from West African countries especially from the Ivory Coast (30% of the world's production), but also from Ghana and Nigeria. Cocoa is also produced in Asia (15.8%) and Latin America (12.4%) . Cocoa beans after post-harvest treatments are mainly exported to Europe and North America to be turned into liquor, butter and cocoa powder . Cocoa and various derivatives contamination (International Cocoa Organization [ICCO]) with OTA has been revealed by numerous studies using conventional techniques [5,7,8].
The health risks associated with the consumption of OTAcontaminated foods necessitates drastic measures to protect worldwide consumer health. Accordingly, in the European market, food products are subject to maximum allowable threshold concentrations of OTA. The EU 1881/2006 regulation sets maximum levels of OTA in foodstuffs: 5 mg/kg in cereals, 3 mg/kg in cerealprocessed products, and 2 mg/kg in cocoa, wine and spices .
The Superior Council for Public Hygiene of France (Conseil
Superieur de l'Hygiene Publique de France [CSHPF], 1999) and the
Scientific Committee on Food (Scientific Committee on Food [SCF], 1998) established a tolerable daily intake (TDI) of 5 ng/kg body weight/day based upon data from “in vivo” experiments accounting for nephrotoxicity in rats.
However, with the maximum admissible value of OTA established in 2 mg/kg, about 40% of the cocoa which arrives in Europe may be rejected at the ports . Despite the fact that cocoa beans are not ingested raw, and most of OTA (80%) are in the shells, cocoa processing does not always completely eliminate the toxin [6,11].
Thus, beans and cocoa derivatives can only be exported if there are well-established quality criteria, including the analysis of OTA occurrence.
The clearly undesirable presence of trace amounts of OTA in foodstuffs requires suitable sampling procedures and highly sensitive techniques to detect and control OTA concentrations at trace level . Apart from precision and accuracy, the wide varieties of matrices where OTA can be found pose a great challenge to analytical scientists. Furthermore, the presence of several mycotoxins in a same sample may produce synergistic effects, what firmly encourages researchers to search for analytical techniques able to perform highly selective measurements [13e15]. High performance liquid chromatography (HPLC) with fluorescence detectors have been widely adopted as the standard methods for OTA detection [16,17]. In addition, gas chromatography-mass spectrometry, thin layer chromatography (TLC) and enzyme linked immunosorbent assay (ELISA) also showed good performance for