Analysis of Mycotoxins in Beer Using a Portable ... - ACS Publications

Oct 6, 2016 - (OTA) in beer using a portable nanostructured imaging surface plasmon .... (Waters, Etten-Leur, The Netherlands) were used for enrichmen...
0 downloads 0 Views 1MB Size
Subscriber access provided by CORNELL UNIVERSITY LIBRARY

Article

Analysis of Mycotoxins in Beer Using a Portable Nanostructured Imaging Surface Plasmon Resonance Biosensor Sweccha Joshi, Rumaisha M Annida, Han Zuilhof, Teris A. van Beek, and Michel W.F. Nielen J. Agric. Food Chem., Just Accepted Manuscript • DOI: 10.1021/acs.jafc.6b04106 • Publication Date (Web): 06 Oct 2016 Downloaded from http://pubs.acs.org on October 6, 2016

Just Accepted “Just Accepted” manuscripts have been peer-reviewed and accepted for publication. They are posted online prior to technical editing, formatting for publication and author proofing. The American Chemical Society provides “Just Accepted” as a free service to the research community to expedite the dissemination of scientific material as soon as possible after acceptance. “Just Accepted” manuscripts appear in full in PDF format accompanied by an HTML abstract. “Just Accepted” manuscripts have been fully peer reviewed, but should not be considered the official version of record. They are accessible to all readers and citable by the Digital Object Identifier (DOI®). “Just Accepted” is an optional service offered to authors. Therefore, the “Just Accepted” Web site may not include all articles that will be published in the journal. After a manuscript is technically edited and formatted, it will be removed from the “Just Accepted” Web site and published as an ASAP article. Note that technical editing may introduce minor changes to the manuscript text and/or graphics which could affect content, and all legal disclaimers and ethical guidelines that apply to the journal pertain. ACS cannot be held responsible for errors or consequences arising from the use of information contained in these “Just Accepted” manuscripts.

Journal of Agricultural and Food Chemistry is published by the American Chemical Society. 1155 Sixteenth Street N.W., Washington, DC 20036 Published by American Chemical Society. Copyright © American Chemical Society. However, no copyright claim is made to original U.S. Government works, or works produced by employees of any Commonwealth realm Crown government in the course of their duties.

Page 1 of 34

Journal of Agricultural and Food Chemistry

1

Analysis of Mycotoxins in Beer Using a Portable Nanostructured

2

Imaging Surface Plasmon Resonance Biosensor Sweccha Joshi, †, ‡ Rumaisha M. Annida, † Han Zuilhof, † Teris A. van Beek, †* Michel W.F. Nielen†,§

3 4 5



6

Wageningen, The Netherlands

7



TI-COAST, Science Park 904, 1098 XH Amsterdam, The Netherlands

8

§

RIKILT Wageningen University & Research, P.O. Box 230, 6700 AE Wageningen, The

9

Netherlands

Laboratory of Organic Chemistry, Wageningen University, Stippeneng 4, 6708 WE

10

*

11

[email protected]

Corresponding author (Tel:+31 317 482376; Fax: +31 317 484914; E-mail:

12

1 ACS Paragon Plus Environment

Journal of Agricultural and Food Chemistry

Page 2 of 34

13

ABSTRACT: A competitive inhibition immunoassay is described for the mycotoxins

14

deoxynivalenol (DON) and ochratoxin A (OTA) in beer using a portable nanostructured

15

imaging surface plasmon resonance (iSPR) biosensor, also referred to as imaging

16

nanoplasmonics. The toxins were directly and covalently immobilized on a 3-dimensional

17

carboxymethylated dextran (CMD) layer on a nanostructured iSPR chip. The assay is based

18

on competition between the immobilized mycotoxins and free mycotoxins in the solution for

19

binding to specific antibodies. The chip surface was regenerated after each cycle and the

20

combination of CMD and direct immobilization of toxins allowed the chips to be used for

21

more than 450 cycles. The limits of detection (LODs) in beer were 17 ng/mL for DON and 7

22

ng/mL for OTA (or 0.09 ng/mL after 75 times enrichment). These LODs allowed detection of

23

even less than 10% depletion of the tolerable daily intake of DON and OTA by beer.

24

Significant cross-reactivity of anti-DON was observed towards DON-3-glucoside and 3-

25

acetyl-DON while no cross-reactivity was seen for 15-acetyl-DON. A preliminary in-house

26

validation with 20 different batches of beer showed that both toxins can be detected at the

27

considered theoretical safe level for beer. The assay can be used for in-field or at-line

28

detection of DON in beer and also in barley without pre-concentration, while OTA in beer

29

requires an additional enrichment step thus making the latter in its present form less suitable

30

for field applications.

31 32

KEYWORDS: Imaging SPR, mycotoxins, beer, nanoplasmonics, deoxynivalenol, ochratoxin

33

A

2 ACS Paragon Plus Environment

Page 3 of 34

Journal of Agricultural and Food Chemistry

34

INTRODUCTION

35

Mycotoxins are the secondary metabolites of fungi commonly found in several foods,

36

beverages, and animal feed and are known to be teratogenic, mutagenic, and carcinogenic.1

37

They are carried-over from infected barley into malt and ultimately to beer due to their

38

thermal stability and relatively good water solubility.2-4 Therefore, careful screening of beer

39

ingredients and end products is required for safety of the consumers. The occurrence of

40

different mycotoxins in beer has been reported earlier with most studies focusing on

41

deoxynivalenol 1 (DON) mainly due to its high incidence.5,6 Another mycotoxin, ochratoxin

42

A 5 (OTA), although detected in beer at low concentrations (only