OCHRATOXIN A DETERMINATION IN CURED HAM BY HIGH PERFORMANCE LIQUID CHROMATOGRAPHY FLUORESCENCE DETECTION AND ULTRA PERFORMANCE LIQUID CHROMATOGRAPHY TANDEM MASS SPECTROMETRY: A COMPARATIVE STUDY

Fluorescence and absorbance dual-mode immunoassay for detecting Ochratoxin A

In this work, a simple dual-mode immunoassay for detecting Ochratoxin A (OTA) was developed by mixing G-quadruplex/N-methylmesoporphyrin IX (G4/NMM) and 3,3',5,5'-tetramethylbenzidine (TMB). The fluorescence of G4/NMM can be quenched by oxidized TMB (oxTMB) because the absorbance of oxTMB overlapped with the fluorescence emission of G4/NMM. In the absence of OTA, large amounts of oxTMB were formed with blue color and the fluorescence of G4/NMM was quenched. In the presence of OTA, the concentration of oxTMB was decreased, therefore the fluorescence of G4/NMM increased. The linear range of fluorescence immunoassay was 0.195-25 ng/mL, and the linear range of the absorbance immunoassay was 0.049-1.563 ng/mL. Thus, the linear range of this dual-mode immunoassay can be expanded to 0.049-25 ng/mL. Meanwhile, the new method showed good selectivity for OTA. Besides, the satisfactory recovery rates implied the new method had a potential value for practical sample detection.

Ochratoxin A in Slaughtered Pigs and Pork Products

Ochratoxin A (OTA) is a mycotoxin that is produced after the growth of several Aspergillus and Penicillium spp. in feeds or foods. OTA has been proved to possess nephrotoxic, hepatotoxic, teratogenic, neurotoxic, genotoxic, carcinogenic and immunotoxic effects in animals and humans. OTA has been classified as possibly carcinogenic to humans (Group 2B) by the IARC in 2016. OTA can be mainly found in animals as a result of indirect transmission from naturally contaminated feed. OTA found in feed can also contaminate pigs and produced pork products. Additionally, the presence of OTA in pork meat products could be derived from the direct growth of OTA-producing fungi or the addition of contaminated materials such as contaminated spices. Studies accomplished in various countries have revealed that pork meat and pork meat products are important sources of chronic dietary exposure to OTA in humans. Various levels of OTA have been found in pork meat from slaughtered pigs in many countries, while OTA levels were particularly high in the blood serum and kidneys of pigs. Pork products made from pig blood or organs such as the kidney or liver have been often found to becontaminated with OTA. The European Union (EU) has established maximum levels (ML) for OTA in a variety of foods since 2006, but not for meat or pork products. However, the establishement of an ML for OTA in pork meat and meat by-products is necessary to protect human health.

Risk assessment of ochratoxin A in food

The European Commission asked EFSA to update their 2006 opinion on ochratoxin A (OTA) in food. OTA is produced by fungi of the genus Aspergillus and Penicillium and found as a contaminant in various foods. OTA causes kidney toxicity in different animal species and kidney tumours in rodents. OTA is genotoxic both in vitro and in vivo; however, the mechanisms of genotoxicity are unclear. Direct and indirect genotoxic and non-genotoxic modes of action might each contribute to tumour formation. Since recent studies have raised uncertainty regarding the mode of action for kidney carcinogenicity, it is inappropriate to establish a health-based guidance value (HBGV) and a margin of exposure (MOE) approach was applied. For the characterisation of non-neoplastic effects, a BMDL 10 of 4.73 μg/kg body weight (bw) per day was calculated from kidney lesions observed in pigs. For characterisation of neoplastic effects, a BMDL 10 of 14.5 μg/kg bw per day was calculated from kidney tumours seen in rats. The estimation of chronic dietary exposure resulted in mean and 95th percentile levels ranging from 0.6 to 17.8 and from 2.4 to 51.7 ng/kg bw per day, respectively. Median OTA exposures in breastfed infants ranged from 1.7 to 2.6 ng/kg bw per day, 95th percentile exposures from 5.6 to 8.5 ng/kg bw per day in average/high breast milk consuming infants, respectively. Comparison of exposures with the BMDL 10 based on the non-neoplastic endpoint resulted in MOEs of more than 200 in most consumer groups, indicating a low health concern with the exception of MOEs for high consumers in the younger age groups, indicating a possible health concern. When compared with the BMDL 10 based on the neoplastic endpoint, MOEs were lower than 10,000 for almost all exposure scenarios, including breastfed infants. This would indicate a possible health concern if genotoxicity is direct. Uncertainty in this assessment is high and risk may be overestimated.

Determination of ochratoxin A in pork meat products: single laboratory validation method and preparation of homogeneous batch materials

Ochratoxin A is one of the most diffused mycotoxin present in a large spectrum of food commodities, mainly produced by Aspergillus ochraceus, Aspergillus carbonarius, Aspergillus niger and Penicillium verrucosum. EU has set maximum limits for a number of matrices such as cereals, wine, spices and liquorice, whilst other commodities such as beer and meat products that are susceptible of OTA contamination and are largely consumed are not included. In 2013, within the framework of the Regulation (EC) 882/2004 on official controls, the European Commission issued the mandate M/520 regarding the standardisation for methods of analysis for mycotoxins in food to the European Committee for Standardisation. Of the 11 priorities of the mandate, the one on "HPLC determination of OTA in meat, meat products and edible offal" was assigned to the Italian National Reference Laboratory for feed and food. The method was single-laboratory validated, and all the performance characteristics of the method were compliant with the corresponding reference values indicated in Regulation (EC) n. 401/2006. The method was applied to characterise a set of 5 pork-based materials (ham, kidney, liver and canned chopped pork) to be used for an inter-laboratory method validation study. Three ham materials (levels of contamination of 0.77, 2.22 and 12.3 μg/kg, respectively), one liver material (contamination level of 2.80 μg/kg) and one chopped pork meat (contamination level of 0.66 μg/kg) were tested for homogeneity and stability.

Occurrence and Safety Evaluation of Ochratoxin A in Cereal-based Baby Foods Collected from Iranian Retail Market

Contamination of agricultural commodities with ochratoxin A (OTA) is a worldwide concern in recent decades. Consumption of OTA-contaminated baby foods exerts health implications especially in children as the most vulnerable subpopulations. In the current study, for the first time in Iran, 64 baby foods (rice, wheat, and multigrain) samples from five different brands available in the Iranian market were analyzed to determine OTA level, using a HPLC with fluorescence detector. Overall, OTA was observed in 41% of analyzed samples with a mean and maximum level of 0.42 ± 0.27 and 1.1 μg/kg, respectively. OTA levels in five of 64 samples (7.8 %) were higher than the permissible limit recommended by European Commission (permissible limit: 0.5 μg/kg) and OTA levels in two of 64 samples (3.1%) were higher than the standard set by Iranian standard organization (1 μg/kg). The highest OTA contamination was observed in rice-based baby food cereals (1.1 μg/kg; 57% of the samples), followed by wheat-based (23%) and multigrain (20%) samples. OTA intake in infants (≥9 months old) was more than established provisional tolerable weekly intake by the Joint FAO/WHO Expert Committee on Food Additives (JECFA) and the European Food Safety Authority (EFSA) (100 and 120 ng OTA per kg of body weight, respectively). OTA content in baby food and cereals, as well as other raw foodstuff should be investigated comprehensively to reduce the exposure rate of young children to OTA.

Developments in mycotoxin analysis: an update for 2013-2014

This review highlights developments in the determination of mycotoxins over a period between mid-2013 and mid-2014. It continues in the format of the previous articles of this series, emphasising on analytical methods to determine aflatoxins, Alternaria toxins, ergot alkaloids, fumonisins, ochratoxins, patulin, trichothecenes and zearalenone. The importance of proper sampling and sample preparation is briefly addressed in a dedicated section, while another chapter summarises new methods used to analyse botanicals and spices. As LC-MS/MS instruments are becoming more and more widespread in the determination of multiple classes of mycotoxins, another section is focusing on such newly developed multi-mycotoxin methods. While the wealth of published methods during the 12 month time span makes it impossible to cover every single one, this exhaustive review nevertheless aims to address and briefly discuss the most important developments and trends.