Isolation and identification of ochratoxin A-producing Aspergillus section Nigri strains from California raisins

Abstract

Aims: To determine incidence and levels of ochratoxin A (OTA) in California raisins and to isolate and characterize OTA‐producing fungi from California raisin vineyard populations. Methods and Results: Forty raisin clusters sampled from four California vineyards in the San Joaquin Valley were analysed for OTA content using immunoaffinity and HPLC methods. OTA was detected in 93% of the samples, at levels from 0·06 to 11·4 ng g−1. From these raisin samples, a total of 400 strains of Aspergillus were isolated and analysed for OTA production. Twelve isolates (3%), from five raisin samples, produced OTA. These isolates were identified as Aspergillus carbonarius, based on morphological characteristics and multilocus sequence analysis. Levels of OTA produced by these isolates on raisin agar ranged from 0·9 to 15 μg g−1. Conclusions: OTA is a common contaminant of raisin vineyards, but average levels are much lower than EU regulatory limits for dried fruit. The primary species responsible for OTA contamination in California raisins is A. carbonarius. Significance and Impact of the Study: This study illustrates that low‐level OTA contamination of raisins occurs in California and that ecological studies of A. carbonarius within the Aspergillus section Nigri population on raisins are warranted to monitor ochratoxigenic potential of the crop.

Ochratoxin A in dried grapes in Hamadan province, Iran

“…Ochratoxin A (OTA) is of public health concern because it is nephrotoxic, carcinogenic, immunesuppressive, teratogenic, hepatotoxic and cytotoxic (Palumbo et al 2011). Since OTA could cause cancer in humans, it was classified in group 2B by the International Agency for Research on Cancer (IARC 1993).…”

“…Penicillium (P. verrucisum and P. viridicatum) genera (Iha et al 2009;Palumbo et al 2011;Kuang et al 2012). Ochratoxin A (OTA) is of public health concern because it is nephrotoxic, carcinogenic, immunesuppressive, teratogenic, hepatotoxic and cytotoxic (Palumbo et al 2011).…”

A validated dispersive liquid-liquid microextraction method for extraction of ochratoxin A from raisin samples

“…Ten percent of 264 sultana sample in Turkey were contaminated over than EU regulatory limits (Meyvaci et al 2005). Palumbo et al reported that OTA is a common contaminant of raisin, but average levels for dried fruit are much lower than EU recommends legal limits (Palumbo et al 2011).…”

Comparison of five different C18 HPLC analytical columns for the analysis of ochratoxin A in different matrices

“…Dried vine fruits (raisins, sultanas and currants) contribute to the total dietary exposure to OTA [7,8]. Thus, the European Union has established regulatory levels in order to control the presence of OTA in cereals, grape and coffee-derived products, raisins and other dried vine fruits [9,10].…”