No carbon limitation after lower crown loss in Pinus radiata.

Background And Aims: Biotic and abiotic stressors can cause different defoliation patterns within trees. Foliar pathogens of conifers commonly prefer older needles and infection with defoliation that progresses from the bottom crown to the top. The functional role of the lower crown of trees is a key question to address the impact of defoliation caused by foliar pathogens.

Phytophthora pluvialis Studies on Douglas-fir Require Swiss Needle Cast Suppression.

Phytophthora pluvialis is associated with early defoliation and shoot dieback in Douglas-fir in Oregon and New Zealand. In 2013, P. pluvialis was described from mixed tanoak-Douglas-fir forests in the Pacific Northwest and concurrently recognized as the main causal agent of red needle cast (RNC) in New Zealand radiata pine plantations.

Toxicology of 3-epi-deoxynivalenol, a deoxynivalenol-transformation product by Devosia mutans 17-2-E-8.

Microbial detoxification of deoxynivalenol (DON) represents a new approach to treating DON-contaminated grains. A bacterium Devosia mutans 17-2-E-8 was capable of completely transforming DON into a major product 3-epi-DON and a minor product 3-keto-DON. Evaluation of toxicities of these DON-transformation products is an important part of hazard characterization prior to commercialization of the biotransformation application.

An epimer of deoxynivalenol: purification and structure identification of 3-epi-deoxynivalenol.

In an investigation of deoxynivalenol (DON)-transformation products by Devosia mutans 17-2-E-8, the major product was identified as 3-epi-DON. This DON-transformation product was analysed by liquid chromatography and identified by congruent retention time and UV/Vis spectrum, as well as mass spectrometric data. Nuclear magnetic resonance (NMR) experiments including correlation spectroscopy (COSY), heteronuclear single quantum coherence (HSQC) and nuclear overhauser effect (NOE) were conducted for structural characterisation of 3-epi-DON.

Analysis of cocoa products for ochratoxin A and aflatoxins.

Eighty-five samples of cocoa products sampled in Canada were analysed for ochratoxin A (OTA) and aflatoxins in 2011-2012. Inclusion of the aflatoxins in this survey required additional method development. Chocolate was extracted with methanol-water plus NaCl, while for cocoa two successive extractions with methanol and methanol-water were made.

Alternaria toxins alternariol and alternariol monomethyl ether in grain foods in Canada.

Alternaria alternata has been reported to be the most common fungus on Canadian Western wheat. The Alternaria toxins alternariol (AOH) and alternariol monomethyl ether (AME) are mutagenic in vitro and there is also limited evidence for carcinogenic properties. They have been found in wheat from Europe, Argentina, China and Australia, but they have not been looked for in Canadian grains or grain foods.

Monitoring of shrimp and farmed fish sold in Canada for cyanobacterial toxins.

Sixty-one samples of shrimp and 32 samples of farmed fish collected from retail markets across Canada were analyzed for cyanobacterial toxins, including microcystins, paralytic shellfish poisons (saxitoxins), cylindrospermopsin, and β-N-methylamino-L-alanine, using established methods of analysis. None of these toxins were detected in any of the samples. Some shrimp samples screened for paralytic shellfish poisons showed the presence of unknown peaks in the chromatogram after periodate oxidation.

Challenges and trends in the determination of selected chemical contaminants and allergens in food.

This article covers challenges and trends in the determination of some major food chemical contaminants and allergens, which-among others-are being monitored by Health Canada's Food Directorate and for which background levels in food and human exposure are being analyzed and calculated. Eleven different contaminants/contaminant groups and allergens have been selected for detailed discussion in this paper. They occur in foods as a result of: use as a food additive or ingredient; processing-induced reactions; food packaging migration; deliberate adulteration; and/or presence as a chemical contaminant or natural toxin in the environment.

Liquid chromatographic determination of the cyanobacterial toxin beta-n-methylamino-L-alanine in algae food supplements, freshwater fish, and bottled water.

Beta-N-Methylamino-L-alanine (BMAA) is a neurotoxin originally found in cycad seeds and now known to be produced by many species of freshwater and marine cyanobacteria. We developed a method for its determination in blue-green algae (BGA) food supplements, freshwater fish, and bottled water by using a strong cation-exchange, solid-phase extraction column for cleanup after 0.3 M trichloroacetic acid extraction of BGA supplements and fish.

Incomplete recoveries of fumonisins present in naturally contaminated corn foods from an immunoaffinity column.

Following previous observations of apparent instability of fumonisin B1 in corn starch and corn meal, immunoaffinity column (IAC) cleanup, of the type used in the analysis of commercial starch-containing corn foods for fumonisins, was investigated. Foods analyzed for naturally occurring fumonisins B1, B2, and B3 included corn flour (3 different products), corn meal, and corn flakes. In 2 series of experiments, fractions were eluted by gravity or vacuum from narrow- or wide-bore Fumonitest IACs either with 2 x 2 mL methanol, followed by 2 mL methanol-water (8 + 2, v/v), or with 2 mL methanol, then 2 mL methanol-water (8 + 2, v/v).

Survey of dry pasta for ochratoxin A in Canada.

Ochratoxin A (OTA) was determined in 274 samples of dry pasta sold across Canada in 2004 to 2006. Ground sample was extracted with acetonitrile-water (6:4 [vol/vol]), filtered, diluted with phosphate-buffered saline, and cleaned with an immunoaffinity column. Analysis was by reversed-phase liquid chromatography with fluorescence detection, and in the second year by liquid chromatography-electrospray tandem mass spectrometry as well.

Occurrence of deoxynivalenol and its major conjugate, deoxynivalenol-3-glucoside, in beer and some brewing intermediates.

Since deoxynivalenol (DON), the main representative of Fusarium toxic secondary metabolites, is a relatively common natural contaminant in barley, its traces can be detected in many commercial beers. Our previous study reporting for the first time the occurrence of relatively high levels of DON-3-glucoside (DON-3-Glc) in malt and beer prepared from relatively "clean" barley (semiscale experimental conditions) induced a follow-up investigation focused on this DON conjugate in commercial beers. The current survey involving in total 176 beers, representing different brands, and collected at various markets, has documented a ubiquitous occurrence of DON-3-Glc in this product.

Biomarkers of human exposure to ochratoxin A.

Low blood serum/plasma concentrations of ochratoxin A (OTA) have been reported for healthy persons in more than 20 countries. Epidemiology studies in Bulgaria, Romania, Spain, the Czech Republic, Turkey, Italy, Egypt, Algeria and Tunisia have found significantly higher serum or plasma levels of OTA in patients with certain kidney disorders compared to healthy people, although the association may not be a causal one. Regional variations within one country, seasonal differences and variation within one person were found in some studies.

Improved extraction of ginkgotoxin (4'-O-methylpyridoxine) from Ginkgo biloba products.

A simple extraction procedure was applied to the analysis of canned/packaged white nuts and Ginkgo biloba extracts. Extraction by shaking with water at room temperature was more convenient to use than a previously published Soxhlet procedure for analysis of packaged Ginkgo biloba seeds (white nuts) for ginkgotoxin; recoveries from spiked dried seeds by the simple extraction procedure averaged 76%. Determination was by liquid chromatography with UV or fluorescence detection.

Liquid chromatographic determination of alpha-solasonine in frozen green peas as an indicator of the presence of nightshade berries.

Nightshade berries containing glycoalkaloids can be a contaminant in green peas. Methodology was developed to detect this contamination. The glycoalkaloid alpha-solasonine was extracted from frozen green peas with 1% (v/v) acetic acid, cleaned up on a C18 cartridge, and determined by liquid chromatography with UV detection at 200 nm.

Liquid chromatography-mass spectrometry and liquid chromatography-tandem mass spectrometry of the Alternaria mycotoxins alternariol and alternariol monomethyl ether in fruit juices and beverages.

Alternariol (AOH) and alternariol monomethyl ether (AME) are among the main mycotoxins formed in apples and other fruits infected by Alternaria alternata. For determination of AOH and AME by LC, apple juice and other fruit beverages were cleaned up on C18 and aminopropyl solid-phase extraction columns. Positive and negative ion mass spectra of AOH and AME under electrospray (ESI) and atmospheric pressure chemical ionization (APCI) conditions were obtained.

Extraction of fumonisins B1 and B2 from white rice flour and their stability in white rice flour, cornstarch, cornmeal, and glucose.

To extract fumonisin B1 (FB1) and fumonisin B2 (FB2) from Thai white rice flour, different solvent mixtures, temperatures, pH values, and addition of enzymes or ethylenediaminetetraacetic acid disodium salt (Na2EDTA) were examined. Three extractions with 0.1 M Na2EDTA achieved the highest recoveries.

Methods of analysis for ochratoxin A.

The mycotoxin ochratoxin A (OTA) is produced by the fungi Aspergillus alutaceus and Penicillium verrucosum and has carcinogenic, nephrotoxic, teratogenic and immunosuppressive properties. The levels of OTA in foodstuffs are regulated in several countries, so reliable and sensitive methods are necessary for its determination. Procedures for extraction of OTA from ground foods generally use an organic solvent in the presence of acid or an extraction solvent containing aqueous sodium bicarbonate.

Analysis of Beer for Fumonisins.

Forty-one samples of beer were analyzed for fumonisins B and B (FB and FB) using an immunoaffinity column cleanup followed by liquid chromatographic (LC) analysis. These samples included three later brand resamplings. All LC analyses were carried out using -phthaldialdehyde/2-mercaptoethanol (OPA/MCE) and/or 4-fluoro-7-nitrobenzofurazan (NBD-F) derivatization procedures.