Terry Koerner

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. Examples include acrylamide as a food-processing-induced contaminant, bisphenol A as a food packaging-derived chemical, melamine and related compounds as food adulterants and persistent organic pollutants, and perchlorate as an environmental contaminant. Ochratoxin A, fumonisins, and paralytic shellfish poisoning toxins are examples of naturally occurring toxins whereas sulfites, peanuts, and milk exemplify common allergenic food additives/ingredients. To deal with the increasing number of sample matrices and analytes of interest, two analytical approaches have become increasingly prevalent. The first has been the development of rapid screening methods for a variety of analytes based on immunochemical techniques, utilizing ELISA or surface plasmon resonance technology. The second is the development of highly sophisticated multi-analyte methods based on liquid chromatography coupled with multiple-stage mass spectrometry for identification and simultaneous quantification of a wide range of contaminants, often with much less requirement for tedious cleanup procedures. Whereas rapid screening methods enable testing of large numbers of samples, the multi analyte mass spectrometric methods enable full quantification with confirmation of the analytes of interest. Both approaches are useful when gathering surveillance data to determine occurrence and background levels of both recognized and newly identified contaminants in foods in order to estimate human daily intake for health risk assessment.

N-demethylation of cyamemazine via non-classical Polonovski reaction and its conjugation to bovine serum albumin.

A modified Polonovski reaction has been employed to obtain the N-demethylated metabolite of the neuroleptic drug cyamemazine. The synthesis involves N-oxide formation, isolation of the corresponding N-oxide, and a FeSO(4)·7H(2)O mediated Polonovski reaction to afford the desired monodesmethyl cyamemazine. In a subsequent step the hapten N-demethylcyamemazine-hemiglutarate was synthesized and its conjugated to bovine serum albumin (BSA).

Serum Proteomic Analysis for the Identification of Biomarkers by Two-Dimensional Differential Gel Electrophoresis (2D-DIGE) after Exposure to theFood-Processed Contaminant Furan

Background: Furan is a compound known to be present in cooked or thermally-processed foods by formation through traditional heat treatment processes and also known to be a potent hepatotoxin. To identify potential biomarkers of furan exposure, two-dimensional differential gel electrophoresis (2D-DIGE) was performed on individual serum samples to identify proteomic profiles that were differentially expressed in rats exposed to furan at 0, 0.03, 0.5 and 8.0 mg/kg bw/day. Results: There were no differences in protein expression between control and the 0.03 and 0.5 mg/kg bw/day dose groups (one-way ANOVA P<0.05, avg ratio +1.5). At the 8.0 mg/kg bw/day of furan exposure, there were 22 protein spots that showed a difference in expression when compared to the control animals (one-way ANOVA P<0.05, avg ratio +1.5). After manual spot picking, four proteins were identified by standard in-gel tryptic digestion followed by mass spectrometry and bioinformatics. Conclusions: Of these four proteins apolipoprotein C-III (isoform CRA_b) and fetuin-B (precursor) were upregulated, whereas α-1-macroglobulin and pre-proapolipoprotein A-1 were down-regulated. These biomarkers could be of diagnostic relevance to identify furan exposure.

Foreword to the Special Issue on Food Allergen Methodologies

Food Allergy is an on-going public health problem and continues to be a challenge to both the clinical community and the food industry. Food safety regulators, industry, and consumer groups are working towards the development of the appropriate risk assessment and risk management procedures to prevent the inadvertent consumption of allergenic ingredients by allergic individuals, while not unduly impairing their choice. The availability of analytical methods to detect and determine levels of markers of priority allergens in foods are of the utmost importance to support standard setting initiatives, the development of compliance and enforcement activities, as well as to provide guidance to industry on implementation of quality control practices and ensuring the effectiveness of allergen-related sanitation techniques. Beginning in October of 2003, Health Canadas Food Directorate has hosted a series of workshops on Food Allergen Methodologies. These workshops aim to gather scientists, chemists, analysts, and other representatives from government agencies, academia, industry, and consumer associations, to discuss issues related to the detection, identification, characterization, and control of allergens in foods. Truly international in scope, these workshops have attracted participation from around the world, including European nations, Australia, Hong Kong, Japan, USA, as well as from all across Canada. This special issue of food analytical methods is dedicated to reporting on the fifth workshop on food allergen methodologies, which took place in Halifax, Nova Scotia, Canada, from May 11–14, 2008. Health Canadas Food Directorate, along with the Food Allergy Research and Resource Program of the University of Nebraska, USA, coorganized the event with support from MoniQA (Monitoring and Quality Assurance in the food supply—an international Network of Excellence cofunded by the European Union). The workshop was an opportunity to enhance consultation, information exchange, and to foster harmonization of method validation in the area of food allergens. The event gathered scientists, analysts, and other representatives from government agencies, university, and Food Industry. This special issue presents some highlights of the workshop which discussed method development for specific food allergens, method validation requirements, international initiatives such as that supported by the MoniQA network of excellence, as well as surveys aiming to determine levels of allergens in correspondence with labeling. The guest editors of this special issue would like to thank workshop participants and authors for making this workshop a success and for their contribution to this special issue. S. B. Godefroy Health Canada, Food Directorate, Sir Frederick Banting Research Centre, Ottawa, Canada e-mail: Samuel_Godefroy@hc-sc.gc.ca