Analytical quality assurance for the WHO GEMS/Food‐EURO programme—results of 1993/94 laboratory proficiency testing

Abstract

As a means of assessing the performance of European laboratories who contribute analytical data on food contamination to the World Health Organization (WHO) Global Environmental Monitoring Scheme (GEMS), a series of five proficiency testing exercises were carried out during 1993 and 1994. In total 136 laboratories from 21 different countries took part in one or more of the exercises which covered the analysis of trace elements (lead, cadmium and mercury) in milk powder, pesticides (organochlorine, organophosphorus and pyrethroid) in spinach powder, nitrate in spinach powder, aflatoxins in nut-based animal feed and patulin in apple juices. The proficiency testing was carried out according to the ISO/IUPAC/AOAC INTERNATIONAL Harmonized Protocol and laboratories were awarded z-scores signifying their analytical capability based on their reported results for each of the respective exercises. Overall 60% of laboratories were satisfactory for accuracy for trace element analysis, 41% for pesticides, 43% for nitrate, 88% for aflatoxins and 53% for patulin. These results gave an overall poorer performance (68%) than the average for other similar schemes (79%), indicating the need for care in collating data for such programmes as GEMS and the need for remedial measures to assist in improving performance.

Yield and biosynthesis of nitrogenous compounds in fruits of green bean (Phaseolus vulgaris L cv Strike) in response to increasing N fertilisation

“…4 However, the excessive use of nitrogenous fertiliser in the form of NO 3 − can increase the concentration of this anion in foods of vegetal origin. 5 An excess of N in general harms the quality of fruits and their commercial yield, 3,6,7 in addition to polluting aquifers as well as surface water by leaching. 8 Few works have studied N metabolism in fruits, 9 but one of the enzymes that participates in N assimilation is known to be glutamine synthetase (GS), which catalyses glutamine synthesis from glutamate, ATP and NH 4 + .…”

Commercial Yield and Quality of Fruits of Cucumber Plants Cultivated under Greenhouse Conditions: Response to Increases in Nitrogen Fertilization

“…Nitrate is studied by the World Health Organization (WHO) as one of the compounds detrimental to human health when present in food at high concentrations (3.5-4.5 mg g -1 fw) (Van der Boon et al, 1990;Weigert et al, 1997). In our experiment, the highest NO 3 -concentrations were found at the N5 application rate (Table 1).…”

The Analytical Quality Assurance of Food Composition Data—Experience of Cyprus, a Small Country

“…The selected methods were based on o$cial ones, i.e., Association of O$cial Analytical Chemists International (AOACI), American Oil Chemists Society (AOCS), European Committee for Standardisation (CEN), Nordic Committee on Food Analysis (NMKL), which have been validated by collaborative trials or, were in-house validated methods, which in some cases, were novel work (with subsequent publication in scienti"c journals), and (ii) the participation in appropriate pro"ciency testing schemes or other external quality-control checks in the food sector such as: Food Analysis Performance Assessment Scheme (FAPAS), Norwich, U.K. GEMS/Food-EURO (Weigert et al, 1997), WHO/IARC (A#atoxin Check Sample Survey Programs, IARC Lyon, France), AOCS Smalley Check (AOCS Smalley Check Sample Program), LIV-SMEDELSVERKET (National Food Administration, Upsala, Sweden) and EQA/PHLS (External Quality Assessment schemes organized by the Public Health Laboratory Service, U.K.) for microbiological analyses (food and water).…”