De Henauw S, Brants HAM, Becker W, Kaic-Rak A, Ruprich J, Sekula W, Mensink GBM, König JS, The EFCOSUM Group (2002): Operationalization of food consumption surveys in Europe: recommendations from the European Food Consumption Survey Methods (EFCOSUM) Project
Eur. J. Clin. Nutr. 56 Suppl 2: S75-88.

BACKGROUND: The EFCOSUM (European Food Consumption Survey Methods) Project aims at harmonizing food consumption surveys in European countries within the perspective of an overall Public Health Monitoring Programme. Harmonization implies the need for a common framework of procedures and tools, that are applicable and feasible in all potentially interested countries. A major element in such a framework is the protocol for the operationalization of a food consumption survey, referring to all practical, logistical and material conditions that need to be fulfilled in order to guarantee a successful implementation of such a survey. OBJECTIVE: The objective of this paper was to review a number of aspects of operationalization of food consumption surveys in detail. On the basis of the currently available knowledge and experience in Europe, consensus recommendations have been elaborated for an operationalization protocol that would be feasible for all European countries. METHODS: The EFCOSUM recommendations with respect to operationalization of food consumption surveys in Europe are mainly based on three sources of information, which have been discussed at several ad hoc expert meetings: experience from previous collaborative epidemiological studies, literature searches and results of two questionnaires, distributed among representatives from 23 European countries-all experts affiliated with experienced organizations in the fields of nutrition research and related fields. RESULTS: Consensus recommendations have been set up for the following topics: sampling, recruitment, fieldwork, biomarkers, interviewer qualifications and training and quality control. These recommendations have to be considered the best achievable common denominator within Europe at this time. In a number of cases, recommendations are presented in a hierarchical way, with a gradation from first choice options towards acceptable alternatives. CONCLUSIONS: It can be concluded that a high degree of standardization of fieldwork can be achieved within Europe. A number of specific problems and constraints will have to be solved in connection with the conduction of a real survey. These problems include, amongst others, country-specific decisions on, for example, target population, detailed sampling and recruiting procedures, interview setting and support. However, on the whole, these problems can be overcome and the main recommendations presented in this paper are considered feasible for every country in Europe. Application of the EFCOSUM operationalization protocol in European countries will contribute significantly to the quality and comparability of food consumption data across Europe. It is anticipated that the policy supporting and orienting potential of this type of databases-both at the national and at the EU supranational level-will be increased accordingly.