INTRODUCTION


Recent concerns regarding chemical contamination and bacterial and viral pathogens in seafood have prompted interest
in obtaining more accurate estimates of seafood consumption for Florida residents. As a result of these concerns, the
Florida Agricultural Market Research Center conducted a year-long study to determine per capital seafood consumption
by Floridians in 1993-1994.

A state-wide telephone survey of 8,000 households was a major part of this study. The surveyed households were
stratified by county, with each county represented in proportion to its population as reported by the 1990 Census (Bureau
of Economic and Business Research, 1993). Both at-home and away-from home seafood consumption, for a 7-day
period, was collected from a randomly selected adult within each household. Additional information on at-home
seafood consumption for each member of the household was collected from the primary food preparer of that household.


 Rationale for a Telephone Survey

Traditionally, food intake studies for epidemiological, nutritional and toxicological purposes have been based upon
weighed food records, i.e. actual observation of intake, or on diet histories recorded during lengthy personal interviews
conducted by professional dietitians. Other traditional food intake research methods have utilized the food record
(diary), usually self-administered by respondents for one, three or seven days. These methods, while reasonably
accurate, are tedious, time consuming and expensive. Because of these limitations, sample sizes for these methods are
generally quite small.

Due to the ambitious nature of this study, a novel methodology was utilized in order to meet the study objectives within
the prescribed time and budgetary constraints. The survey protocol incorporated the advantages of large scale
probability sampling with the efficiency of a telephone survey. Many of the features of traditional food intake research
were utilized, but the study was designed to reduce sources of bias that affect small scale, short-term studies.

A telephone survey approach was chosen because of its relatively low cost and the ease of probability sampling. In
support of a telephone survey, Peters' and Houseknecht's methodological review cites an USEPA report which indicates
the telephone survey approach is "rapidly becoming the principal method of collecting survey data in research situations
where probing or in-depth exploration of issues is not required." They also suggest that "telephone surveys may
minimize recall bias and achieve a better overall response than mail surveys because the personal contact involved may
encourage the respondent's participation and jog his [or her] memory" (Peters and Houseknecht, 1992). Further, in a
comparison of a weighed record food intake study and telephone recall by elderly subjects, Dubois and Boivin (1990)
conclude that "telephone contact is an acceptable way to obtain short term (24 hour) dietary recall from elderly
subjects". Thus, one could conclude that recall by younger subjects would probably be even better.


 Rationale for a 7-day Recall Period

Although many food intake studies have used 24 hour or three-day recall periods, there is substantial agreement that
short recall periods are less representative of individuals' usual consumption because of high day-to-day variability in
intake, particularly in affluent countries such as the U.S. where diets are extremely varied (Block, 1982; Medlin and
Skinner, 1988). Further, short-term recall periods may yield biased results if consumption data are not obtained for both
weekend and weekday periods (Medlin and Skinner, 1988).

A seven-day period has also been widely used for both the food record and food recall approaches. Although it can be
argued that the food record approach is more accurate, it has been found that there is a high degree of agreement
between seven day food records and subjects' ability to recall their consumption of foods, particularly those either
commonly or rarely eaten (Block, 1982).