Accuracy of formula preparation equipment for liquid measurement

Abstract

BackgroundModular specialist feeds may consist of a number of individual liquid ingredients. Accurate feed preparation is dependent on competent liquid measurement. We investigate the accuracy of two measuring jugs (one retail mix-and-measure; and one produced to laboratory standards); and the influence of volume and technique on accuracy.Materials and methods20 health professionals aged 18–60 y (mean: 46 y) measured 3 different volumes of water with each of two measuring jugs. For each volume with each jug, 2 measurements in randomised order were made: 1) eye-level with the jug, and 2) standing upright (total of 12 measurements). Measured quantities were weighed and the difference between measured and target volumes calculated.ResultsThe laboratory jug was more accurate (mean difference 9.3 ml, range − 30.5 to 57.5 ml, std error mean 1.59) than the retail jug (mean difference − 17.7 ml, range − 92.0 to 48.5 ml, std error mean 1.59). Accuracy improved with increased volume (450 ml: mean difference − 9.4 ml, range − 75.5 to 49.5 ml, std error mean 1.95; and 810 ml: mean difference − 0.7 ml; range − 92.0 to 43.0 ml, std error mean 1.95).ConclusionsAccurate measurement of liquid ingredients is difficult to achieve even for trained professionals. The cumulative effect of many different liquid measurement errors (inappropriate jug type, inaccurate volume measured and poor technique) may lead to clinically important errors in the preparation of modular specialist feeds.

Variability and Error in Measurement of Infant Formula Powder and Water: An Experimental Study

“…The present study advances the current body of evidence, showing a substantial difference in error from formula powder measurement versus error from water measurement, and how the divergent directions of those errors combined to exacerbate under-dilution. Ostensibly, water measurement poses a less complex measurement problem, although extant literature has identified how even health professionals can have difficulty with liquid measurement accuracy [17]. Furthermore, baby bottle manufacturers may contribute to measurement difficulties with difficultto-read markings, irregularly shaped bottles, or inaccurate markings on the bottle contributing to barriers to preparing appropriate concentrations of infant formula [14].…”