Understanding school food service characteristics associated with higher competitive food revenues can help focus efforts to improve school food environments.

Many school food services sell extra foods and beverages, popularly referred to as "competitive foods," in addition to USDA school meals. On the basis of national survey data, most competitive foods and beverages selected by students are of low nutritional value. Recent federal legislation will allow schools that participate in USDA school meal programs to sell competitive foods only if the food items they sell meet nutrition standards based on the Dietary Guidelines for Americans. Concerns have been raised about the potential effects of limiting competitive foods on local school food service finances. However, national data indicate that only in a subset of schools do food services receive large amounts of revenues from competitive foods. These food services are typically located in secondary schools in more affluent districts, serving higher proportions of students who do not receive free or reduced price meals. Compared to other food services, these food services couple higher competitive food revenues with lower school meal participation. Increasing school meal participation could increase meal revenues to offset any loss of competitive food revenues. Replacing less-healthful competitive items with healthier options could also help maintain school food service revenues while improving the school food environment. Nationally consistent nutrition standards for competitive foods may encourage development and marketing of healthful products.

Application of heated inlet extensions to the TSI 3306/3321 system: comparison with the Andersen cascade impactor and next generation impactor.

Pharmaceutical aerosol size distribution analysis based on multi-stage inertial impaction is well accepted, though laborious. The TSI 3306 Impactor Inlet/3321 time-of-flight (TOF) Aerodynamic Particle Size Analyzer (APS) has been evaluated for its ease of use and potential for time savings during product development. However, instrument inlet modifications may be necessary for increased correlation with equivalent measurements obtained by inertial impaction following pharmacopeial methods. A heated inlet extension tube was located between the USP/Ph.Eur. throat and the Single-Stage Impactor (SSI) to promote evaporation of residual ethanol from aerosol droplets, generated from two formulations containing ethanol as semi-volatile solubilizer (8 and 20% w/w) for the active pharmaceutical ingredient. As temperature and extension length increased, the SSI-measured fine particle fraction (aerosol < 4.7 microm aerodynamic diameter) also increased, for the aerosols used in this study. These values correlated quite closely with equivalent measures made by multi-stage cascade impactor equipped with the same throat. Particle size distribution profiles measured with the APS for either formulation did not significantly change utilizing the heated extensions, suggesting that ethanol evaporation was largely complete at any condition by the time the aerosol entered the measurement zone of the TOF analyzer. The addition of a heated inlet extension may be useful to facilitate evaporation of residual semi-volatile species, especially when an agreement of APS-derived particle size mass distribution data from the SSI with multi-stage cascade impactors is desired. However, complete evaporation of the semi-volatile species may not be necessary for SSI-generated mass distribution to match conventionally used cascade impactors.