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Objective: To assess the nutrient profile of yoghurts and dairy desserts. Design: Nutrition information panels and product labels on yoghurts and dairy desserts offered for sale were surveyed in 2005 and 2008 and nutrients analysed by two nutrient profiling systems. Setting: A large supermarket in metropolitan Melbourne, Australia. Results: In total, 248 and 140 dairy snacks (yoghurt, fromage frais or dairy desserts) were surveyed in 2005 and 2008, respectively. Over this time, median packet size rose significantly (P # 0?001). In yoghurts, median energy and total fat content also increased while protein decreased (all P , 0?05). The proportion of 'full-fat' products rose from 36 % to 46 %. Because of the addition of sugar, most 'reduced-fat' yoghurts had energy content similar to many 'full-fat' yoghurts. Overall, the proportion of yoghurts and dairy desserts that were 'less healthy' (i.e. displaying one or more 'red traffic lights' for high fat, saturated fat, salt and sugar content) rose from 12 % in 2005 to 23 % in 2008. Only 1-2 % could be deemed 'healthy' by the most stringent criterion (displaying four 'green traffic lights'), while 21 % (2005) or 28 % (2008) were 'healthy' by a nutrient profiling system that included a score for protein. Sucrose, the most common sweetener, was found in levels up to 29 g/100 g. Claims on packaging mainly related to Ca, fat or protein content. Few labels referred to sugar content. Conclusions: The deterioration in nutrient quality of yoghurts needs to be redressed.

As current techniques for the quantification of bacteria are laborious and often imprecise, instrumental approaches such as sedimentation field-flow fractionation (SdFFF) are attractive. In this technique, fluorogenic dyes specific for nucleic acids are used to identify bacterial cells. Bacterial biomass can be quantified directly with SdFFF if the specific fluorescence of bacterial cells is constant. The effect of different growth conditions on the specific fluorescence of one strain each of Escherichia coli, Pseudomonas aeruginosa, Proteus mirabilis and Staphylococcus epidermidis stained with 4',6-diamidino-2-phenylindole was examined. Specific fluorescence varied over a 500-fold range, from 0.22 to 103 arbitrary fluorescence units per cell. Specific fluorescence was highest when cells were in log phase, and lowest when cells were in stationary phase. Specific fluorescence decreased when cells harvested in log phase were starved for 7 d in a carbon-free minimal medium, and increased rapidly (within 2 h) after cells were relieved from carbon limitation. Such variations in specific fluorescence must be considered when using gross fluorescence as a direct indicator of bacterial numbers in the SdFFF technique for quantifying bacterial biomass. Moreover, they have serious implications for the application of fluorescence techniques in other instrumental approaches for bacterial enumeration in environmental samples.