I'm hoping someone can help me understand the food labelling on dairy products.  I've recently found a yoghurt I like at Aldi.  The brand is "Dairy Dream Diet Deli Yoghurt with real raspberry topping" (there is also a passion fruit variety).  I am suspicious of course because of the fruit topping component (which I mainly scrape off) but the nutrition panel lists only 7.9g sugar per 100g.  I seem to recall reading somewhere that usually 5g per 100g is lactose (safe), which I've taken to mean that it is only 3g per 100g of the sugar I really need to worry about.  Is this correct?  How can I tell how much sugar is lactose and how much is sucrose when it is all lumped together under the one line item "sugar".

Please help!  Cheers, Susan