You raise several questions, I’ll address each of them individually.
Someone claims that 61 countries require GMO labeling. There is a quasi-generalised requirement to label products of GM origin that are not considered to be substantially equivalent to their conventional counterpart, with a view that the consumer be informed on novel traits and food properties to facilitate informed choices. Labelling can be mandatory (Australia, EU, Japan, Brazil, China) or voluntary (Canada, Hong-Kong, USA). For products that are considered to be substantially equivalent, because they possess only input traits (such as insect resistant), there exists a large heterogeneity of approaches. Labelling can be product (Australia, New-Zealand, Japan, USA) or process-based (EU, Brazil, China).
What does a GMO label look like? A concrete example of GM label on food products sold in supermarkets in the EU is Reese’s chocolate and peanut bar, which states “produced from genetically modified sugar beets, corn and/or soybeans”. Click here to view an image of a GM label.
What is sufficient to require such a label? GM labelling is not like nutrition labelling. The objective is not to warn consumers on healthy – or less healthy – choices but as an application of the ‘freedom of choice’ principle as GM, conventional and organic products target different market segments. Only a handful of GM products are currently made available in supermarkets in the EU. This is the result of commercial decisions made by retailers in Europe, which tend to select products that are below the 0.9% GM ingredient threshold that exempts GM labelling. Recently, retailers in the UK have publically announced the end of their GM free policy for animal feed as this is not justified by health concerns and lead to higher prices for the food chain and ultimately for the consumer.
More information is available here: http://tescofoodnews.com/news/an-update-on-our-poultry-feed/.