It should be clear by mid-April if Scottish school meals have been contaminated by horsemeat, according to the Food Standards Agency in Scotland.
Rural affairs secretary Richard Lochhead said this week that he could not yet guarantee that horsemeat had not been used in food served to pupils. He expected to have answers within "the next few days".
However, the results of the FSA's UK-wide authenticity survey will not be available until mid-April, although action would be taken sooner if problems emerged. Public institutions, including schools, are within the scope of the programme.
The FSA in Scotland has also asked all councils to visit approved meat- processing establishments in their areas to conduct a full audit - 229 establishments are involved. It is likely that these inspections will be completed by the end of March, a spokeswoman said.
Both investigations were targeting any establishment providing meals to schools, prisons and hospitals, she stressed.
The growing scandal over the discovery of horsemeat in some supermarket meals, including lasagne and spaghetti bolognaise, initially appeared to implicate suppliers from the continent. But this week two British firms - a slaughterhouse in West Yorkshire and a meat firm near Aberystwyth - came under suspicion.
Currently, only three Scottish local authorities have achieved the Soil Association Scotland's Food for Life catering mark, awarded for using more locally produced, seasonal, healthy and organic food in their school meals - Highland, East Ayrshire and Stirling. A further four authorities, including Fife and North Ayrshire, have applications in the pipeline.
Cordia, which supplies school meals in Glasgow schools, has been assured that all its products are from a reliable source, said a Glasgow City Council spokeswoman.
Meanwhile, samples taken from school meal suppliers for Edinburgh City Council have shown no evidence of a link with the implicated meat companies.