A recent delegation to Brazil and Paraguay, that included myself and Alyn Smith MEP, examined the possible impact of a trade deal that could open the door to more significant imports of beef.
The union has written to Mr Smith, asking him to secure reassurances at a European level that, before any trade deal is agreed, animal health issues will be properly addressed in the negotiations.
NFUS president Nigel Miller said: "The reports generated by the delegation's visit have focused attention on the potential impact of a trade deal with South America.
"Higher levels of meat imports may yet be an outcome of those negotiations, but we would want reassurances that animal health risks will be minimised and that production standards will match those required here.
"In parts of South America, foot-and-mouth disease (FMD) is still a real danger and a risk which Europe cannot afford to ignore."
Mr Miller went on to list a number of concerns about traceability and production methods adding: "It is unclear from the press reports whether the Brazilian industry is addressing these issues or if adequate traceability is in place to allow residue monitoring, but we look forward to fuller reports from the delegation in due course."
Alyn Smith commented: "I'm delighted as ever to work with NFUS. Its concerns are my concerns, and are precisely why we organised the visit.
"I'll be releasing my report on the visit at an event with the Scottish Beef Cattle Association early next year.
"We are enmeshed in CAP Reform at the moment and, while that is my current focus, I am increasingly aware that from the new year we are likely to see MERCOSUR (the South American trading bloc) trade deal rise up the agenda.
"My concern is that, with MERCOSUR being increasingly unlikely to act cohesively, the European Commission will instead seek a series of bilateral deals with individual countries, Brazil probably being the front runner.
"It is indeed vital that animal health concerns are at the top of the agenda and I went to Brazil and Paraguay specifically to see for myself what we're dealing with."
United Auctions sold 5043 prime lambs at Stirling on Thursday to a top £99 per head and 211p per kg to average 155.6p (+5.5p on the week).
The Cumberland and Dumfriesshire Farmers Mart sold 5179 prime lambs in Longtown on Thursday to a top of £98.80 and 253.3p to average 158.1p.
There were also 5635 cast sheep forward with heavy ewes selling to £128.50 for Texels and averaging £66.06, while light ewes peaked at £70.50 for Woodlands and levelled at £30.87. Rams sold to £118.50 for Texels and averaged £68.83.