US health regulators blocked 20 shipments of orange juice last Friday, 11 of them from top producer Brazil, because they contained traces of a prohibited fungicide. The key March frozen concentrated orange juice contract rose 0.05 cent to finish at $2.015 per lb, trading from $2.00 to $2.0665. Benchmark March hit an all-time peak at $2.2695 per lb in the last two weeks on speculation the United States may ban Brazilian juice imports. Country Hedging Inc senior analyst Sterling Smith said the market was still mulling how it will eventually be resolved. Investors were getting wary about the juice market and reduced their exposure. Open interest, an indicator of investor exposure, stood at 25,603 lots, the lowest since Dec. 27, data from ICE Futures US showed. Traders said that with each day that passes by without a definitive decision on juice imports, futures will remain volatile and probably stay near $2 a lb. Brazil is the world's top citrus producer and accounts for half of all US juice imports and 10 percent of all US supplies. Brazilian juice is used by leading US producers such as Pepsico's Tropicana and Coca Cola's Minute Maid in a blend with oranges from Florida. Volume Monday hit over 1,500 lots by late New York business, some 50 percent under the 30-day norm, Thomson Reuters preliminary data showed. On Friday, the exchange said 2,758 lots were traded.