Orange juice futures soared limit up for a second day after a warning by food watchdogs of findings of an illegal pesticide in imports added to supply concerns fostered by cold weather in Florida.

Orange juice for March delivery soared 20 cents a pound in New York to end at 207.75 cents a pound, a record high for a nearest-but-one contract. The jump took the contract's gain in two days to nearly 17%.

The expiring, and little-traded, January contract ended at a record close for a spot lot of 212.75 cents a pound.

The rally followed a warning from the US Food and Dry Administration that it was conducting tests on orange juice, after a company cautioned that it had found "low levels" of the fungicide carbendazim in its own products, and some of an unnamed competitor.

'Unlawful pesticide'

Carbendazim, while cleared for use on citrus crops in many countries, has not been approved by the US, where it counts as an "unlawful pesticide chemical residue", the FDA said.

The contamination is believed to stem from imports from Brazil, the world's top producer of oranges and orange juice.

"Industry reports indicate that carbendazim is present in orange juice products from the 2011 crop from Brazil, where the fungicide is used legally under Brazilian law to combat black spot," a fungus that grows on orange trees.

The levels of the chemical so far identified are too low to warrant the withdrawal of juice, the FDA said.

However, it warned that it was conducting its own tests which could force recalls or, if found on imports, their denial of entry into the US.

"If the agency identifies orange juice with carbendazim at levels that present a public health risk, it will alert the public and take the necessary action to ensure that the product is removed from the market."

Cold concerns

The risk of a squeeze on imports from Brazil compounded supply fears provoked by cold weather in Florida, America's top citrus state, where cold weather which caused some damage to groves last week was forecast to return.

The March orange juice contract closed up 10 cents on Monday, the maximum allowed on the day, prompting the expansion in trading limits today.

Oranges are seen at risk if temperatures drop below 2 degrees Celsius, about 28 degrees Fahrenheit, for more than four hours.

America imported more than $260m of fruit juice from Brazil in the first 10 months of 2011, according to the US Department of Agriculture.