JAKARTA, Indonesia (AP) -- Indonesia detected traces of radioactive cesium 137 at a clove plantation as it searches for the source of radioactive contamination that forced recalls of shrimp and spices exported to the U.S., a task force investigating the issue said Wednesday.

U.S. Food and Drug Administration officials blocked the import of all spices processed by PT Natural Java Spice of Indonesia in September after federal inspectors detected cesium 137 in a shipment of cloves sent to California.

That was the second food product from Indonesia to be recalled from sale due to radioactive contamination this year, following a recall of shrimp from another Indonesian company in August.

The task force found cesium 137 at a clove plantation in Lampung province. It also inspected clove processing facilities in Surabaya city in East Java province and another plantation in Central Java province, working with Indonesia's Nuclear Energy Regulatory Agency.

"We can confirm that contamination has been found on plantations in Lampung. The contamination was found in limited quantities and has not spread to other areas or commodities," said Bara Hasibuan, the task force's spokesperson in a written statement.

The nuclear regulatory agency recommended a temporary halt to sales of contaminated clove products pending further laboratory testing, while investigators continue to track the source of the contamination.

"The government is moving quickly to localize this contamination so that it does not spread to other areas. The public and businesses are advised to remain calm and wait for the official laboratory test results," Hasibuan said.

The task force traced the earlier contamination of shrimp to a steel factory in the Cikande industrial estate, around 3 kilometers (2 miles) from the PT Bahari Makmuri Sejati shrimp processing facility, which sends millions of pounds of shrimp to the U.S. each year.

Experts in nuclear radiation agree that health risks are low since only very low level of radioactivity were identified, but they say it's important to determine the contamination's source and share that information with the public.