Jakarta. Federal regulators have detected potential radioactive contamination in a second food product from Indonesia, even as recalls of potentially tainted shrimp continue to mount. The discovery raises questions about the source of the unusual problem.

US Food and Drug Administration officials last week blocked imports of all spices from Natural Java Spice after federal inspectors detected cesium-137 in a shipment of cloves sent to California.

The move follows an August import alert on Bahari Makmur Sejati (BMS Foods), which ships millions of pounds of shrimp annually to the US.

Cesium-137: What It Is
Cesium-137 is a radioactive isotope produced as a byproduct of nuclear reactions, including bombs, testing, reactor operations, and accidents. Trace amounts are widespread in the environment, including in soil, food, and air.

What Officials Found
US Customs and Border Protection detected cesium-137 in shipping containers of shrimp from BMS Foods at several ports. The FDA confirmed cesium-137 in one sample of breaded shrimp. The company has shipped roughly 84 million pounds (38 million kilograms) of shrimp to the U.S. this year, accounting for about 6 percent of US imported shrimp, according to Import Genius.

This month, FDA tests found cesium-137 in one sample of cloves from Natural Java Spice, which has shipped approximately 440,000 pounds (200,000 kilograms) of cloves to the US this year.

Health Risks
No contaminated food has been sold in the US, the FDA emphasized. Hundreds of thousands of packages of frozen shrimp sold at Kroger and other grocery stores have been recalled due to potential contamination.

While detected levels are below thresholds requiring emergency health measures, long-term exposure could increase certain cancer risks.

Possible Source
The cause of contamination remains unclear. The two processing facilities are roughly 500 miles (800 kilometers) apart. The International Atomic Energy Agency suggests radioactive scrap or melted metal near the shrimp plant could be the source. Indonesian regulators reported detecting cesium-137 at a site outside Jakarta. Contaminated medical equipment or shipping containers may also be contributing factors, said Steve Biegalski, a nuclear medicine expert at Georgia Tech.

Consumer Guidance
Consumers should avoid recalled shrimp potentially contaminated with cesium-137. Four firms have issued recalls since August:

• Aug. 21: Southwind Foods, LLC

• Aug. 22: Beaver Street Fisheries, LLC

• Aug. 27: AquaStar (USA) Corp – Kroger Brand

• Aug. 28: AquaStar (USA) Corp – AquaStar Brand

• Aug. 29: Southwind Foods, LLC – Expanded recall

• Sept. 19: AquaStar (USA) Corp – Expanded recall

• Sept. 23: Southwind Foods, LLC – Expanded recall

• Sept. 23: Lawrence Wholesale, LLC – Kroger Brand