AMSTERDAM (AP) - The Dutch Foods and Wares Authority says it has "preventatively" blocked all shipments from a Dutch slaughterhouse after investigators found horse meat in four shipments labeled as beef products. The agency did not identify the slaughterhouse, other than saying it was in the eastern province of Gelderland. It also said it could not tell from the slaughterhouse's records where the products containing horse meat may have been shipped. The agency has blocked the movement of all 690 tons of meat in the slaughterhouse's freezers and refrigerators until Feb. 3, to give the slaughterhouse's management time to trace all meat shipments between Jan 1, 2012, and Jan. 23, 2014. If the company cannot produce satisfactory documentation about where the products went, the slaughterhouse's meat will be recalled, the agency said.