(S (S (ADVP (RB Now)) (COMMA ,) (S (BASENP (NN health) (NNS officials)) (VP (VBP say) (SBAR (S (BASENP (DT the) (NN contamination)) (VP (VBD came) (PP (IN from) (BASENP (NN cattle) (NN manure))))))))) (PERIOD .))