( ( ( The ( main sources ) ) ( of infection ) ) ( ( are ( contaminated ( ( water or ) ( ( milk ( and ( food handlers ) ) ) ( who ( are carriers ) ) ) ) ) ) . ) )
(ROOT (S (NP (NP (DT The) (JJ main) (NNS sources)) (PP (IN of) (NP (NN infection)))) (VP (VBP are) (VP (VBN contaminated) (NP (NP (NN water)) (CC or) (NP (NP (NN milk) (CC and) (NN food) (NNS handlers)) (SBAR (WHNP (WP who)) (S (VP (VBP are) (NP (NNS carriers))))))))) (. .)))
The main sources of infection are contaminated water or milk and food handlers who are carriers.
(ROOT (S (NP (NNP Water)) (VP (VBZ is) (NP (NP (DT the) (JJ main) (NN component)) (PP (IN of) (NP (NN milk))))) (. .)))