The "food" is believed to contain some of those
1	The	the	DET	DT	Definite=Def|PronType=Art	3	det	3:det	_
2	"	"	PUNCT	``	_	3	punct	3:punct	SpaceAfter=No
3	food	food	NOUN	NN	Number=Sing	6	nsubj:pass	6:nsubj:pass|8:nsubj:xsubj	SpaceAfter=No
4	"	"	PUNCT	''	_	3	punct	3:punct	_
5	is	be	AUX	VBZ	Mood=Ind|Number=Sing|Person=3|Tense=Pres|VerbForm=Fin	6	aux:pass	6:aux:pass	_
6	believed	believe	VERB	VBN	Tense=Past|VerbForm=Part|Voice=Pass	0	root	0:root	_
7	to	to	PART	TO	_	8	mark	8:mark	_
8	contain	contain	VERB	VB	VerbForm=Inf	6	xcomp	6:xcomp	_
9	some	some	DET	DT	_	8	obj	8:obj	_
10	of	of	ADP	IN	_	11	case	11:case	_
11	those	that	PRON	DT	Number=Plur|PronType=Dem	9	nmod	9:nmod:of	_
