import re

string = """
apple 4
bananas 5
bananas 5 7
apple 3
apple 6
bananas 3
bananas 4 5
apple 3
bananas 9 
"""

rx = re.compile(r"""
		^apple.+[\n\r]
		(?:(bananas.*)[\n\r]?)+
		""", re.MULTILINE | re.VERBOSE)

bananas = [m.group(1) for m in rx.finditer(string)]
print(bananas)