There are a few good resources providing information about what food can be brought back from Mexico with you.
Note that presence of absence or SEEDS is not a determining factor in entrance requirements on any fresh fruits into California. If a fruit is prohibited whole, it is also prohibited cut into pieces. All agricultural products must be declared and are subject to inspection for pests and diseases before allowing entry. Any item failing inspection will be prohibited from entering the USA.
This is only a portion of the items not allowed to enter from Mexico, some fruits or vegetables not listed may be prohibited from entry.