Search for keys from an array within values of another array and replace

There are multiple ways to do this I'm sure. I have an array that looks like this:

$map=array(
'ABC'=>'first_three',
'DEF'=>'second_three',
'GHI'=>'third_three'
)

$info=array(
    array('x','XXABCXXXX','x','x','x'),
    array('x','XXXDEFXXXX','x','x','x'),
    array('x','XXXXXXXXXX','x','x','x'),
    array('x','XXXXXXXABC','x','x','x'),
    array('x','XXXXXXXXXX','x','x','x')
)

I want to do a find/replace so that the 2nd string in the array will be compared to the keys in $map and if any are found, they'll replace the key with whatever was in the $map.

array('x','XXfirst_threeXXXX','x','x','x')

I want to loop through $info so:

foreach ($info as $i){
    [something with $i[1] and $map]
}

What's the most efficient way to do this? Does it use "in_array"?