Replace Text but not from within a word

I am new in R.

I have a file. This file contains name of the companies.
'data.frame': 494 obs. of  1 variable:
 $ V1: Factor w/ 470 levels "3-d engineering corp",..: 293 134 339 359 143
399 122 447 398 384 ...

Problem: I would like to remove "CO" (As it is the most frequent word). I
would like "CO" to removed from BOEING CO --> BOEING but not from SAGINAW
*CO*UNTY INC*. *

text = c("BOEING CO","ENGMANTAYLOR CO","SAGINAW COUNTY INC")

gsub(x = text, pattern = "CO", replacement = "")

[1] "BOEING "       "ENGMANTAYLOR " "SAGINAW UNTY"

Thanks in advance.

- Sam