Talk to Pediatrician on Colour Of Poop

Salam.. my 4 month baby who was on enfamil since birth was switched to morinaga 2 weeks back after which she used to pass stool during every feed..upon consultation she was again switched to similac neosure.. now its been only one day and i have offered her 5 feeds uptil now and she has pooped 3 times (2 during the feed and one randomly) but now the colour of poop is changed into something like greenish black with some seedy particles..though the texture of poop is same as befor but the colour is changed..whats the reason..should i leave all the brands and go back to enfamil again? Thanks in advance..