How to kill/get rid of flies?

How to get rid of existing flies in the production plant without impacting products?

Any tools or ways suggested?

First, before you can address the existing, you need to know from whence they came otherwise you're chasing your tail. You've got a hole/gap somewhere or you've got ingredients exposed.  Flies need food 

Remove as much stuff from one area at a time and perform a deep sanitation on each department to remove the eggs. 

There are some chemicals approved that theoretically could be sprayed on the Friday, allowed 24hours, then a full sanitation. BUT there cannot be any product in the room.

Truly, you need to figure out how they are getting in first

First of all inspect the area for gaps and holes, find out where the flies are coming from, maybe area need aggressive cleaning or maintenance repairs. Place the fly lights with the glue traps (but it must be maintained regularly, glue boards must be inspected and replaced, also light bulb must be replaced too according to manufacturer instructions) , You can place fly bait station (non-toxic, with pheromones). But the best advice is to contact Your pest control provider, they will definitely will be able to help You.

Hello richard,

P-revention

E-xclusion

S-anitation

T-reatment

You can prevent flies by removing anything that attracts them. Left-over food, uncollected garbage, open trash bins. Exclusion means gaps on your facilities must be covered/i\eliminated. Sanitation must be done and verified to ensure no attractants and other harborage of pests are not present. Ensure that no outside sources, like piggery or poultry or any activities surrounding plant. If you done the 3 items, then you need to do the treatment. Hire a professional PC to assist you in exterminating flies/pest.

regards,

redfox