I have used MYP (Mannitol Egg Yolk Polymyxin) and it has worked well,giving on B. cereus colonies. Could there be something wrong with the media?or may be the preparation or the Polymyxin? You may need to cross check with all that.

You can use mannitol egg yolk polymyxin. Its selective media for B.cereus  and produce from more companies e.g. Himedia 

As I go through the available scholarly articles, polymyxin pyruvate egg yolk mannitol bromothymol blue agar (PEMBA) seems to be the best medium for Bacillus cereus.

Mannitol egg yolk polymyxin agar (MYP) is usually recommended.

Polymyxin is the selective agent, and egg yolk and mannitol are differential

agents.

Mannitol Egg yolk Polymyxin Agar (MYP Agar) is recommended for B. cereus.

This article may be useful to the research ...

www.agriculturejournals.cz/publicFiles/54734.pdf

good job

There is Bacillus Cereus Selective Agar ... with putting Egg Yolk Emulsion supplement 

There is Bacillus Cereus Selective Agar

You can try a selective medium used for isolation of Staphylococcus, named Chapman, wich contains a high concentration of NaCl.

MP

You can also Inoculate duplicate Bacara agar plates with each dilution of sample by spreading 0.1 mL evenly onto surface of each plate with sterile glass spreading rod. Incubate plates 18-24 h at 30°C and observe for colonies surrounded by precipitate zone, which indicates that lecithinase is produced. B. cereus colonies are usually a pink-orange color on Bacara and may become more intense after additional incubation. Select plates that contain an estimated 15-150 pink-orange, lecithinase-producing colonies. 

Please check the FDA web page about B. creus

You can try the Chapman medium usually used for isolation of staphylococcus species and containing high concentration of NaCl.

Sincerely.MP

B. cereus selective agar with addition of egg yolk and supplements to avoid mold growth

MYP agar is the best agar. Spread 0.2 ml of your dilutions.

Enumeration of B. cereus on polymyxine pyrovate-egg yolk-mannitol bromothymol blue agar at 35oC

Did you try the Chapman medium ( mannitol, phenol red, high concentration of Nacl ) ? I have isolated Bacillus from milk.

Sincerely

Thank you everybody!