As stated in the Hakohol, in general, probiotics which are stated to be vegan, are suitable for use. However it is recommended to use probiotics in capsule or tablet form because milk derivatives can be used in the growth medium. We do stock Optibac probiotics in powder and liquid form, however please be aware that they are listed in the Hakohol as kosher, but contain cholov akum. https://thekoshervitamins.com/