Sending samples is difficult enough even if it is a non food item, courier services have to abide by very strict conditions with regards to invoices, declarations, otherwise they simply return the packages.
For food products, the Russian market imports millions of tonnes of food per day but they have a very strict regime for avoiding bringing in potentially contaminated food, even though they have rabies, they don't have BSE.
If the company needs to be sent food stuff and there is a business there, they can contact UKTI North West. We can look at the type of commodity coding and see what type of certification will be needed. Once this GOST is sorted out, companies need to be registered on the Rostechnadzor Hygiene list that can be found on the Russian website that authorises the company in question. This could be related to importing salmon, meat produce, fruit, pet food etc ....
There is a process to follow and can take a while - maybe up to 12 months.
If a company is engaged with a distributor then the best idea might be to arrange for the Russian client to visit the UK and they can take some samples back with them in their suitcase.
There are different rules with regard to vacuum packed food and this raises the question of the nature of food stuffs intended to be sent.
Hope this helps. If you would like to pursue this I can arrange for an International Trade Advisor to contact you.