I have been feeding raw for about 8 months now and all is going incredibly well. However, I buy packets of lambs hearts, kidneys and liver from Tesco which I then chop into portions and freeze as there is far too much to use before it expires. I just noticed this week (a bit slow on the uptake!) that there is some tiny print on the label that says it has been previously frozen (you might think that the fact it was from NZ might have alerted me to this earlier!). Now I am worried that I should not be refreezing it - I have been doing this unwittingly for some months without any apparent ill effects but would stop if I knew it could cause a problem. Why are we told not to do this? What is the danger? I can probably get liver and kidney fresh but my local butchers don't stock heart and I don't want to stop feeding this.

its  not dangerous providing that it is fully frozen again.... the reason they tell you this is because the animal cells become rigid when it is frozen as they are full of water. when defrosted the cell membranes relax but they have been broken, much like water pipes during a freeze. then you re freeze the meat and the cells leak all the frozen water out. it makes the meat go mushy and takes longer to fully defrost as ice crystals form on the inside. but providing it is fully thawed it should be fine