So, I bought a block of (Cathedral City) cheese! A rectangular bloc, with one of those resealable strips. Unusually the reseal strip was at the top of the block (short end of rectangle). Normally to avoid being poisoned I try a small piece to make sure it's safe, which I did, then I had a normal amount with no problems. This continued until I got to the last portion of the cheese, which was badly poisoned. The sore stomach poison that lasts for several hours, but can be countaracted with Ibuprofen, after about 10 agonising minutes waiting for them to take effect.. Sneaky bastards must have poisoned only the bottom portion of the cheese to catch me out. Oh well, once bitten.