To be practical don't bring anything opened. All canned goods normally are OK but nothing otherwise is consistently accepted. I have found that the inspectors do not really know their own rules so rather than confuse them I bring anything in a tin or a sealed jar, nothing otherwise. That seems to work. Even infant food that is opened will often be confiscated. Remember than anything that is more than 100ml must be in checked baggage. They do not accept exceptions with any consistency even is the rules provide for, say, baby formula.