A typical hold altitude for pressured aircraft is just over 8,000'. Newer aircraft like the 787 will lower that to about 6,000'. Sealed products like crisps will appear to inflate but yoghurt, even in sealed tubs, if upside down will be pushed out of the container by the residual air inside. Air pressure at 8,000' is approx. 11 psi. The air was captured at 14 psi, therefore the pressure on the yogurt was 3 psi. Solution? Don't carry yoghurt or buy a better container.