A sword???
They brought back knowledge that had been lost before the crusades
water can not preserve food it attracts mold
Diabeetus and ADHD.
Because they were so good
Freezers have a motor. This motor is used to bring cold air to low temperatures. Then it can freeze food or whatever when placed in it. A freezer is great because it can save your food and will preserve it.
On meat, salt can preserve food.
They brought trade.
cinnamon!
well once you have cooked the food it is ready to it so there is no need to preserve it
They stuffed the food with salt which would let it dry out and that's how they would preserve it.
Water doesn't necessarily preserve food. However, the canning process can preserve food. The boiling process can prevent any transfer of bacteria, fungus or microbes.