It was a little more than just "seizing food and other items".
From the Link:
--"Sheridan launched what would become known as the Burning, a 12-day period when Union forces brought war to the residents of the valley. Mills, barns, homes, crops, supplies and anything considered a possible aid to the Confederate effort was systematically torched by Union cavalry.
No amount of mothers’ crying and children shrieking would deter the soldiers, who quickly got used to the response and efficiently went about their business.
It was total war.
The destruction was part of Grant’s new war plan. By bringing the war to civilians, he believed, he could end the conflict more quickly because the Southern army could not sustain itself without a stable food supply. Grant’s order was to “eat out Virginia clear and clean.”
He later expanded on that, saying, “if the war is to continue another year, we want the Shenandoah Valley to remain a barren waste.”
In the valley, as winter was coming on, the destruction included food of any description as well as the means to make food. Wheat was burned in the fields and in the barns. Mills used to grind grain into flour were destroyed.
Thousands of farm animals were either slaughtered in their pens or taken for the army’s use. Horses were rounded up.
Furnaces that produced iron for military use were wrecked. Tanneries were burned.
Although Sheridan’s orders directed soldiers to leave houses alone, many were burned either on purpose or by accident when fire spread from farm buildings. If the occasional officer was persuaded to spare a house, the next one through might not be so kind."--
https://www.washingtonpost.com/life...7ec46c-349b-11e4-9e92-0899b306bbea_story.html