Tightly closed dark green with thin stalks are the best to choose. Broccoli with any yellowing or tiny flowers on the head should be avoided.
Potatoes that are firm and no sprouts on them are best. Potatoes with green patches soft areas and wrinkles and sprouts should be avoided.
Tomatoes that are shinny and have a uniform skin texture are the best ones. Avoid tomatoes with bruises and cracks with pale spots on the skin.
Dry and firm onions are the best. Avoid onions that have soft and brown spots or look moist. Also onions having sprouts coming out should be avoided as they will deteriorate sooner.