The world’s population is projected to hit 9 billion by midcentury, and we’ve been reporting on how we’re going to feed all those people in our series “Food for 9 Billion.” There are lots of ways you can produce more food. But does it help not to waste so much of it? Today, we bring you reports from the two extremes of food waste. Jori Lewis is in the hinterlands of Senegal, among former nomads who herd cattle. Read the full transcript.

So here in the U.S., we’ve got good roads, good electricity and refrigeration. Our farmers stay in one place. But still, we end up wasting a whole lot of food – and the land, labor and resources used to produce it. Marketplace’s Adriene Hill explains. Read the full transcript.

Anchor introduction: The United Nations says by the middle of this century, there are going to be 9 billion people living on this planet. That not-so-simple fact raises a whole lot of questions – not the least of which is how we’re going to feed them all. How are we going to get – as our series this year has been asking – “Food for 9 Billion.” Grow more is the obvious answer. But maybe we’d need to produce less food if we didn’t waste so much of what we have.
So today, two stories of food waste, the extremes of it. In a minute, Marketplace’s Adriene Hill here in California. First, though, Jori Lewis with cattle herders in Senegal.
Reporter Jori Lewis: When I ask Hamadou Seydou Bâ how many cows he has, he says around 70. I know to multiply that number by three, because Fulani cattle herders are notoriously secretive about the numbers. Cows are more than farm animals here; they are the herder’s wealth.
Bâ’s compound is far from the main road, even from a back road. My driver followed a dusty, twisty trail I wouldn’t have known was there.
When we arrived, a small child brought me a bowl of lightly sweetened milk to drink.
The herders use the milk their cows produce. The women make some into butter and some into lait caille, a kind of soured milk – what the child brought me. But there is often too much.
They can’t share it with their neighbors because neighboring herders have their own milk. And the same thing is true at the nearest weekly market. Everyone has milk. And most people in cities, if they drink milk, use powdered milk imported from Europe.
Hamadou Seydou Bâ: When there is a lot of milk, we don’t know what to do with it all. Eventually, we have to throw it out.
Reporter: Djiby Dia is an expert on the milk sector at Senegal’s Agricultural Research Institute. He says 30 percent of the herders’ milk gets thrown out. In regions with a lot of herders, that number can be 80 percent.
Dia says the problem is simple.
Djiby Dia: They are far from the big urban centers, which are the main markets for the milk. And in order to move the milk from the pastoral zone to the capital city, Dakar, we have to have infrastructure and refrigerated trucks, which cost a lot of money.
Reporter: Or do what La Laiterie du Berger did in 2006 – bring a yogurt factory to the herders.
For the Fulani, the yogurt factory is a new source of income to support their traditional life. Hamadou Seydou Bâ was the very first herder to jump on board with the Laiterie du Berger.
Bâ: It can help us. The milk that you used to throw out, now you can sell it and have money to support your family and to buy other food.
Reporter: He does complain the factory hasn’t raised the price it pays to herders. In this drought year, he has sent half his family off with most of the cattle to find new grazing land, keeping only about a dozen cows here. Buying enough feed for just those animals is already too expensive.
But the drought hurts the yogurt factory, too. When so many of its milk producers are nomads who pick up and migrate, it doesn’t have enough milk.
In Senegal, I’m Jori Lewis for Marketplace.
Anchor introduction: We don’t have a lot of the problems here in the States that the Senegalese do. We’ve got good roads, good electricity and refrigeration, and our farmers generally stay in one place. But still, we end up wasting a whole lot of food.
Reporter Adriene Hill: Dairy farmer Brad Scott takes me around his thousand-cow farm, where the cows are pretty much doing what it is cows do.
Brad Scott: Some are resting.
Reporter: Some are eating.
Scott: Some are pretty much hanging out at the water trough.
Reporter: There’s a little mooing.
Scott: And just enjoying a nice day. Their only job …
Reporter: Milk – twice a day.
Scott: So this is what we call the milking parlor.
Reporter: And one of Scott’s workers tugs at each teat to check the milk. These squirts are pretty much all the milk that Scott will toss. And maybe a little that sticks to the walls of the milk tank.
Scott: And other than that, there’s no waste from the time it leaves the udder to the time it gets to the consumer.
Reporter: Here in the U.S., cows and dairy farmers aren’t our food waste problem. Our problem is us. The Department of Agriculture estimates we waste about 30 percent of our milk supply at restaurants and at home. We also waste that much or more of our total food supply – a lot of it without noticing it.
Jonathan Bloom: It tends to just go away.
Reporter: Jonathan Bloom is the author of “American Wasteland.” Where does it disappear to? Here’s a clue: (sound of garbage disposal).
Bloom: We just throw it out, or it goes down the drain and it’s gone, so we don’t think about the impact or the money we’re squandering by the food we’re wasting.
Reporter: We don’t worry too much about tossing the yogurt that’s been sitting a little too long or the abandoned green beans that got a little gooey, because they weren’t that expensive in the first place.
Bloom: Despite rising food prices, the percentage of our household spending that goes to food is at an all-time low, and no other nation spends as little on its food.
Reporter: In the U.S., we waste more fruits and vegetables than any other food group. Milk takes silver in the most-wasted category. And if you really want to see milk-spilling in action …
Tape: Let’s go look at the trash!
Reporter: … Schools are a great place to start.
Tape: This one’s pretty heavy.
Reporter: I visit an elementary school in Ojai, California, and meet sixth-grade teacher Janis Duncan.
Janis Duncan: I’ve dug through a lot of trash.
Reporter: She’s monitored the trash here for five years, discovering whole chicken breasts, apples that were too big for kids to bite into, unopened cartons of milk and …
Duncan: … A lot of yucky stuff, too; a lot of chewed food. When you have it all mashed together, it looks pretty …
Reporter: … I think “gross” is the word. But the amount of trashed food has been declining here. There’s a partnership between the school and a local nonprofit called Food for Thought. To get kids to think more about food waste, they sort their garbage.
Student: Does this go here?
Reporter: The cafeteria staff reminds kids not to take too much. They have a garden with a compost pile.
Student: I want to do it.
Reporter: There’s a sharing table, where kids drop unopened milk. And, says Duncan, they sometimes call on the bigger students to help, giving sixth-graders trash-monitoring duties.
Duncan: I put student leadership at that trashcan and actually had kids make kids drink all their milk before they threw it away. Yeah, and that worked.
Reporter: But kids aren’t the only offenders. A lot of us do the same. Milk spoils in the fridge. We pour it in coffee that we don’t drink. We forget it in the hot car. According to a USDA calculation, we toss the equivalent of about a third a glass of milk per person, per day.
Which, if I do a little math here: 310 million people, ounces into gallons, gallons into pounds of milk, how much cows produce … that’s nearly 800,000 cows’ worth of milk down the drain.
Anchor: Our series “Food for 9 Billion” is a collaboration with Homelands Productions PBS NewsHour and the Center for Investigative Reporting. You can find pictures and other stories by visiting our special collection —“Food for 9 Billion.”