The five most common chemicals found in modern food

Ultraprocessed foods include preservatives, dyes, sweeteners, and more

Processed foods are those that have been altered from their original state, which includes numerous processes that we consider natural, such as cooking or salting. Ultraprocessed foods contain at least one item that wouldn’t be found in a kitchen, like hydrogenated oils or high-fructose corn syrup. It’s estimated that nearly 75% of all foods consumed in the US are ultraprocessed, though that doesn’t mean that all of them are unhealthy. In fact, some, such as prepackaged whole wheat bread and soy milk, are recognized for their health benefits.

The amount of plastic chemicals in 300 everyday Bay Area foods

Food production is more complicated than it appears, and manufacturing, packaging, and shipping processes can add significant substances to your food. This massive project compiled data on 300 samples of foods delivered to the San Francisco area, testing for the presence of 18 different kind of plastic. Learn how to read the data here with its helpful guides and then explore the table yourself.

Ultraprocessed foods are linked with a 58% elevated risk of developing dementia.

Most of the 86,000 consumer chemicals registered with the US EPA have never received rigorous toxicity testing, though not all those are still in current use.

Used since the 1940s, 'forever chemicals' include thousands of different types of substances routinely integrated into industry and consumer products, yet research suggests they can accumulate in the body over time.

Why processed foods can be so addictive

In recent years, many critics have voiced their concerns about the food industry and how ultra-processed foods affect our health. Despite our awareness of these issues, processed foods are still incredibly hard to remove from our diet. In this podcast by The Guardian, Dr. Chris van Tulleken explains how “junk food” is created to get us hooked, how it negatively affects us, and what we can do to improve our eating habits.

Forever chemicals accumulate up the food web, with recent research indicating that apex predators have higher concentrations because they're eating prey that also have accumulated the substances.

Explore the chemical compounds found in fireworks

Besides the various salts and metals used to produce fireworks colors, shells are also filled with gunpowder and oxidizers to help fuel and accelerate reactions. Chlorates help strengthen colors, while dextrin, a starch, helps hold mixtures together.

Molecules derived from algae can be found in foods such as ice cream, salad dressings, brownie mix, and gravies, as well as in products such as toothpaste, multivitamins, and egg substitutes.

The research that led to sour

Scientists are trying to figure out if there are unique receptors that respond to the molecules that make up flavors we associate with calcium, blood, batteries, and other items that often escape dinner menus. Taste researcher Dr. Danielle Reed says the minimum evidence for a taste category typically involves identifying dedicated receptors and then removing them to show the taste vanishes.

Learn the history of food science breakthroughs from the 20th century

Long after humans developed the means to produce sufficient food to feed civilizations, scientific research focused on a wide variety of objectives, such as developing methods to preserve food quality (accomplished via frozen food), speeding up cooking (leading to the microwave), and lowering the cost of sweetening food, which high fructose corn syrup provides.

Ultra-processed foods are made to maximize cravings and encourage overeating

Often disguised as healthy options like granola bars and low-fat yogurt, these foods silently fuel chronic diseases, despite dominating diets. Reviewing labels for ingredients like stabilizers and emulsifiers can serve as indicators to help identify these products.

Watch 'Last Week Tonight' explore the risks of 'forever chemicals,' a group of human-made chemicals used in everyday products to make them resistant to water, stains, grease, and heat. (Warning: language.)

Proof of 'natural' food claims are voluntary for most food products

Unlike the enforcement done by the USDA for meat, dairy and eggs, the FDA offers loose guidelines for using a "natural" food label on most foods, and following the guidelines is voluntary. As a result, many products labeled as "natural" can contain processed ingredients and synthetic additives.

More than 90% of America's food allergies are triggered by 9 foods.

BPA-free plastics may still pose health risks because they often contain other structurally similar chemicals.

How five of the world's most expensive salt and spices are made

Part of the charm of certain spices and salts is their exotic origin, hailing from difficult-to-access locales or hewn via special processes. That also explains why they can be so expensive. Dive into the businesses of producing and marketing five of the world's most expensive food additives with this engaging video.

Learn about the seven types of plastic, including their recyclability, toxicity, health risks, and common uses.

Why bacterial bioremediation may help counter the negative effects of past chemical solutions

Molecules such as DDT, a synthetic insecticide, and PFAS—"forever" chemicals used to make products resistant to heat, water, and grease—have historically been used across various industries but are now known to be harmful. Microbes that can convert some of these substances into nontoxic products, such as water and carbon dioxide, have already been identified, with ongoing research to find others.

Forever chemicals are so common that experts concluded in 2022 that it's uncertain whether limiting consumer exposure would truly reduce one's exposure to these substances, and noted it would still take years for the body to clear them.

See this interactive global map that highlights which forever chemicals have been detected in specific wildlife species, providing data on hundreds of species exposed to these hard-to-breakdown substances.

Teflon was an accidental discovery by a DuPont scientist in the 1930s resulting from efforts to create a safe refrigerant.

Ammonium may be the sixth basic taste

Researchers have proposed various candidates for the sixth official taste, including "fat." But research published in 2023 posits that ammonium should be considered the sixth taste since they found humans can apparently detect ammonium chloride, which the scientists describe as "bitter, salty, and a little sour." Detecting ammonia could be a survival mechanism to help detect when certain foods, including seafood, are no longer safe to eat. The work hinged on experiments with human cells exposed to ammonium chloride as well as rodent research.

Listen to how the 1902 'poison squad' experiments changed food safety in America

As part of government research, a group of young men were paid to eat standard American food—replete with food additives like borax and formaldehyde—which revealed the dangers of unregulated food. The work was led by the first FDA commissioner, Harvey Wiley, who helped end the "century of the great stomachache."

Supplements often have issues with impurities, toxins, and inaccurate labels

Consumer Reports' tests of more than 20 supplement powders and shakes in 2025 found that more than two-thirds of them contain unsafe levels of lead. Some contained 10 times the amount of lead that's considered acceptable to ingest in a day. The levels they found, in some cases, were even higher than when they tested the products 15 years earlier.

The history of molecular gastronomy, from thickening yolks with alcohol to making art with food

Before understanding why they worked, humans used scientific principles, including designing solutions and analyzing outcomes, to develop preservation methods like curing meat and fermenting vegetables. By the 20th century, the application of industrialized food preparation to smaller kitchens set the stage for the subdiscipline of food science.

View a sample of objects surprisingly derived from crude oil, including chewing gum and lipstick

Crude oil processing produces a variety of fuels and the building blocks for plastics, but it also distills out the hydrocarbons used to make aspirin, Teflon, vinyl, crayons, candles, Tupperware, roofing shingles, asphalt pavement, hair dye, anesthetics, food-grade lubricants, polyester, synthetic rubber, and resins for items like dentures.

The importance of volatile aroma compounds in the flavor quality of food

Processes such as air movement and heating cause food to lose aroma molecules, which studies have shown play a major role in our sense of taste. While losing these molecules to the environment leaves fewer to be processed during consumption to intensify flavor, it can also produce previously nonexistent aroma compounds or release previously trapped ones, altering or enhancing the food's flavor.

One in six Americans contracts food poisoning each year.

World War II helped convince food companies to produce more processed foods

Processed foods had existed since the 19th century, but they began infiltrating the mainstream during World War II, with foods designed to last on the battlefield for days. After the war, food companies saw great potential in the relatively cheap foods aimed at busy households. (Some readers may experience a paywall.)

Monosodium glutamate is a sodium salt form of a naturally occurring amino acid

Monosodium glutamate myths originate from a 1968 letter to the New England Journal of Medicine, in which unpleasant symptoms after eating Chinese food were dubbed Chinese restaurant syndrome without medical data. Subsequent studies show this savory flavor enhancer—found in tomatoes, mushrooms, and other foods—is safe in moderation.

Multiple sugar substitutes were accidental discoveries when lab workers didn't wash their hands.

Discover the chemistry behind smoking foods, including the types of smoking and the source of smoking flavors and colors.

A brief explainer on food expiration dates and what they really mean

Roughly 20% of food items in the US are thrown out because consumers don't understand how to interpret expiration labels. Over time, when supermarkets began carrying processed foods, grocers use packaging codes to track how long foods had been on...

How fermentation enables the pickling of food and the production of beer

This process occurs when microbes produce lactic acid, ethanol, or carbon dioxide after consuming sugars. The acid helps preserve vegetables in a brine solution during pickling and gives them a sour taste, while ethanol serves as the inebriant in alcoholic beverages. The acid and carbon dioxide give sourdough bread its taste and texture.

Taste buds have evolved to fill a wide variety of functions

Taste buds do more than let you experience your favorite food. These peripheral organs can sense the chemical makeup, potential toxicity, and fleeting experience of flavor, giving the body a chance to respond to undesirable chemicals or tell the brain that you should reach for another scoop.

The flavor of food can be enhanced by combining chemicals known to trigger umami taste receptors with nucleotides—building blocks of DNA and RNA—triggering an effect called umami synergy.

A breakdown of gelling agents used to modify a liquid's texture

Gelatin, agar, and other substances form a structural network that traps liquid, making it appear solid and enabling chefs to create stable layers in pastries and confectionery products. In different concentrations, they can also be used to thicken liquids into gels or encase them in gelatinous spheres.

Microplastics are entering human food chains through carrots, wheat, and other foodstuffs grown in farmlands fertilized by sewage sludge.

How silica gel took over the world

Silica gel packets are those sugar packet-like bags that keep packaged foods and more dry and free of mildew. First invented in the early 20th century, they saw great commercial success starting in 1927, being deployed in traded goods across the world. This simple invention allows modern supply chains to extend across the globe by extending the preservation of shipped goods.

Carboxylic acids are one reason teens are smelly

Scientists compared the smells of babies and teenagers and identified some of the compounds that make teens smelly. Carboxylic acids present in teens, they wrote, seemed to give off an "earthy, musty, or cheesy" scent. This 2024 research could help inform future odor-control products.

Rising fracking rates have increased prices of some food products

Every fracking well uses approximately 20,000 pounds of guar gum, a thickening and stabilizing agent commonly used in ice cream, salad dressing, and baked goods. The polysaccharide is also a key component in some cosmetics and explosives.

How understanding a balanced diet can help you make good food choices

Eating a balanced diet—which includes a variety of foods from all food groups—is important for optimal health. It is also recommended to avoid ultra-processed foods, such as frozen meals, fast foods, soda, and flavored yogurt. The simplest way...

How the methods of catching fish for food affects their taste

Commercially caught fish are often killed through suffocation, allowing the causing the fish extreme stress and flooding their bodies with stress hormones and lactic acid. These chemicals cause the fish's flesh to become bitter where it was once rich and quickens the rotting process.

Mycotoxins are toxic compounds produced by fungi—some show up in food

About a quarter of the world’s agricultural products are contaminated with mycotoxins. Some of these compounds can cause serious health problems, including cancer, so the US government has set up monitoring programs to detect them in our food and in animal feed. Humans can become ill if they eat contaminated food, but also if they ingest products from animals that had previously consumed these toxic compounds, such as milk from a cow that ate contaminated corn.

Processed foods were marketed to busy wives in the 1950s

In the 1950s, they were marketed as time-saving conveniences for young families, especially those living in the rapidly expanding suburbs, who could easily find them in local supermarkets, making them a seemingly sensible alternative to fresh foods.

MSG was first isolated from seaweed in Japan in 1908

The compound monosodium glutamate has been identified in dairy, meats and vegetables, and provides an "umami"—Japanese for "tasty"—flavor to food. Studies in the late 1960s characterized MSG as harmful, but only when testing doses hundreds of times greater than what would be consumed in a typical diet.

The food processing techniques developed for World War II, later repurposed for consumers

Research projects funded or sponsored by the military led to the development of active dry yeast to make bread easier to bake and an improved version of dehydrated cheese, which would be used in powdered cheese snacks. Freeze-drying, which had been used to ease the transport of blood plasma to battlefields, where it would be reconstituted with water, was later used on fruit for cereals.

Food companies usually issue recalls voluntarily and you can be automatically notified about them

Protecting yourself from food poisoning means staying on top of food recall announcements. Notices about these from the US government, which you can automatically receive after signing up at this link, note what products have been recalled by food companies. Companies alert the US Food and Drug Administration or the US Department of Agriculture when they issue recalls so the public can stay informed.

The science of food allergies

Why do certain substances trigger an immune response while others don't? Listen to researchers explain the science in this five-minute video. Food allergies affect around 8% of children and 2% of adults in the US, and—unlike sensitivity or intolerance—they involve the immune system mistaking certain harmless proteins in foods as dangerous invaders, triggering a rapid and sometimes severe defense response.