Dairy FAQs

Q. How long can you keep milk after the “sell by” date?

A. If properly cared for, milk generally stays fresh for 2 to 3 days after the “sell by” date. For tips on preserving the safety and quality of milk, see the Milk Fact Sheet. For information and tips on other dairy products see the Fact Sheets on cheese, yogurt and other cultured dairy products, ice cream, butter and cream.

Q. How and why is milk pasteurized?

A. All milk intended for direct consumption should be pasteurized – it’s a matter of food safety. Pasteurization is a simple, effective method to kill potentially harmful bacteria without affecting the taste or nutritional value of milk. With standard pasteurization, milk is heated to a temperature of at least 161 degrees Fahrenheit for not less than 15 seconds, followed by rapid cooling. The Newer Knowledge of Dairy Foods contains additional information on pasteurization.

Q. What can I do at home to help protect my family from food borne illness?

A. Individuals and their actions at home play an important role in food safety. To help prevent foodborne illness, food safety experts recommend the following four simple steps:

  • CLEAN: Wash hands and surfaces often with hot, soapy water.
  • SEPARATE: Don’t cross-contaminate. Keep raw meat, poultry and seafood and their juices away from ready-to-eat foods.
  • COOK: Cook to proper temperatures; don’t rely on color alone. Remember to use a food thermometer to check if food is done. Thorough cooking is the most important step in preventing foodborne illness.
  • CHILL: Refrigerate promptly. Growth of harmful bacteria can be slowed or stopped by refrigeration or freezing. The refrigerator temperature should be kept at or below 40 degrees Fahrenheit. The freezer should remain under zero degrees Fahrenheit at all times.

Q. Are all dairy foods antibiotic-free?

A. Yes. In fact, numerous safety measures are in place to help ensure that antibiotics don’t enter the milk supply. For example, a sick cow that is being treated with antibiotics is taken from the milking herd, treated and not put back into the herd until her milk tests free of antibiotics. Additionally, every tank load of milk is strictly tested for antibiotics. Any tanker that tests positive is disposed of immediately, never reaching the public. For more information on milk safety regulations and procedures, see the Dairy Food Safety fact sheet.

Q. What can you tell me about the rbST hormone and milk?

A. All milk, including human breast milk, contains hormones that are digested just as other proteins are digested. While some cows are treated with hormones that are produced by biotechnology, known as recombinant bovine somatotropin (rBST), studies show there is no significant difference between milk from cows that receive hormones and cows that don’t.

The safety of milk from cows treated with rbST has been affirmed by the Food and Drug Administration (FDA), World Health Organization (WHO), American Medical Association (AMA), National Institutes of Health (NIH), American Dietetic Association (ADA) and regulatory agencies in 30 countries.

For more information on rBST, refer to the Dairy Food Safety fact sheet

Q. Is organic milk better for you than regular milk?

A. It’s great to have choices in the marketplace, but there is no difference in the safety or nutrition of organic dairy products compared with conventional dairy products. The U.S. Department of Agriculture (USDA) oversees national standards that food labeled “organic” must meet. According to USDA, organic food is not safer or more nutritious than conventionally-produced food. Organic food differs from conventionally-produced food in the way it is grown, handled, and processed. For more information on organic foods, refer to the USDA’s Certified Organic Program or American Council on Science and Health.

Q. Who should I contact if I have questions about food safety?

A. You can “ask Karen,” the USDA Food Safety and Inspection Service virtual representative. This virtual representative is ready to answer questions from the public on a variety of food safety topics. You also can refer to the government website www.foodsafety.gov.

Food Safety

Food Safety at the Dairy & Grocery Store

The safety of dairy products in the United States is overseen through a cooperative program involving the FDA, state regulators and the dairy industry, which enforces the Pasteurized Milk Ordinance (PMO). This model regulation contains an extensive set of requirements for milk production and processing and is the basis for ensuring the safety of our milk supply. Working with the FDA and state regulators, the nation’s dairy industry ensures that milk is produced and processed in a safe and sanitary manner and leaves their facilities free of any possible disease causing organisms.

Testing each load of milk

Every single shipment of milk that enters a dairy processing plant is tested for a variety of safety and quality factors. Any milk that does not meet these stringent standards is immediately discarded and the farm that is the source of the milk is identified and financially responsible for the cost of the entire shipment. According to the most recent studies, less than 0.1% of all shipments do not meet federal standards. In addition to this regular testing regimen, federal, state and local regulatory agencies make frequent and unannounced on-site inspections of dairy processors and dairy farms.

The importance of pasteurization

French doctor and scientist Louis Pasteur invented the process of pasteurization more than a century ago. Since its discovery, pasteurization has safeguarded much of our food supply, including milk and dairy products.

By heating the incoming refrigerated raw milk in specially-designed equipment, pasteurization ensures the safety and wholesomeness of the product while not affecting the quality or taste of the milk. Once pasteurized, milk and milk products are then routinely tested for product quality and safety. Most fluid milk in the United States is required to be pasteurized, and if it’s not pasteurized, it’s required to be labeled as raw milk. Most domestic fresh and soft cheeses are also pasteurized. Hard cheeses aged longer than 60 days do not require pasteurization.

For more information on pasteurization, click here.

Rapid Cooling

Once it has been pasteurized, milk is rapidly chilled to between 38 and 40 degrees Fahrenheit until it is packaged. This rapid cooling helps to keep the milk as fresh as possible. To maintain freshness, milk is constantly refrigerated until the consumer puts it in his or her shopping cart. Similarly, milk should be refrigerated at home until it’s ready to be used.