Similac formula is safe for healthy, full-term infants when prepared and stored correctly. It’s one of the most widely sold formula brands in the United States, and dozens of Similac products are currently listed on the FDA’s registry of approved infant formulas. That said, “safe” comes with real caveats: powdered formula is not sterile, preparation matters more than most parents realize, and premature infants face a specific and serious risk that full-term babies do not.
What FDA Approval Actually Means
Every infant formula sold in the U.S. must meet federal nutrient requirements for calories, protein, fat, vitamins, and minerals before it can legally reach store shelves. Similac currently has over 30 products on the FDA’s approved market list, including standard milk-based formulas, soy-based options, sensitive and gentle varieties, and specialty lines like Alimentum for babies with cow’s milk protein allergy. The FDA does not “approve” formula the way it approves drugs, but manufacturers must notify the agency, demonstrate that their product meets all required nutrient levels, and submit to facility inspections.
The 2022 Recall and What Changed
In February 2022, the FDA investigated four cases of Cronobacter sakazakii infections in infants who had consumed powdered Similac products made at Abbott’s Sturgis, Michigan facility. Cronobacter is a rare but dangerous bacterium that can cause severe bloodstream infections and meningitis in newborns. Inspectors found Cronobacter in five environmental samples collected inside the plant, and Abbott issued a voluntary recall of certain powdered formulas produced there.
The fallout was significant. A federal court entered a consent decree requiring Abbott to complete corrective actions at the Sturgis facility before resuming production. Abbott also committed to enhanced batch testing of stored products before releasing them, a process designed to improve the chances of catching contamination before formula ships. Production eventually resumed under these stricter conditions. No active recalls for Similac products are in place as of early 2026.
The Risk for Premature Babies
The most serious safety concern with Similac, and with cow’s milk-based formula in general, involves premature infants. Necrotizing enterocolitis (NEC) is a potentially fatal intestinal condition that primarily strikes preemies. Their digestive systems are underdeveloped, making it harder to break down the proteins, fats, and carbohydrates in cow’s milk-based formula. Research published in The Lancet found that NEC was six to ten times more common in formula-fed premature babies than in those receiving breast milk, and up to 20 times more common in babies fed exclusively formula.
NEC is fatal in 10% to 50% of cases. When it progresses to complications like intestinal perforation or sepsis, mortality approaches 100%. Babies who survive, particularly those requiring surgery, often face long-term growth and developmental problems. This has led to ongoing lawsuits against Abbott and other formula makers, with plaintiffs arguing the companies failed to adequately warn parents and hospitals about the NEC risk in premature infants. For full-term babies, NEC from formula is extremely rare.
Common Ingredient Concerns
Parents often worry about seeing corn syrup solids on Similac’s ingredient list. Corn syrup solids are not the same thing as high fructose corn syrup. They’re a glucose-based carbohydrate used in formulas designed for babies who have trouble digesting lactose, the sugar naturally found in breast milk and standard milk-based formula. For babies with lactose sensitivity, corn syrup solids provide an alternative energy source their gut can handle. It’s a functional ingredient, not a sweetener added for taste.
Similac’s hypoallergenic line, Alimentum, uses a different approach to protein. The milk protein is broken down into very small fragments through a process called hydrolysis, which virtually eliminates allergic reactions in most babies with cow’s milk protein allergy. Abbott states that Alimentum begins reducing colic symptoms caused by protein sensitivity within 24 hours in most infants.
Preparation Is Where Safety Lives
Powdered infant formula is not sterile. This is true for Similac, Enfamil, store brands, and every other powdered formula on the market. Germs like Cronobacter can be present in the powder itself, which is why how you prepare a bottle matters as much as which brand you choose.
The CDC recommends boiling water and then waiting about five minutes before mixing it with powdered formula. The water needs to be around 158°F (70°C) to kill bacteria like Cronobacter. After mixing, the formula will be too hot to feed immediately. Let it cool and test a few drops on your wrist: it should feel warm, not hot. Always measure the water first, then add powder. Wash your hands, sanitize bottles, and clean your prep surface before every feeding.
Storage Rules That Prevent Bacterial Growth
Once you open a can of powdered Similac, you have four weeks to use it. Write the date on the lid when you open it. Store the can covered in a cool, dry spot (not the refrigerator) at room temperature between 65°F and 75°F. Keep it away from heaters, vents, direct sunlight, and air conditioning units. Never use any formula past its printed expiration date.
Prepared formula, whether mixed from powder or opened from a ready-to-feed bottle, follows tighter timelines. Refrigerate it at 35 to 40°F and use it within 24 to 48 hours. Once your baby starts drinking from a bottle, you have one hour to finish the feeding before that bottle needs to be discarded. Formula left at room temperature for more than one hour should also be thrown out. These rules exist because formula is an ideal growth medium for bacteria, and the vitamins in it (particularly C and B vitamins) begin breaking down once exposed to air and warmth.
Unopened cans and bottles should be stored at room temperature between 32°F and 85°F. If a container has been exposed to freezing temperatures or extreme heat, it’s safest to discard it.
Ready-to-Feed vs. Powdered Formula
If sterility is your top concern, ready-to-feed Similac is the safer format. It’s manufactured under sterile conditions and sealed, meaning it doesn’t carry the same Cronobacter risk as powdered formula. It costs more per feeding, but for newborns under two months, babies born premature, or infants with weakened immune systems, the reduced contamination risk can be worth the price difference. Once opened, ready-to-feed formula follows the same refrigeration and discard rules as prepared powder: use within 48 hours, toss after one hour at room temperature.