Best Spices for Fajitas: Chile, Cumin, Lime

Fajita seasoning is a short list: chile, cumin, garlic, onion, salt and something sour. America’s Test Kitchen’s weeknight chicken fajitas get by on chili powder, cumin, salt and pepper, with lime juice at the end.¹ And despite what you may have read, ATK’s marinade testing says lime won’t do much to tenderize skirt steak. Read on for what each seasoning brings, how a homemade mix compares with a packet, and safe temperatures for beef, chicken and shrimp.

Where fajitas come from

Fajitas, or arracheras, started out as grilled skirt steak in the ranch lands of South and West Texas, according to Homero Recio’s 1984 study and anecdotal evidence going back to the 1930s.² Skirt steak is the original cut, though McCormick’s packet directions call for chicken breast or beef sirloin.³

At a glance

Seasoning	Job in fajitas	In which named source
Chile (chili powder or pure ground chile)	Heat, color, earthy chile flavor	ATK; USDA spec; McCormick label¹⁴³
Cumin	Warm, earthy note	ATK; USDA spec; McCormick label¹⁴³
Garlic	Savory depth	USDA spec; McCormick label⁴³
Onion	Sweetness when cooked; savory depth	Sliced onion in ATK; onion in the USDA spec and McCormick label¹⁴³
Salt and black pepper	Seasoning	ATK; USDA spec¹⁴
Oregano	Herbal note	USDA spec⁴
Lime (juice or dried)	Sourness	ATK (juice); USDA (lime flavor); McCormick (citric acid, lime juice concentrate)¹⁴³
Paprika	Red color	McCormick label³

The core seasonings

Chile: chili powder or pure chile powder

Two different products share almost the same name. American chili powder is a blend. Saveur describes it as dried chiles, usually ancho, with oregano, cumin, garlic and sometimes salt,⁵ and the USDA’s purchasing spec lists ground chili pepper, cumin, oregano, salt and garlic powder.⁴ A pure chile powder, like ancho powder or chipotle powder, is just one ground chile. Chipotle brings smoke, and Katzer notes the name now means smoked jalapeños almost exclusively.⁶

Either one works in fajitas. ATK uses 1 teaspoon chili powder for two chicken breasts.¹ Go with chili powder and you’ll get some cumin, oregano and garlic along for the ride. See chili powder, paprika vs. chili powder and Mexican oregano.

Cumin

Cumin shows up in all three named sources: ATK uses 1/2 teaspoon ground cumin,¹ and it’s in the USDA spec and on McCormick’s label. PROSEA describes its flavor as strong, warm, pungent and persistent, and notes you only need a little.⁷ See cumin uses and too much cumin.

Paprika

McCormick’s fajita mix lists paprika among its spices.³ It’s there mostly for color. Whether it adds sweetness is a matter of taste, and we didn’t find a source that settles it. See paprika.

Garlic

Garlic is in the USDA spec and on McCormick’s label. Powder is the practical form for a dry rub. ATK notes that garlic powder straight from the jar doesn’t reach its full flavor until water activates it,⁸ so a short rest on the moist meat before cooking gives it that chance. See garlic powder vs. garlic.

Onion

ATK cooks one sliced onion with a red bell pepper alongside the chicken,¹ and onion is in both the USDA spec and McCormick’s mix. Cooked onion adds a bit of sweetness. See onion powder vs. onion.

Salt

ATK puts 1/2 teaspoon salt in the spice mix for the meat.¹ Salting before cooking gives the salt time to work. ATK explains that salt draws out juices that form a brine, and the meat then reabsorbs it.⁹ Packets already carry plenty: McCormick’s fajita mix has 250 mg sodium per 1.5 teaspoons.¹⁰ See table salt and kosher salt.

Lime: flavor, not tenderness

Lime gives fajitas their sour edge, and both the USDA spec and McCormick’s mix build it right into the seasoning. ATK stirs in 4 teaspoons of lime juice off the heat, after cooking.¹

You’ll often read that lime juice tenderizes skirt steak. ATK’s marinade testing says otherwise. Acids like citrus juice do weaken collagen, but only at the surface, and if you leave them too long the outer layer goes mushy. ATK uses acids sparingly and only for short marinating times.¹¹ So for a long marinade, go light on the lime, or add it at the end like ATK does.

Homemade vs. packet

	ATK weeknight chicken fajitas¹	USDA fajita seasoning spec⁴	McCormick Fajita Seasoning Mix³	PepperScale homemade fajita seasoning (batch)¹²
Chile	1 tsp chili powder	Red pepper	Chili pepper, paprika	3 Tbsp chili powder, 1 Tbsp smoked paprika, 1 tsp cayenne
Cumin	1/2 tsp	Yes	Yes	1 Tbsp
Garlic, onion	Sliced onion (cooked with the meat)	Yes	Yes	2 tsp each, powdered
Other spices	Black pepper	Black pepper, oregano	Not itemized	None beyond the blend
Sour element	4 tsp lime juice, added at the end	Natural lime flavor	Citric acid, lime juice concentrate	Optional 1 tsp tomato powder, for color and tang
Also	Salt, cilantro	Salt	Salt, sugar, corn starch	1 Tbsp salt

The USDA list is a minimum (“should include, but is not limited to”), and it calls for a reddish orange, free-flowing blend.⁴ PepperScale’s batch gets its heat from cayenne and smoked paprika and makes about 36 servings. It doesn’t say how much to use per pound of meat. The recipe says to keep the blend in an airtight container for up to 3 months.¹² See fajita seasoning, fajita seasoning substitutes and fajita vs. taco seasoning.

Toppings

Sour cream and Mexican crema both make a cool, creamy topping. Pick whichever you like.

Safe internal temperatures

These come from FoodSafety.gov:¹³

Protein	Minimum internal temperature
Beef steak (skirt, flank, sirloin)	145°F (63°C), then rest 3 minutes
Chicken	165°F (74°C)
Shrimp	Cook until the flesh is pearly or white, and opaque

“Weeknight Skillet Chicken Fajitas”, America’s Test Kitchen, 2013. americastestkitchen.com · Publication ↩ ↩² ↩³ ↩⁴ ↩⁵ ↩⁶ ↩⁷ ↩⁸ ↩⁹ ↩¹⁰ ↩¹¹ ↩¹²
Virginia B. Wood, “Fajita History”, The Austin Chronicle, 2005. austinchronicle.com · Publication ↩
McCormick Fajita Seasoning Mix, product page. mccormick.com · Merchant ↩ ↩² ↩³ ↩⁴ ↩⁵ ↩⁶ ↩⁷ ↩⁸ ↩⁹
Commercial Item Description A-A-20001C, Spices and Spice Blends, USDA Agricultural Marketing Service, 2023. ams.usda.gov · Regulator ↩ ↩² ↩³ ↩⁴ ↩⁵ ↩⁶ ↩⁷ ↩⁸ ↩⁹ ↩¹⁰
“Chili Powder”, Saveur, 2009. saveur.com · Publication ↩
“Paprika and Mexican chiles (Capsicum annuum)”, Gernot Katzer’s Spice Pages. gernot-katzers-spice-pages.com · Reference work ↩
P.C.M. Jansen, “Cuminum cyminum”, PROSEA. uses.plantnet-project.org · Reference work ↩
Carolyn Grillo, “For Great Garlic Bread, Hydrate Your Garlic Powder First”, America’s Test Kitchen, 2021. americastestkitchen.com · Publication ↩
“Salting Meat”, America’s Test Kitchen. americastestkitchen.com · Publication ↩
McCormick Fajita Seasoning Mix, 1.12 oz, ShopRite product listing. shoprite.com · Merchant ↩
“Marinating Myths”, America’s Test Kitchen. americastestkitchen.com · Publication ↩
Matt Bray, Homemade Fajita Seasoning, PepperScale, 2023. pepperscale.com · Publication · PepperScale is also owned by Matt Bray, the editor of this site. ↩ ↩²
“Cook to a Safe Minimum Internal Temperature”, FoodSafety.gov. foodsafety.gov · Regulator ↩

Good Spices for Fajitas: Chile, Cumin, Garlic, Lime and What Each One Does