Cured fish recipeOrigin Recipe

Atún en aceite

Name: Atún en aceite
Total time: 10 d
Yield: 1 kg batch
Cuisine: Charcuterie
Ingredients: 1 kg Tuna loin; 25 g Sea salt

Home-conserved tuna in oil.

Introduction

Atún en Aceite is tuna or bonito gently cooked, separated into clean loins and covered with olive oil. Commercial tins are sterilised shelf-stable preserves; the Curesmith home version is a refrigerated confit and must not be treated as equivalent to industrial canning.

The Curesmith home method

Use 1,000 g very fresh tuna or bonito loin, 18 g salt, 500 g olive oil, 2 g bay and 2 g peppercorns. Maintain the cold chain, cook the tuna to at least 63°C, transfer with clean utensils into a sanitised container, cover with hot oil, cool rapidly and refrigerate. Use within a short validated refrigerated shelf life. For shelf-stable jars, follow a tested pressure-canning schedule from a competent authority.

Where it comes from

Tuna cut chart with the Loin highlighted — Tuna · LoinTuna or bonito loin

Spain, Spain

Before you begin

Purpose and scope

The recipes published on The Curesmith are intended for educational and informational purposes only. Meat curing, fermentation and smoking involve processes that, if carried out incorrectly, can result in products that are unsafe to eat. By using any recipe on this website you acknowledge that you do so entirely at your own risk, and you agree that The Curesmith and its authors cannot be held liable for any outcome arising from its use.

Limitation of liability

The Curesmith and its authors accept no responsibility or liability for any illness, injury, loss or damage arising from the use of these recipes, including but not limited to illness caused by improperly cured, handled or cooked meat products, errors in measurement or technique, equipment failure, or deviation from the stated method or quantities.

Nitrite and cure safety

Meat curing involves the use of nitrite salts, which must be measured accurately and used strictly according to the quantities specified. Nitrite in excessive quantities is toxic. Please ensure you understand the following before proceeding:

Always use a calibrated digital scale accurate to at least one gram. For smaller batches, a scale accurate to 0.1g is strongly recommended.
Never exceed the stated cure amounts. Never substitute cure types without recalculating.
Store all curing salts clearly labelled, separately from regular salt, and out of reach of children.
Different cure products have different nitrite concentrations. Always check your manufacturer's label and adjust quantities accordingly.

Food hygiene and cross-contamination

Raw and cured meat products must be stored, handled and prepared in a clean environment using food-safe equipment. Hands, surfaces, tools and containers must be thoroughly cleaned and where appropriate sanitised before use. Cross-contamination between raw meat and ready-to-eat products must be avoided at all times.

Temperature control

Temperature control is critical throughout all curing and smoking processes. Inadequate temperature management can allow the growth of dangerous pathogens including Clostridium botulinum, Listeria monocytogenes, Salmonella and E. coli. A reliable refrigerator thermometer and a calibrated probe thermometer are essential pieces of equipment for anyone producing cured or smoked meat at home.

Uncooked cured products

Whole muscle products that are eaten without cooking, such as air-dried bresaola, coppa or prosciutto, must reach their target weight loss before consumption. Products that have not been cured and dried to the correct specification may not be safe to eat uncooked. Pancetta and guanciale cured to less than 38% weight loss must not be consumed uncooked.

Bacon and other uncooked cured products

Bacon and other uncooked cured products must be cooked thoroughly before eating. Cold smoking adds flavour and colour but does not cook the product. A cold-smoked bacon or sausage remains a raw product and must reach a safe internal temperature before it is safe to consume. For pork and beef this is 72°C / 162°F. For poultry this is 74°C / 165°F.

When in doubt, seek professional guidance

If you are unsure about any aspect of the curing, smoking or fermentation process, we strongly encourage you to seek formal training or guidance from a qualified food safety professional before proceeding. The information on this website is not a substitute for proper food safety education and training.

Commercial production

These recipes are produced for home and small-scale producers. They are not intended for commercial food production. Commercial meat processing is subject to regulatory requirements that vary by country and jurisdiction. If you intend to produce cured or smoked products for sale, you must ensure full compliance with all applicable food safety regulations in your region.

The recipe

StyleSalt cure (EQ)

Cure time7 days

Before curingFreeze at -20 C (-4 F) for at least 24 hours before curing (parasite control)

Ingredients

Tuna loingAdjust to
scale the recipe

Piece thickness: enter the thickness at the thickest point; it sets the cure time.

mm thickness

Tuna loin
Tuna loin	Reference	1000 g
Cure
Sea salt	2.5%	25 g

Curing timeline

Cure time7 days

Pre-cure freezeFreeze at -20 C (-4 F) for at least 24 hours before curing (parasite control)

Cure temperatureRefrigerated, 2-4 C (36 to 39 F)

Air-drybrine, poach, oil-pack

Ready whenFirm and set through

Method

Clean the fish. Keep the tuna on ice until you are ready to work. Draw the viscera, wash the fish well in cold water, and let the blood drain from the belly cavity.

Precook the tuna. Lay the fish belly-down on a rack in a baking tray, cutting it across into halves if it is large. Bake at 121 C (250 F) for two and a half to four hours, or at 177 C (351 F) for about an hour, until the core reaches 74 to 80 C (165 to 176 F). Steaming for two to four hours does the same work.

Chill overnight. Refrigerate the cooked fish overnight. Resting it cold firms the flesh so it holds together while you clean and pack it.

Skin and bone. Peel the skin away with a knife and lift out any blood vessels and discoloured flesh. Work the meat off the bones, then discard all bones, fin bases and the dark flesh.

Cut to fit. Quarter the cleaned meat and cut the quarters across into lengths that sit neatly in your jars, using half-pint or pint glass jars.

Pack and salt. Press the pieces gently into hot jars to make a firm, solid pack. Season with half a teaspoon of salt per half-pint jar, or a teaspoon per pint.

Cover with oil. Pour in olive oil, or water, to cover the fish, leaving one inch of headspace. Wipe every rim clean of fish oil so the lids can seal.

Process to preserve. Seal the jars and process them under pressure for 100 minutes, at 11 lb on a dial gauge or 10 lb on a weighted gauge. Cool, check the seals, and store.

Key tipsThis is the house equilibrium version at no more than 2.5% salt. Fish safety differs from meat: follow recognised Fish and Fishery Products guidance for histamine and Listeria control.

ImportantThis is cooked before eating: precooked to core by baking or steaming, then the sealed jars are pressure-processed for 100 minutes to make them shelf-stable. Serve it piping hot and cooked right through.

Recipe by The Curesmith — thecuresmith.com

Health & Safety Disclaimer