Rio Mare Tuna: What Is in the Tin, and What the Oil Is Doing
Rio Mare tuna is one of the few supermarket tins whose ingredients list is short enough to read in a single glance, and the interesting word in it is "olive oil". That phrase does a lot of work on a tuna tin. It changes the texture, it dominates the nutrition panel on the back, and it is one of the clearest dividing lines between the Italian canning tradition and the brine-and-sunflower default most British shoppers grew up with. It is also, on this brand, not applied evenly across the range. We read every ingredients panel Rio Mare publishes on its own UK and Italian sites on 28 August 2026, and this is what they say.
For our own oil, see our cold-pressed organic Marrakech olive oil. We do not sell tinned fish of any kind.
The Short Answer
- Rio Mare is an Italian canned-fish brand owned by Bolton Food S.p.A., part of Bolton Group S.r.l. of Via G.B. Pirelli 19, Milan — as stated in the footer of the brand's own UK site.
- Every tinned tuna product in the UK range is packed in olive oil. The UK site lists twelve products across four lines, and the whole-fish ones are in olive oil or extra virgin olive oil. There is no brine or spring-water tuna in the UK range at all.
- The core recipe is three ingredients. Tuna in Olive Oil 160g reads, in full: "Tuna*, Olive Oil, Salt", with the species given as Euthynnus (Katsuwonus) pelamis — skipjack.
- The oil is not evenly applied across the range. The prepared lines are a different story: the UK Insalatissime salads are made with corn oil, and on the Italian site the tuna pestos use sunflower seed oil and the paté uses corn oil.
- The packing medium dominates the nutrition panel. Rio Mare's own figures: the olive oil tuna is 37 g fat per 100 g of whole product; the Italian water-packed Tonno al Naturale is 0.5 g per 100 g drained.
- Species varies by line and by market. The Italian classic tin is yellowfin, Thunnus albacares; the UK tin of the same name is skipjack. Both are printed on pack.
- "Olive oil" on a tin is a category, not a specification. It does not tell you the grade, the origin, the harvest year or how the oil was made — which is exactly the gap we spend our time on in the oil aisle.
Who Rio Mare Is
Rio Mare is an Italian brand of canned and jarred fish, sold across most of Europe and in Canada, the United States, South Korea and the Middle East — the country selector on riomare.com listed twenty-nine markets when we checked. The UK site is riomare.co.uk. Corporate ownership is stated plainly in the site footer: Bolton Food S.p.A., within Bolton Group S.r.l., registered at Via G.B. Pirelli 19, 20124 Milan.
What is worth crediting straight away is the labelling. Rio Mare prints the species as a Latin binomial against an asterisk in the ingredients list on every product page we opened, in both markets. A great many canned tuna brands say "tuna" and stop. Naming Thunnus albacares or Katsuwonus pelamis is a real disclosure, and it is the kind of specificity we would like to see far more of on olive oil labels.
What the UK Range Actually Contains
The UK product sitemap lists twelve products across four lines: Tuna, Tuna Fillets, Flavoured Tuna and Insalatissime Tuna Salads. We opened the ingredients panels. Here is what they say.
| UK product | Ingredients as published | Packing medium | Species named on pack |
|---|---|---|---|
| Tuna in Olive Oil 160g | Tuna*, Olive Oil, Salt | Olive oil | Euthynnus (Katsuwonus) pelamis |
| Tuna Fillets in Glass Jar with Olive Oil | Tuna Fillets*, Olive Oil, Salt | Olive oil | Euthynnus (Katsuwonus) pelamis |
| Tuna in Extra Virgin Olive Oil | Tuna*, Extra Virgin Olive Oil, Salt | Extra virgin olive oil | Euthynnus (Katsuwonus) pelamis |
| Tuna in Olive Oil with Italian Chilli | Tuna*, Olive Oil, Salt, Chilli (origin: Italy) 0.1%, Chilli 0.1%, Flavourings | Olive oil | Euthynnus (Katsuwonus) pelamis |
| Insalatissime Tuna & Sweetcorn Salad | Sweet Corn 29%, Tuna* 19%, Corn Oil, Carrots 11%, Peas 11%, Black Olives 3%, Lemon Juice, Salt | Corn oil | Euthynnus (Katsuwonus) pelamis |
| Insalatissime Mexican Style Tuna Salad | Tuna* 19%, Red Beans 23%, Sweet Corn 20%, Corn Oil, Peppers 6%, Carrots 6%, Salt, Flavourings | Corn oil | Euthynnus (Katsuwonus) pelamis |
Skipjack throughout, in other words, across the whole UK range — and olive oil in every tin that is simply fish.
The retail picture matches. Tesco's own grocery listing returned three Rio Mare products when we searched it on 28 August 2026 — Tuna in Olive Oil 160g, Tuna in Olive Oil MSC 3x80g, and Tuna Fillets in Olive Oil 180g MSC — with two of the three carrying MSC certification in the listed pack name. No brine variant appeared.
Where the Olive Oil Stops
This is the range nuance, and it is the sort of thing a brand page will never volunteer. On the Italian site the catalogue runs to twelve categories, and the packing medium changes as soon as the product stops being fish in a tin and starts being a prepared dish.
| Italian line | Oil named in the ingredients list |
|---|---|
| Tonno all'Olio di Oliva; Tonno «filod'olio»; Tonno Pescato a Canna | Olive oil |
| Trancetti (vacuum-packed steaks) | Olive oil, 15% |
| Filetti di Tonno all'Olio di Oliva | Olive oil |
| Sardine all'Olio d'Oliva | Olive oil |
| Filetto di Salmone all'Olio d'Oliva | Olive oil, 19% |
| Filetti di Sgombro Grigliati | Extra virgin olive oil, 10% |
| Per Pasta alla Puttanesca | Olive oil 17% and extra virgin olive oil 6% |
| Tonno al Naturale; Tonno Super Naturale | None — water, salt, natural celery and onion flavouring |
| Insalatissime; Con Gusto; Paté di Tonno | Corn seed oil |
| Pesti al Tonno | Sunflower seed oil |
None of that is a criticism. A tuna pesto is a sauce, and a neutral seed oil is a defensible choice in a sauce where basil and pecorino are meant to carry the flavour. The point is narrower and more useful: "Rio Mare" is not a synonym for "packed in olive oil", and the only way to know which tin you have is to turn it over.
The species shifts too. The Italian Tonno all'Olio di Oliva and Tonno al Naturale are yellowfin, Thunnus albacares; the Trancetti, the Filetti and the whole UK range are skipjack. The paté names both.
What the Packing Medium Actually Does
Oil packing does three things: it excludes air, it carries fat-soluble aroma out of the fish and back into it, and it stops the flesh drying as it cooks inside the sealed tin. Water packing does the first only. That is why an oil-packed tin tastes rounder and a water-packed one tastes cleaner and firmer — and it is why the nutrition panels look nothing alike.
Rio Mare publishes both, so the comparison is theirs rather than ours.
| Per 100 g, as published by Rio Mare | Tonno all'Olio di Oliva | Tonno al Naturale | Trancetti, olive oil 15% |
|---|---|---|---|
| Fat | 37 g | 0.5 g | 16 g |
| of which saturates | 6 g | 0.2 g | 2.7 g |
| Protein | 17 g | 24 g | 24 g |
| Salt | 1.1 g | 1.1 g | 1.2 g |
| Species named on pack | Thunnus albacares | Thunnus albacares | Katsuwonus pelamis |
| Basis of the figures | Whole product, undrained | Drained product | Whole product, undrained |
That last row matters more than any number above it. The olive oil figures are given for the whole tin including the oil; the al naturale figures are given drained. Comparing 37 g against 0.5 g is not comparing two pieces of fish — it is comparing a tin with its oil against a tin without its water. Drain the oil tin and most of that fat goes down the sink with it. Whether you should drain it is a matter of what you are cooking, not of virtue.
The other honest observation is that the oil in the tin is a real ingredient. Using it in the pan is the traditional Italian approach, and it has spent months absorbing the fish. Tipping it away is a legitimate choice; so is keeping it.
"Olive Oil" or "Extra Virgin"? What the Two Words Commit To
Rio Mare uses both, deliberately and separately: most tins say olive oil, one UK line says extra virgin olive oil, and the Italian grilled mackerel says extra virgin at 10%. Those are different products in law.
Extra virgin is a defined grade with numbers behind it — free acidity, peroxide value, ultraviolet absorbance and a sensory panel median, set out in the International Olive Council trade standard and mirrored in EU law. "Olive oil" as a plain label term, by contrast, is normally a blend of refined olive oil with some virgin oil added back, and no sensory panel is involved. Neither is dishonest. They are simply different specifications, and a brand that distinguishes between them on the label is telling you something true.
What no tin tells you is which olive oil: the country of origin, the harvest year, the cultivar, or the polyphenol content. That is not Rio Mare's failing — no canned fish standard requires it. It is just the point at which the tin stops being informative, and it is the same point at which most olive oil bottles stop being informative too. For what a bottle can genuinely tell you, see our guide to choosing a quality olive oil, and for the difference between the grades in the first place, our explainer on what extra virgin olive oil is.
The Objections Worth Taking Seriously
"You sell olive oil, so of course you like the olive oil tins." Fair, and worth naming. We sell a 500 ml bottle of extra virgin olive oil for a kitchen; nobody is choosing between that and a tin of tuna. We have no product in this category and nothing to gain from you preferring one packing medium to another. What we do have is a professional interest in what the words "olive oil" are asked to mean on packaging, and this is an unusually clean example.
"Isn't the oil version just worse for you?" We are not going to answer that, because it is a nutrition question about a food and we are not the people to settle it. What we can say factually is that the two panels are drawn on different bases — one whole, one drained — and that comparing them straight is misleading. If you are managing your fat or salt intake for a medical reason, that is a conversation for a GP or a registered dietitian, not a blog.
"Does any of this actually matter?" Only if you care what you are buying. A tin that lists three ingredients and prints the Latin name of the fish is more informative than most things on a supermarket shelf, and it is still silent on the origin and grade of a substantial part of its contents. That gap is not a scandal. It is the ordinary state of food labelling, and it is worth seeing clearly.
Why Sidr & Stone
Our interest in a tuna tin is narrow and slightly odd: it is one of the few places where olive oil is sold to people who are not thinking about olive oil at all. Whatever is in that tin was bought in bulk, judged on price and stability, and described in two words. Our own oil goes the other way.
- Single-estate — one family-owned grove on the plains outside Marrakech, Morocco, with no blending across origins.
- Rain-fed — no irrigation; the trees take what the season gives them.
- Organically grown — no synthetic fertilisers, pesticides or herbicides. We do not hold a formal organic certificate and we do not claim one.
- Single harvest — a small batch, once a season, picked when the fruit is ready rather than when the calendar says so.
- Cold-pressed within hours of harvest — flavour, aroma and polyphenols preserved by keeping the gap between picking and pressing short.
- Unfiltered extra virgin — minimally processed, and it may show natural sediment, which is normal for an unfiltered oil.
- 100% natural — one ingredient, and nothing added to it.
- 500 ml dark glass with a gold label — protective packaging in a size built to be finished fresh.
- Halal certified, with 10% of profits to charity as a brand-wide commitment.
- Fulfilment in the UK, EU, and US.
We will not tell you Sidr & Stone is the best olive oil — that would be exactly the sort of unbacked adjective this article is about. We publish no polyphenol figure for our oil yet, and we say so rather than implying one. What we will say is where it comes from, how it was made, and when. For the wider story of what a single origin commits a producer to, see our piece on single-estate olive oil.
Frequently Asked Questions
What oil is Rio Mare tuna packed in?
Olive oil, on every tinned tuna product in the UK range, and extra virgin olive oil on one line. The Italian range adds water-packed tins under the al naturale name. The prepared products are different: Insalatissime salads and the paté use corn oil, and the tuna pestos use sunflower seed oil.
Is Rio Mare tuna in extra virgin olive oil?
One UK product is. "Tuna in Extra Virgin Olive Oil" lists Tuna*, Extra Virgin Olive Oil, Salt. The other tins say olive oil, which in labelling terms is normally a blend of refined and virgin oil rather than the extra virgin grade.
What kind of tuna does Rio Mare use?
It is printed on the pack. The whole UK range names Euthynnus (Katsuwonus) pelamis, skipjack. The Italian Tonno all'Olio di Oliva and Tonno al Naturale name Thunnus albacares, yellowfin. The Italian paté names both species.
Should you drain the oil from a tin of tuna?
It depends what you are making. The oil carries flavour out of the fish and back into it, and using it is the traditional Italian approach in pasta sauces. Draining it removes most of the fat that appears in the whole-product nutrition figures. Both are reasonable.
Why is the fat figure so high on the olive oil tins?
Because Rio Mare publishes those figures for the whole product including the packing oil, while the water-packed figures are given for the drained product. The two are not measured on the same basis, so reading 37 g against 0.5 g as a like-for-like comparison overstates the difference.
Who owns Rio Mare?
Bolton Food S.p.A., part of Bolton Group S.r.l., which gives its registered address as Via G.B. Pirelli 19, 20124 Milan. Both are named in the footer of Rio Mare's own UK website.
Does the tin say where the olive oil comes from?
No. The ingredients list names the category — olive oil or extra virgin olive oil — and nothing beyond it. No origin, harvest year, cultivar or polyphenol figure appears, and no canned fish standard requires them to.
Is olive oil a medicine?
No. Olive oil is a food, not a medicine. It has a long traditional history — including being honoured in the Prophetic Sunnah — and a substantial body of modern research, particularly around polyphenols, cardiovascular health, and the Mediterranean diet pattern. It can be a worthwhile part of a healthy routine, but it does not cure diseases and is not a substitute for medical care. Be cautious of any olive oil marketed with specific disease-cure claims.
Final Thoughts
Rio Mare's core tin is an unusually honest object. Three ingredients, the species in Latin, and the packing medium named on the front rather than buried. Against most of a supermarket, that is a high standard, and it deserves saying without qualification.
The interesting part is where the disclosure stops. Olive oil is a substantial part of what you are buying by weight, and it is described in two words that could cover an enormous range of oils from an enormous range of places. That is not a defect in this brand; it is the ordinary limit of an ingredients list. But it is a good reminder that the word on the pack and the specification behind it are different things, and that only one of them is a promise.
That gap is the whole of our own work. Our cold-pressed organic Marrakech olive oil — single-estate, rain-fed, organically grown and unfiltered — names its grove, its season and its method, and it is available to pre-order, with fulfilment in the UK, EU, and US. First harvest, estimated shipping from November 2026.
Pre-Order Sidr & Stone Organic Marrakech Olive Oil — Limited First Harvest →
Disclaimer: This article describes ingredients lists, nutrition figures and range composition published on Rio Mare's own UK and Italian websites and read on 28 August 2026; recipes, ranges and published figures change, and readers should always check the pack in front of them. References to Rio Mare, Bolton Food and Tesco describe general product and retail observations and are not affiliated with or endorsed by those companies. Comparisons are made in good faith and in fair terms. Olive oil is a food, not a medicine, and is not a substitute for medical treatment of any condition. For any health concern, consult a qualified medical professional.