Blunden 2003 - Tin in canned food review
Blunden and Wallace review inorganic tin migration from tinplate cans into canned foods and beverages, especially products packed in plain internal unlacquered tin-coated steel cans. The source is useful because it collates concentration surveys, tin-dissolution mechanisms, regulatory comparator values, and human acute-effect reports into one peer-reviewed review. Its bottom-line interpretation is that published evidence does not show significant acute gastrointestinal effects from foods containing up to about 200 mg/kg tin, although rare effects at that level cannot be fully excluded and the authors call for better clinical studies.
Key numbers
Regulatory, packaging, and exposure context:
| Parameter | Value | Notes |
|---|---|---|
| JECFA PTWI for tin cited | 14 mg/kg bw/week | Equivalent to 2 mg/kg bw/day in the review |
| Typical maximum permissible tin level, solid foods | 250 mg/kg | UK limit cited separately as 200 mg/kg |
| UK maximum permissible tin level, solid foods | 200 mg/kg | MAFF 1992 |
| Typical maximum permissible tin level, beverages | 150 mg/kg | Codex 1998 cited by the review |
| Food cans produced and filled in Europe annually | about 25,000 million | About 20% with plain internal tin-coated steel bodies |
| Worldwide food-packaging cans annually | about 80,000 million | Tinplate food packaging context |
| Europe tinplate beverage cans annually | over 15,000 million | Internally lacquered according to the review |
| Plain unlacquered cans in UK annually | about 2,500 million | MPMA 2000, as cited in the overview |
| Estimated UK daily tin intake | 2.7 mg/day | 0.04 mg/kg bw/day in Biego et al. 1999, far below PTWI |
| UK TDS estimated tin intake | 2.4 mg/day | Canned vegetables contributed 66%, fruit products 31% |
| Worst-case 1 kg diet with 4%-8% canned foods all at 200 mg/kg | 8-16 mg/day | About 0.13-0.3 mg/kg bw/day for a 60 kg adult |
Tin occurrence in canned foods and beverages:
| Source / matrix | Tin concentration | Notes |
|---|---|---|
| Conserved guava juice | 49.8-59.4 mg/L | Ratana-Ohpas et al. 1996 |
| Conserved lychee juice | 43.9-45.7 mg/L | Ratana-Ohpas et al. 1996 |
| Conserved tomato juice | 59.7-69.7 mg/L | Ratana-Ohpas et al. 1996 |
| Conserved mango juice | 64.3-77.4 mg/L | Ratana-Ohpas et al. 1996 |
| Conserved pineapple juice | 57.8-69.1 mg/L | Ratana-Ohpas et al. 1996 |
| Fresh food | 0.03 mg/kg | Biego et al. 1999 comparator |
| Food in lacquered cans | 3.2 +/- 2.3 mg/kg | Biego et al. 1999 |
| Food in unlacquered cans | 76.6 +/- 36.5 mg/kg | Biego et al. 1999 |
| U.S. grapefruit/orange juice, tomato sauce, pineapple in unlacquered or partly lacquered cans | 51-150 mg/kg | Mean 88 mg/kg, Greger and Baier 1981 |
| UK canned pineapple survey | 50-210 mg/kg | Upper end slightly above the UK 200 mg/kg legal limit |
| UK 2002 canned fruit/vegetable survey | 398 of 400 samples below 200 mg/kg | Two samples above regulatory limit |
| UK 2002 unlacquered-can subset | average 59 mg/kg | 234 food samples in unlacquered cans |
| Plain internal tinplate cans, high-tin share | almost 4% above 150 mg/kg | FSA 2002 / MAFF 2002, as cited |
Tin dissolution and can factors:
| Factor | Reported effect | Notes |
|---|---|---|
| Storage temperature, canned fruit | 420 mg/kg at 37 C vs 34 mg/kg at 1 C | 20 months in unlacquered cans; 12-fold higher at 37 C |
| Storage temperature, mixed dishes | 190 mg/kg at 37 C vs 32 mg/kg at 1 C | 20 months in unlacquered cans; 6-fold higher at 37 C |
| Nitrate in food ingredients | Accelerates detinning | Nitrates from fertilisers are identified as a major oxidizing/depolarizing factor |
| Anthocyanins | May accelerate tin dissolution | Proposed explanation for higher tin dissolution in plum juice than grape juice |
| Plain unlacquered internal tin surface | Higher tin dissolution than lacquered cans | Used for some tomatoes, white fruits, mushrooms, asparagus, and similar foods |
Human clinical and outbreak evidence:
| Evidence type | Tin concentration / dose | Outcome |
|---|---|---|
| Benoy et al. 1971 orange juice challenge, 5 adults | 0, 498, 540, 1,370 ppm tin; or 730 ppm tin plus 50 ppm nitrate | All participants reported nausea and/or diarrhoea at 1,370 ppm; lower concentrations apparently without effect |
| Benoy et al. 1971 re-challenge | 1,370 ppm one month later | Nausea in 1 of 5 participants |
| U.S. Army stored rations, 9 personnel | daily menus 99-310 mg/kg dry solids; average daily tin 162.8 mg | No gastrointestinal effects mentioned; study not designed for GI effects |
| Johnson/Greger adult male diet study | 49.67 mg tin/day for 20 or 40 days | No overt GI effects mentioned; zinc metabolism affected in chronic section |
| Canned pumpkin and asparagus trial | pumpkin 383-476 mg/kg; asparagus 361 mg/kg for 6 days | Four participants; no overt GI effects reported |
| Vegetable juice mixture / citrate buffer secondary report | 700 ppm tin | Nausea and/or diarrhoea in 2 of 8 subjects for vegetable juice; nausea/vomiting or diarrhoea in 3 of 8 for citrate buffer |
| Fruit juice secondary report | 342 mg tin | GI irritation in unspecified volunteers; 125-182 mg had no effect |
| Svensson 1975 canned peaches | fruit 413-597 mg/kg; juice 398 mg/kg | 76 of 85 questionnaire respondents reported nausea, vomiting, or diarrhoea |
| Barker and Runte 1972 tomato juice outbreaks | implicated lots 154-392 ppm; opened cans 131-405 ppm; detinned cans 381-477 ppm | 113 cases across two banquets and family outbreaks; corrosion attributed to nitrate/chlorate |
| Peaches outbreak | fruit 350-600 ppm; liquor 220-440 ppm | Nausea/vomiting in 91 individuals out of unknown exposed population |
| Orange-based drink, Japan | about 425-452 ppm | 1,838 affected in secondary reports |
| Vodka punch with pineapple/grapefruit juice | 2,000 ppm | Severe GI symptoms in 32 people |
| Tinned salmon | 650 ppm | Vomiting, weakness, diarrhoea, or abdominal pain in a family of three |
| Canned rhubarb | 350 ppm | 64 of 127 individuals affected |
Toxicology and kinetics:
| Topic | Value / conclusion | Notes |
|---|---|---|
| GI symptom timing | typically within 15-30 minutes to within 1 hour | Supports local gastric irritation rather than systemic toxicity |
| Review’s acute-effect conclusion | effects observed in limited clinical studies at 700 ppm or above | But no effects also reported in two studies at higher concentrations |
| Inorganic tin absorption | poorly absorbed | Review cites about 2.8% for Sn2+ compounds and 0.64% for Sn4+ compounds |
| Faecal recovery | more than 90% of ingested dose | Humans and laboratory species |
| Chronic element-metabolism signal | about 0.5-1 mg/kg bw/day for extended periods | May alter zinc and other essential-element metabolism |
| Carcinogenicity / genotoxicity / reproductive toxicity | no significant evidence identified | Review separates inorganic tin from organotins |
Methods (brief)
This is a peer-reviewed narrative review, not a new analytical survey. It reviews tinplate packaging chemistry, tin dissolution factors, survey measurements in canned foods and beverages, human clinical challenge studies, outbreak reports, animal acute-toxicity studies, chronic-toxicity evidence, and absorption/distribution/excretion literature. It focuses on divalent inorganic tin dissolved from tinplate cans and explicitly excludes organotin toxicity as irrelevant to tin leached from can interiors.
The occurrence evidence is secondary: the page reports tin values from surveys such as Ratana-Ohpas et al. 1996, Biego et al. 1999, Greger and Baier 1981, MAFF/FSA UK surveys, and total diet studies as summarized by Blunden and Wallace. Because the authors were affiliated with ITRI Ltd, this page assigns B-tier weight despite the peer-reviewed venue and uses the review mainly as a synthesis and pointer to primary sources.
Implications
Certification: This review supports routing inorganic tin risk to canned foods, particularly unlacquered tinplate cans, acidic fruit products, tomato products, and storage-abused cans. Values from the review should not be treated as fresh occurrence measurements from 2003; the strongest routeable figures are the cited survey values and regulatory comparator levels, with the exact source and matrix preserved.
Courses: The review is a useful case study in food-contact migration, showing how pH, nitrate, oxygen/headspace, lacquer integrity, product chemistry, and storage temperature affect metal release. It is also a clean example of speciation discipline: inorganic tin from can corrosion is not interchangeable with organotin compounds from antifouling or plastics pathways.
App: Use this source for consumer-facing explanation that high tin is mainly a canned-food packaging issue, not a typical fresh-food contaminant. Avoid alarmist messaging at or below 200 mg/kg because the review found little evidence of significant acute GI effects up to that range, while still noting that rare effects cannot be ruled out.
Wiki pages this source may touch
- tin
- tin-inorganic
- organotins
- codex-cxs-193-1995-tin-canned-foods
- canned-foods-general
- canned-fruit
- canned-vegetables
- canned-tomatoes
- tomato-paste
- tomato-sauce
- canned-seafood
- canned-fish
- fruit-juices-non-apple
- fruit-juice-not-canned
- canned-tomatoes
- tomato
- tomato-paste
- pineapple
- peach
- peaches
- grapefruit-juice
- asparagus
- canned-mushrooms
- mushrooms
- fruit-juice
- canned-tuna
- tinned-fish
Verification notes
The PDF was read from the June 3 manual-fetch folder, including the abstract, introduction, chemistry/speciation discussion, dissolution factors, occurrence surveys, clinical and outbreak sections, acute animal LD50 table, chronic-effects section, absorption/distribution/excretion discussion, overview, and references. Page count is 12. DOI 10.1016/S0278-6915(03)00217-5 is printed in the PDF metadata and article footer. The raw file raw/Manual Fetch Kimi /June 3 Folder/blunden2003.pdf has SHA-256 9ed5bc29863cd5dbc880b991002a8dc8d6f6638d9b82c0be5015098dbb981342.
Paper-internal arithmetic note: the abstract says a food survey suggested almost 4% of plain internal tinplate food cans exceeded 150 mg/kg and “over 2.5 million” such cans were consumed annually in the UK. The overview later states the UK uses about 2,500 million plain unlacquered cans annually and that even 1% above 150 mg/kg would mean 25 million cans. The overview arithmetic implies roughly 25 million cans at 1% and about 100 million at 4%; this page reports the survey percentage and the overview’s arithmetic framing rather than relying on the abstract’s smaller “2.5 million” figure.
Scope note: the source is a secondary review. It provides no brand-level data and no new sample panel. [[metals/organotins]] appears only as a speciation-separation context page; the review’s routeable canned-food values concern inorganic/total tin leached from tinplate, not organotin contamination.
Page history
The five most recent substantive edits to this page. The full version history lives in git; when DOI minting comes online (see schema docs), each entry below will also link to a version-pinned DataCite DOI.