Fact-checked by Grok 2 weeks ago

Sulfite

The sulfite ion (SO₃²⁻) is a sulfur oxoanion and divalent inorganic anion that functions as the conjugate base of hydrogen sulfite, featuring a central sulfur atom coordinated to three oxygen atoms with a 2− charge.^[1] This ion exhibits a trigonal pyramidal geometry arising from three σ-bonds and a lone pair on the sulfur atom, analogous to ammonia, while its electronic structure involves resonance delocalization of the negative charge and a formal double bond across equivalent sulfur-oxygen linkages.^[2] Sulfite salts, such as sodium sulfite, are employed as antioxidants and preservatives in the food industry to prevent enzymatic browning, microbial spoilage, and oxidation in products like dried fruits, wines, and processed meats, as well as in industrial applications including pulp bleaching and water treatment.^[4]^[5] In aqueous media, sulfites undergo hydrolysis to form basic solutions and equilibrate with bisulfite (HSO₃⁻) and sulfur dioxide (SO₂), enabling their role as reducing agents but also contributing to their instability in air, where they oxidize to sulfate (SO₄²⁻). Notably, sulfites can provoke adverse reactions in susceptible individuals, particularly asthmatics, including bronchoconstriction, urticaria, flushing, and anaphylactic symptoms, prompting regulatory labeling requirements for foods containing them above threshold levels.^[6]^[7]^[8]

Chemical Properties

Molecular Structure and Bonding

The sulfite ion (SO₃²⁻) consists of a central sulfur atom bonded to three oxygen atoms, forming a trigonal pyramidal anion with C_{3v} symmetry. According to valence shell electron pair repulsion (VSEPR) theory, the geometry arises from four electron pairs around sulfur—three bonding pairs and one lone pair—adopting a tetrahedral electron arrangement that distorts to pyramidal molecular shape.^[9]^[10] Bonding in SO₃²⁻ involves resonance delocalization across three equivalent structures, each featuring two S–O single bonds, one S=O double bond, and the negative charges distributed on oxygen atoms, leading to identical S–O bond lengths averaging approximately 1.49 Å as observed in X-ray crystallographic studies of sulfite salts.^[10] The O–S–O bond angles measure about 106°, reflecting lone pair-bond pair repulsion that compresses the angles below the ideal tetrahedral 109.5°.^[11] In common sulfite salts such as sodium sulfite (Na₂SO₃), the structure is ionic, comprising Na⁺ cations and pyramidal SO₃²⁻ anions arranged in a trigonal crystal lattice (space group P̅3).^[12] Potassium metabisulfite (K₂S₂O₅) features the metabisulfite anion (S₂O₅²⁻), which differs structurally from SO₃²⁻ by incorporating two sulfur atoms linked via an S–S bond, with one SO₃ subunit bearing the charge localization and an adjacent SO₂ group, as confirmed by crystallographic analysis.^[13] The bisulfite ion (HSO₃⁻), often in equilibrium with sulfite under acidic conditions, maintains a pyramidal core similar to SO₃²⁻ but with a proton attached to one oxygen atom, yielding C_s symmetry and distinct bond lengths due to the O–H formation and charge reduction.^[14] Spectroscopic evidence, including ¹⁷O NMR, supports the predominance of the O-protonated form in aqueous solutions, highlighting differences in electronic distribution compared to the symmetric sulfite ion.^[14]

Physical Characteristics and Reactivity

Sulfite salts, such as sodium sulfite (Na₂SO₃), typically manifest as white, odorless crystalline powders or solids with a sulfurous taste. Anhydrous sodium sulfite possesses a molar mass of 126.043 g/mol and a density of 2.633 g/cm³, rendering it denser than water where it sinks and dissolves slowly.^[15]^[16] These compounds exhibit high water solubility, with sodium sulfite achieving approximately 30.7 g dissolved per 100 g of water at ambient conditions.^[17] Upon heating above 150°C or exposure to acidic environments, sulfites decompose, releasing sulfur dioxide (SO₂) gas and water. The acidification reaction proceeds as \ce{Na2SO3 + 2HCl -> 2NaCl + H2O + SO2}, shifting equilibria toward gaseous SO₂ and underscoring the ion's instability under protonation.^[18]^[19] In aqueous solution, the sulfite ion (SO₃²⁻) participates in pH-dependent acid-base equilibria, predominantly as SO₃²⁻ in basic media, bisulfite (HSO₃⁻) at neutral to mildly acidic pH (pKa ≈ 7.2 for HSO₃⁻ dissociation), and sulfurous acid (H₂SO₃) at lower pH (pKa ≈ 1.8). Hydrolysis of SO₃²⁻ generates hydroxide ions, yielding basic solutions: \ce{SO3^2- + H2O ⇌ HSO3^- + OH^-}.^[19]^[20] Sulfites function as reducing agents, undergoing oxidation to sulfate (SO₄²⁻) via reactions with molecular oxygen or stronger oxidants, as in the slow aerial oxidation: \ce{2SO3^2- + O2 -> 2SO4^2-}. This redox lability, driven by the nucleophilic sulfur center, renders sulfite solutions unstable in the presence of air or trace metals like copper, which catalyze oxidation.^[17] The ion's resonance-stabilized structure—featuring delocalized electrons across S-O bonds—imparts moderate thermal stability but heightened reactivity toward electrophiles and oxidants.^[20]

Production Methods

Industrial Synthesis

The primary industrial synthesis of sodium sulfite entails absorbing sulfur dioxide gas, generated by combusting elemental sulfur, into aqueous solutions of sodium hydroxide or sodium carbonate within countercurrent absorption towers.^[21]^[22] With sodium hydroxide, the reaction forms sodium sulfite directly via 2NaOH + SO₂ → Na₂SO₃ + H₂O, though it typically proceeds through a sodium bisulfite intermediate (NaHSO₃) at approximately 27 wt% SO₂ content.^[21]^[22] Using sodium carbonate introduces carbon dioxide as a byproduct, as in Na₂CO₃ + SO₂ → Na₂SO₃ + CO₂.^[22] The bisulfite intermediate, if formed, is converted to sulfite by adding sodium carbonate or hydroxide in a stirred vessel, followed by filtration to remove impurities and crystallization above 40°C to yield anhydrous sodium sulfite.^[21] Sodium metabisulfite (Na₂S₂O₅) is produced by further saturating sulfite or sodium hydroxide solutions with SO₂ to generate sodium bisulfite (NaHSO₃), which then undergoes dehydration or controlled acidification and cooling to precipitate the product, followed by rapid centrifugation or filtration and drying to prevent decomposition.^[21]^[23] This process leverages the equilibrium 2NaHSO₃ ⇌ Na₂S₂O₅ + H₂O, often in continuous packed column reactors for scalability.^[24] Commercial operations prioritize SO₂ recovery from flue gases or tail emissions where concentrations exceed 1.5%, enabling capacities up to 20,000 tons annually with stable product quality and minimal byproducts beyond CO₂ in carbonate-based routes.^[22] Purity standards for industrial-grade sodium sulfite typically reach or exceed 96-97%, achieved through purification steps that mitigate contaminants like excess sulfate or unreacted alkali.^[22]

Natural Occurrence

Sulfites, as the SO₃^2- ion or related species like bisulfite (HSO₃^-), occur naturally at trace levels primarily as reactive intermediates rather than stable compounds, owing to their rapid oxidation to sulfate (SO₄^2-) in oxygenated environments.^[25] In geological settings, sulfur dioxide (SO₂) from volcanic emissions dissolves in water to form sulfurous acid (H₂SO₃), which partially dissociates into bisulfite and sulfite; however, these persist only transiently before further oxidation, with concentrations typically below detectable thresholds in most deposits.^[26] Rare sulfite-bearing minerals, such as hannebachite (CaSO₃·0.5H₂O), form in fumarolic sublimates near active volcanoes, but they represent exceptional, low-abundance occurrences confined to specific high-temperature, low-oxygen niches.^[27] Biologically, sulfite arises endogenously in mammalian metabolism through the catabolism of sulfur-containing amino acids like cysteine. In this pathway, cysteine is oxidized to cysteinesulfinate, which decarboxylates and transaminates to sulfite, an obligate intermediate subsequently converted to sulfate by the enzyme sulfite oxidase to prevent toxicity; daily endogenous production in humans is estimated at 0.5–1.5 mg/kg body weight from cysteine breakdown alone.^[28] ^[29] Similar transient sulfite formation occurs in microbial sulfur metabolism across bacteria and archaea. In uneprocessed foods and beverages, natural sulfites derive from enzymatic or fermentative processes, with analytical surveys reporting levels generally under 10 mg/kg in fresh produce (e.g., onions, cabbage, apples) and naturally fermented items like unadulterated wine or sauerkraut, where yeast or bacterial activity reduces sulfate or oxidizes sulfides to SO₂ equivalents.^[30] ^[31] Within the broader sulfur cycle, sulfite functions as a key intermediate during microbial oxidation of sulfide or elemental sulfur to sulfate in anoxic sediments and aquatic systems, but its environmental half-life is short—often minutes to hours—due to abiotic and biotic oxidation, limiting accumulation.^[32] ^[25]

Practical Applications

Food and Beverage Preservation

Sulfites are widely employed in wine production as sulfur dioxide (SO₂) equivalents, typically added at concentrations of 20-100 mg/L free SO₂ to selectively inhibit spoilage organisms such as Acetobacter bacteria and wild yeasts, which can otherwise initiate acetic acid fermentation or off-flavors, while sparing desirable Saccharomyces strains tolerant up to 150-400 mg/L.^[33]^[34] These additions, often in forms designated as E220 (sulfur dioxide) or E221 (sodium sulfite) under European regulations, occur at crushing or post-fermentation stages to arrest microbial activity and limit oxidative damage without halting controlled alcoholic fermentation.^[35] In dried fruits and vegetables, sulfites such as sodium sulfite (E221) are applied at levels of 500-2000 mg/kg—commonly reaching 2000 mg/kg in apricots—to block enzymatic browning via polyphenol oxidase inhibition and suppress mold proliferation, preserving color, texture, and nutritional carotenoids during dehydration and storage.^[35]^[36] Similar applications extend to shrimp, where immersion in sodium metabisulfite solutions (e.g., 1.25% for 1 minute) prevents melanosis (black spot) by deactivating enzymes, and to beer brewing, where metabisulfites facilitate chloramine dechlorination at ratios of approximately 1.47 mg per mg chlorine while stabilizing against oxidation.^[37]^[38] Empirical trials indicate sulfite treatments substantially prolong shelf life by curtailing microbial spoilage; for instance, SO₂ levels exceeding 791 mg/kg in dried apricots effectively halted β-carotene oxidation and organism growth over storage periods, with overall spoilage reductions observed in controlled studies on preserved produce and beverages through inhibited enzymatic and microbial pathways.^[36]^[39]

Industrial and Other Uses

Sulfites, particularly in the form of bisulfite or sulfurous acid solutions, are employed in the sulfite pulping process to delignify wood chips for paper production by breaking down lignin through acidic hydrolysis and reduction.^[40] This method, patented in 1867, involves cooking wood in solutions of calcium, magnesium, sodium, or ammonium bisulfite at temperatures around 130–180°C, yielding pulps suitable for writing papers and tissues but producing weaker fibers compared to kraft processes.^[41] However, sulfite pulping has declined significantly since the 1960s, with no new mills constructed in the United States and its share reduced due to the dominance of more efficient kraft methods and environmental concerns over sulfur emissions.^[42] In boiler water treatment, sodium sulfite serves as an oxygen scavenger to mitigate corrosion by reacting with dissolved oxygen via the stoichiometry 2 Na₂SO₃ + O₂ → 2 Na₂SO₄, converting it to sulfate and preventing pitting on metal surfaces.^[43] This application is common in low-pressure systems below 1000 psi, where sodium sulfite is dosed into feedwater, often with catalysts to enhance reaction rates at lower temperatures.^[44] Catalyzed variants accelerate deoxygenation, ensuring residual oxygen levels below 0.005 ppm for effective protection.^[45] Sodium sulfite functions as a reducing agent in textile processing, aiding in vat dyeing by reducing dyes to their leuco forms for better solubility and fixation on fibers, as well as in dechlorination and bleaching steps.^[46] In photography, it acts as a preservative in developer solutions by scavenging dissolved oxygen, thereby stabilizing developing agents like metol against oxidation and maintaining solution efficacy during use.^[47] Sulfites, such as sodium metabisulfite, are utilized as antioxidants in pharmaceutical injectables to prevent oxidation of active ingredients, extending shelf life by inhibiting degradation in aqueous formulations.^[48] This role leverages their reducing properties to maintain drug potency in parenteral solutions.^[49]

Advantages of Sulfite Utilization

Antimicrobial and Antioxidant Mechanisms

Sulfites primarily manifest antimicrobial activity via the undissociated molecular sulfur dioxide (SO₂) species, which diffuses across microbial cell membranes into the cytoplasm, thereby acidifying the intracellular environment and inhibiting essential enzyme and protein functions critical for microbial metabolism and replication.^[50]^[51] This mechanism targets a broad spectrum of spoilage organisms, including bacteria such as Acetobacter species and lactic acid bacteria, as well as fungi, with efficacy dependent on maintaining sufficient free molecular SO₂ levels, typically requiring total sulfite concentrations exceeding 50 ppm in low-pH food matrices to achieve the active undissociated fraction above inhibitory thresholds (e.g., 0.5–1 ppm molecular SO₂).^[52]^[53] In parallel, sulfites serve as antioxidants through redox chemistry, wherein SO₂ acts as a reducing agent that scavenges reactive oxygen species and free radicals, while also reversibly inhibiting enzymes like polyphenol oxidase (PPO) to block the oxidation of phenolic substrates that lead to discoloration and quality degradation in fruits and vegetables.^[51] This enzymatic inhibition, combined with direct interception of carbonyl intermediates, further suppresses non-enzymatic Maillard reactions that contribute to off-flavors and nutrient loss during storage.^[54] Empirical measurements in preserved wines and juices demonstrate that sulfite supplementation can reduce oxidation rates by up to 50% compared to untreated controls, as evidenced by lowered levels of peroxides and preserved ascorbic acid content over time.^[55] These mechanisms exhibit synergy with endogenous food antioxidants, such as polyphenols, where sulfites enhance radical-scavenging capacity without displacing native protective systems, thereby extending shelf life while preserving the intrinsic compositional integrity of the product.^[56]^[57]

Economic and Safety Benefits in Preservation

Sulfites provide economic advantages in food preservation by extending shelf life and curtailing spoilage losses across supply chains. Their application inhibits enzymatic and nonenzymatic deterioration in fruits, vegetables, and beverages, addressing a substantial fraction of global food waste attributed to microbial and oxidative degradation.^[58] For example, treatment with sodium metabisulfite preserves key nutrients in fruit and vegetable byproducts, enabling their viable use and reducing discard volumes that would otherwise contribute to economic and environmental costs.^[59] Cost-effectiveness further bolsters sulfites' utility, as they require low dosages for efficacy, yielding favorable returns relative to pricier or less reliable alternatives like certain natural antimicrobials or irradiation processes. Sulfur dioxide-based agents are recognized for their affordability and broad-spectrum preservation, minimizing per-unit expenses while maintaining product quality over extended periods.^[60] Industry adoption reflects this, with sulfites integrated into processes for dried fruits, wines, and juices where they outperform costlier substitutes in scalability and performance.^[61] From a safety standpoint, sulfites enhance preservation reliability by suppressing microbial proliferation, thereby mitigating risks of pathogen contamination in susceptible products. Their antimicrobial action targets bacteria, yeasts, and molds, aligning with 20th-century advancements that correlated improved preservation with declines in foodborne outbreaks from spoiled goods.^[62]^[63] This contributes to net reductions in illness incidence by stabilizing low-moisture or fermented items against opportunistic pathogens, supporting safer distribution without reliance on more intensive interventions.^[64]

Biological Interactions

Human Metabolism of Sulfites

In healthy humans, sulfites are metabolized primarily through oxidation to sulfate by sulfite oxidase, a molybdenum cofactor-dependent enzyme localized to the mitochondrial intermembrane space.^[65]^[66] This enzymatic reaction represents the terminal step in the catabolic pathway for sulfur-containing amino acids, including cysteine and methionine, thereby preventing sulfite buildup, which is toxic at elevated levels.^[67] The process transfers electrons from sulfite to cytochrome c, integrating into the mitochondrial electron transport chain for ATP production. Endogenous sulfite generation predominates, deriving mainly from the oxidative metabolism of cysteine and methionine ingested via protein-rich foods, while exogenous sulfites from food and beverage additives contribute a minor fraction, typically 5-10% of total exposure under normal dietary conditions.^[68]^[69] Sulfite oxidase exhibits sufficient capacity to handle daily sulfite equivalents from dietary sulfur intake—approximately 1-2 g in adults—without detectable accumulation in plasma or tissues of individuals without genetic deficiencies.^[70] Clearance is rapid, with sulfite exhibiting a plasma half-life of about 10 minutes in healthy subjects, reflecting efficient enzymatic turnover and minimal systemic persistence.^[71] Secondary detoxification mechanisms, such as non-enzymatic conjugation with glutathione to form S-sulfoglutathione, provide backup pathways but play a limited role in routine metabolism compared to sulfite oxidase.^[72] Genetic polymorphisms impairing sulfite oxidase function are exceedingly rare in the general population, ensuring robust handling of sulfite loads in the absence of isolated deficiencies or molybdenum cofactor disruptions.^[73]

Evidence on Sensitivity Prevalence

Controlled challenge studies indicate that sulfite sensitivity affects approximately 3% to 5% of asthmatic individuals, with a landmark double-blind, placebo-controlled trial published in 1986 reporting a prevalence of 3.9% among 200 adult asthmatics subjected to oral sulfite challenges.^[74] This figure aligns with broader reviews estimating rates between 3% and 10% in asthmatics, though higher incidences—up to 20%—have been observed in steroid-dependent pediatric asthmatics.^[75]^[76] In the general population, prevalence is substantially lower, estimated at less than 1%, with sensitivity predominantly confined to subsets of poorly controlled or steroid-reliant asthmatics rather than the broader populace.^[77]^[78] Accurate diagnosis necessitates double-blind, placebo-controlled provocation tests, as self-reported sensitivities significantly overestimate true reactivity due to nocebo effects and nonspecific symptoms; for instance, only 4 of 24 self-identified wine-sensitive asthmatics confirmed sulfite responsiveness in single-dose challenges.^[79] Such discrepancies highlight that anecdotal reports can inflate perceived prevalence by factors of 5 to 10 times compared to empirical verification.^[80] Recent analyses, including data supporting the American Contact Dermatitis Society's 2024 designation of sulfites as Allergen of the Year, emphasize contact dermatitis risks in patch-tested cohorts, where sulfite relevance exceeds 50% among positives, but underscore rarity of systemic ingestion-related reactions outside high-risk asthma subgroups.^[81]^[82] These findings reaffirm low overall rates, prioritizing controlled metrics over unverified claims.

Adverse Reactions and Controversies

Reported Symptoms and Affected Populations

Reported symptoms of sulfite sensitivity primarily manifest as respiratory issues in susceptible individuals, including bronchoconstriction leading to wheezing, shortness of breath, and coughing, alongside urticaria (hives) and gastrointestinal disturbances such as nausea, vomiting, diarrhea, and abdominal cramps.^[83]^[6]^[84] These reactions are most commonly verified through controlled oral challenges in asthmatic patients exhibiting sensitivity, where symptoms onset rapidly following exposure to sulfite-containing foods or beverages.^[76] Topical exposure to metabisulfites, often found in cosmetics, pharmaceuticals, and antihemorrhoidal creams, has been associated with verified cases of allergic contact dermatitis, including eczematous reactions on the lips (cheilitis) and facial eczema.^[85]^[6] Patch testing confirms relevance in a majority of such cases, with sodium metabisulfite identified as the primary allergen in occupational and consumer product exposures.^[86] Affected populations are predominantly those with severe or steroid-dependent asthma, who demonstrate heightened reactivity to sulfur dioxide (SO2) released from sulfites, as well as individuals with atopic conditions predisposing to urticaria or dermatitis.^[6]^[76] Anaphylaxis remains rare and is typically documented only in oral challenges exceeding 100 mg of sulfite equivalents, distinguishing it from more common non-IgE-mediated responses.^[68] Dose-response patterns indicate that most sensitive asthmatics tolerate exposures below 20-50 mg SO2 equivalents, with thresholds varying by individual; natural sulfite levels in wines (typically 10-50 mg/L total SO2) seldom provoke symptoms compared to higher concentrations in processed foods or added forms in dried fruits and juices.^[68]^[78]^[87]

Empirical Studies and Debunking Overstatements

Empirical challenges conducted since the 1970s, including double-blind placebo-controlled trials, have consistently demonstrated that sulfite-induced adverse reactions occur predominantly in a small subset of individuals with pre-existing sensitivity, such as certain asthmatics, with no established causal association to chronic diseases like cancer or cardiovascular conditions in the tolerant population.^[88]^[89] Longitudinal cohort studies and toxicological reviews through the 2020s similarly fail to identify sulfites as a driver of long-term pathology outside acute hypersensitivity events, attributing reported correlations in additive-laden diets to confounding factors like overall processing or co-exposures rather than sulfite-specific mechanisms.^[6] Recent investigations into food additives' effects on gut and lung health (2023–2025) have highlighted associative patterns, such as microbiome shifts or inflammatory markers in high-additive consumers, but these lack sulfite isolation and causal inference, often conflating sulfites with broader preservative classes or dietary patterns without controlled sulfite dosing.^[4] Metabolic overload from sulfites, which could theoretically strain sulfite oxidase pathways, demands intakes exceeding the acceptable daily intake (ADI) of 0.7 mg SO₂ equivalents/kg body weight—a threshold rarely approached in typical diets and unsupported by population-level enzyme deficiency data beyond genetic rarities.^[90] Claims of widespread sulfite intolerance amplified in media overlook that over 99% of the general population exhibits tolerance, with sensitivity confined to approximately 1% overall and 3–10% of asthmatics, per challenge-confirmed prevalence.^[91]^[88] This hype disregards sulfites' role in curbing food waste through effective microbial inhibition, potentially increasing spoilage-related risks if curtailed. Alternatives like benzoates carry elevated toxicity profiles per milligram, including benzene formation—a known carcinogen—under certain conditions, underscoring sulfites' relative safety margin for the majority.^[92]^[93]

Regulatory Oversight

Usage Limits and Labeling Mandates

The acceptable daily intake (ADI) for sulfites, expressed as sulfur dioxide equivalents, is established at 0–0.7 mg per kg body weight by the Joint FAO/WHO Expert Committee on Food Additives (JECFA) and confirmed as a temporary value by the European Food Safety Authority (EFSA) based on toxicological data including no-observed-adverse-effect levels from animal studies.^[94]^[35] Maximum permitted levels are set to maintain exposure below this ADI; for example, the European Union limits sulfites to 200 mg/L in white and rosé wines, while dried fruits such as apricots may contain up to 2000 mg/kg.^[95] In the United States, the Food and Drug Administration (FDA) caps sulfites at 350 mg/L in wine.^[96] Following reports of adverse reactions linked to high exposures, the FDA banned sulfite use on fresh fruits and vegetables, including salad bar produce, effective in 1986 to eliminate risks from direct application on ready-to-eat items.^[97] Labeling mandates require declaration of sulfites exceeding 10 mg/kg or 10 ppm in finished products to inform consumers, with the U.S. implementing this threshold via FDA regulations effective January 1987 for foods containing 10 ppm or more total SO₂.^[98] In the European Union, similar requirements under food additive regulations mandate "contains sulfites" for levels above 10 mg/kg or per liter, often using E-number codes such as E220 for sulfur dioxide and E221–E228 for various sulfite salts to denote specific forms.^[99] These thresholds apply regardless of whether sulfites are added or naturally occurring, ensuring transparency for potential sensitivities.^[98] Regulatory enforcement involves routine monitoring and import controls, with the FDA issuing import alerts for products violating sulfite limits, such as those exceeding thresholds in fresh or preserved foods from non-compliant sources.^[100] Compliance is generally high in domestic production due to established good manufacturing practices, though violations are more frequently associated with imported goods like dried fruits or seafood where undeclared or excessive sulfites have been detected during border inspections.^[101]

Global Differences and Compliance

In the United States, the Food and Drug Administration (FDA) mandates labeling for sulfites in foods when total sulfur dioxide exceeds 10 parts per million (ppm), with a voluntary "contains sulfites" declaration applicable above this threshold; for wines, the Alcohol and Tobacco Tax and Trade Bureau (TTB) enforces a similar requirement for levels at or above 10 ppm.^[98]^[102] In contrast, the European Union requires mandatory declaration of sulphur dioxide and sulphites in prepacked foods when concentrations surpass 10 mg/kg or 10 mg/L, expressed as total SO2 equivalents, under Regulation (EU) No 1169/2011.^[103]^[104] These frameworks reflect differing emphases: the U.S. approach aligns with risk-based thresholds derived from detection limits and sensitivity data, while the EU incorporates precautionary elements through uniform allergen-style disclosure. Global harmonization efforts, led by the Codex Alimentarius Commission, establish maximum permitted levels for sulfites in the General Standard for Food Additives (GSFA, Codex Stan 192-1995), with labeling guidance prioritizing declaration above 10 ppm to protect sensitive individuals, influencing national standards in over 180 countries.^[105]^[30] Regional variations persist; for instance, exporting nations in Asia and Africa often maintain higher domestic tolerances for sulfites in dried fruits and seafood to support production, but must adhere to stricter importer limits—such as U.S. FDA import alerts for undeclared residues exceeding 10 ppm—leading to adjusted practices for international markets.^[100]^[30] The European Food Safety Authority's (EFSA) 2022 re-evaluation of sulfites (E 220–228) identified potential safety concerns for high consumers, with margin of exposure (MOE) values below 80 indicating exceedance risks relative to the temporary acceptable daily intake (ADI) of 0.7 mg SO2 equivalents/kg body weight, though insufficient new toxicological data precluded revised maximum levels.^[4] Compliance across borders is complicated by analytical methods; the modified Monier-Williams distillation, involving acid liberation of SO2 followed by titration, serves as the reference for total sulfite quantification but can yield variability in complex matrices like dried fruits, prompting disputes in trade verifications.^[106] International trade frictions arise from residue inconsistencies, as evidenced by EU Rapid Alert System for Food and Feed (RASFF) notifications and U.S. detentions of shipments with undeclared sulfites, underscoring the need for standardized testing to resolve exporter-importer divergences.^[107]^[108]

Associated Metabolic Conditions

Sulfite Oxidase Deficiency

Sulfite oxidase deficiency, also known as isolated sulfite oxidase deficiency (ISOD), is an autosomal recessive neurometabolic disorder caused by biallelic pathogenic variants in the SUOX gene, which encodes the mitochondrial enzyme sulfite oxidase.^[109]^[110] This enzyme catalyzes the terminal step in the metabolism of sulfur-containing amino acids, oxidizing sulfite (produced from cysteine and methionine catabolism) to sulfate for safe excretion.^[109] Mutations impair this conversion, leading to toxic accumulation of sulfite and its conjugate S-sulfocysteine in tissues, particularly the brain, causing neuronal damage through oxidative stress and excitotoxicity.^[111]^[112] The classic early-onset form manifests neonatally with intractable seizures, poor feeding, hypotonia progressing to spasticity, and developmental arrest, often accompanied by ectopia lentis (lens dislocation) by early childhood.^[109]^[110] A rarer late-onset variant emerges between 6 and 18 months, typically triggered by febrile illness, presenting with milder seizures, ataxia, and gradual intellectual disability but still featuring elevated urinary sulfites and S-sulfocysteine as hallmarks.^[110]^[113] Diagnosis relies on detecting these metabolites in urine, alongside absent enzyme activity in fibroblasts and genetic confirmation of SUOX variants; it must be differentiated from molybdenum cofactor deficiency, which phenocopies ISOD but involves broader enzyme deficits and purine abnormalities.^[109]^[114] ISOD has an estimated incidence of approximately 1 in 1.4 million births, with fewer than 50 cases documented worldwide, though underdiagnosis is likely due to nonspecific early symptoms mimicking hypoxic-ischemic encephalopathy.^[112]^[109] No curative therapy exists; management is symptomatic, including anticonvulsants for seizures and supportive care for feeding and tone issues, with experimental low-sulfur diets (restricting methionine and cysteine) offering limited mitigation of metabolite buildup but no reversal of neurodegeneration.^[109] Prognosis is dismal, with early-onset cases often fatal in infancy and survivors exhibiting profound disability.^[110] In affected individuals, exogenous sulfites from diet or additives exacerbate endogenous toxicity due to the enzymatic block, amplifying neurological insult.^[109] However, as a monogenic disorder impacting far less than 0.0001% of the population, ISOD does not substantiate regulatory restrictions on sulfite preservatives for the general populace, where functional sulfite oxidase ensures negligible risk from typical exposures.^[112] This contrasts sharply with purported common sensitivities, which lack comparable biochemical deficits and are not genetically mediated.^[114]

References

[1]
Sulfite | O3S-2 | CID 1099 - PubChem
Sulfite is a sulfur oxoanion that is the conjugate base of hydrogen sulfite (H2SO3). It is a sulfur oxoanion, a sulfur oxide and a divalent inorganic anion.
[2]
[PDF] Chapter 2: Molecular Structure and Bonding 11
The Lewis structure of sulfite ion is shown below. With three cr bonds and one lone pair, you should expect a trigonal-pyramidal geometry such as NH3.
[3]
https://chem.libretexts.org/Bookshelves/Analytical_Chemistry/Supplemental_Modules_(Analytical_Chemistry)/Qualitative_Analysis/Properties_of_Select_Nonmetal_Ions/Sulfite_Ion_(SO%E2%82%83%C2%B2%E2%81%BB)
[4]
Sulfites: safety concern for high consumers, but data lacking - EFSA
Nov 24, 2022 · Sulfites are added as preservatives and antioxidants (for example, to prevent browning) to a range of foodstuffs including dried fruit and ...
[5]
Food safety risk assessment for estimating dietary intake of sulfites ...
They are used in the food industry to maintain food color, to prolong shelf life, and to prevent microbial growth [11], [19], [37], [34]. Sulfites are also ...
[6]
Adverse reactions to the sulphite additives - PMC - NIH
Exposure to sulphites has been reported to induce a range of adverse clinical effects in sensitive individuals, ranging from dermatitis, urticaria, flushing, ...
[7]
Clinical effects of sulphite additives - PubMed
Sulphites are widely used as preservative and antioxidant additives in the food and pharmaceutical industries. Topical, oral or parenteral exposure to ...
[8]
Safety risks associated with sulfite-containing compounded drugs
Jun 5, 2024 · Sulfites may cause allergic-type reactions including anaphylactic symptoms and life-threatening or less severe asthmatic episodes in susceptible ...
[9]
Sulfite
- **Structure Info for Sulfite Ion (O3S-2, CID 1099):**
[10]
Sulfite - an overview | ScienceDirect Topics
The sulfite anion ( SO 3 2 − ) is a reactive and therefore toxic sulfur compound that can cause damage to proteins, nucleic acids, and lipids of living ...
[11]
SO32- lewis structure, molecular geometry, hybridization, and bond ...
Oct 11, 2023 · In the sulfite [SO3]2- ion, there are 2 single bonds, 1 double bond and 1 lone pair on the central sulfur atom which makes a total of 4 electron ...Missing: ray crystallography<|separator|>
[12]
mp-21282: Na2SO3 (Trigonal, P-3, 147) - Materials Project
Na₂SO₃ crystallizes in the trigonal P̅3 space group. There are three inequivalent Na¹⁺ sites. In the first Na¹⁺ site, Na¹⁺ is bonded in a 6-coordinate ...
[13]
Disulfite | O5S2-2 | CID 159940 - PubChem - NIH
Disulfite | O5S2-2 | CID 159940 - structure, chemical names, physical and chemical properties, classification, patents, literature, biological activities, ...
[14]
Equilibrium quotient for the isomerization of bisulfite ion from HSO3
Kinetics of oxygen exchange between the two isomers of bisulfite ion, disulfite ion (S2O52-), and water as studied by oxygen-17 nuclear magnetic resonance ...
[15]
Sodium Sulfite - BYJU'S
Physical Properties of Sodium Sulfite · The molar mass of this compound is 126.043 grams per mole. · Anhydrous sodium sulfite exists as a white, odourless solid ...
[16]
SODIUM SULFITE - CAMEO Chemicals - NOAA
White odorless powder. Density 2.633 g / cm3. Moderately toxic. Sinks in water and dissolves slowly. Also transported as a heptahydrate Na2SO3.7H2O.<|separator|>
[17]
Sulfite - an overview | ScienceDirect Topics
Sodium sulfite (SS) is a white, odorless, crystalline powder with sulfurous taste, that has reducing properties. The compound is soluble in water (30.7/100, g/g ...
[18]
Sodium Sulfite: Structure, Properties, Uses in Chemistry - Vedantu
Rating 4.2 (373,000) Sodium sulfite is defined as a white, crystalline, water-soluble solid with a sulfurous and salty taste. When heated, it decomposes.<|separator|>
[19]
Sulfite Ion (SO₃²⁻) - Chemistry LibreTexts
Aug 29, 2023 · Sulfite ion is a weak base, but does undergo some hydrolysis to produce basic solutions. In acidic solution, the equilibria are shifted to form sulfurous acid.
[20]
Sulfite Ion Formula - SoftSchools
The sulphite ion chemical formula is SO 3 2- . The molar mass is 80.06 g/mol. It is formed by one centered sulfur cation S 4+ and three oxygen anions O 2-.Missing: definition | Show results with:definition
[21]
Sulfur Dioxide and Some Sulfites, Bisulfites and Metabisulfites - NCBI
In a typical sodium sulfite manufacturing process, a solution of sodium carbonate is allowed to percolate downwards through a series of absorption towers ...
[22]
Production process of sodium sulfite-Industry News-Changsha ...
Aug 11, 2022 · The traditional production process of sodium sulfite is to produce SO₂ from monomeric sulfur, and then react with soda ash (Na2CO3) and ...
[23]
Production of pure sodium metabisulfite and sodium sulfite
In the first stage, a maximum of about 50% by weight aqueous caustic soda solution is reacted with sulfur dioxide up to a pH of 3.8 to 4.5 and the deposited ...
[24]
Cocurrent flow process for the manufacture of sodium sulfite and ...
Sodium (bi)sulfites are produced by the steps of: (a) introducing a stream of aqueous sodium carbonate into the top end of a main packed column reactor; ...Missing: industrial | Show results with:industrial
[25]
The life sulfuric: microbial ecology of sulfur cycling in marine ...
Cycling between the most oxidised (+6, sulfate) and most reduced (–2, sulfide) states of sulfur involves several inorganic sulfur compounds of intermediate ...
[26]
Origin of secondary sulfate minerals on active andesitic ...
Sulfate-bearing hydrothermal alteration in active stratovolcanoes occurs episodically when sulfur-rich volcanic gases are introduced into meteoric water, with ...
[27]
[PDF] Origin of secondary sulfate minerals on active andesitic ...
Sulfate minerals in altered rocks on the upper flanks and summits of active andesitic stratovolcanoes result from multiple processes. The origin of these ...
[28]
Homeostatic impact of sulfite and hydrogen sulfide on cysteine ...
Aug 8, 2018 · Sulfite is a common intermediate in both catabolic pathways. Sulfite is considered as cytotoxic and produces neurotoxic S-sulfonates. As a ...
[29]
Metabolism of Sulfur-Containing Amino Acids: How the Body Copes ...
Although the majority of sulfite is produced endogenously from Met/Cys catabolism, sulfite is also consumed in the diet as a natural component of foods, as a ...
[30]
Sulfites - International | Food Allergy Research & Resource Program
Sulfites may also occur naturally in some foods especially fermented foods ... However, naturally occurring levels of sulfite are typically quite low (<10 ...Missing: products | Show results with:products
[31]
Sulfites | Natural Grocers
Sulfites naturally occur in some foods, such as fermented foods (sauerkraut, kimchi, etc.), wine and wine vinegars, and even some vegetables, but generally ...
[32]
The Biogeochemical Sulfur Cycle of Marine Sediments - Frontiers
Most of the sulfide is ultimately reoxidized back to sulfate, via diverse sulfur intermediates, by geochemical or microbial reactions that involve oxygen, ...
[33]
[PDF] ALTERNATIVE METHODS OF SULFUR DIOXIDE USED IN WINE ...
Especially yeasts are very sensitive to SO2. Bacteria become inactive in the amount of 40-50 mg/L SO2, while wine yeasts are resistant to 150-400 mg/L of. SO2.
[34]
https://pulsar-foods.com/blogs/news/sulfites-publish-version-2
[35]
Re-evaluation of sulfur dioxide–sulfites (E 220–228) - EFSA
Apr 14, 2016 · Scientific Opinion on the re-evaluation of sulfur dioxide (E 220), sodium sulfite (E 221), sodium bisulfite (E 222), sodium metabisulfite (E 223) ...
[36]
[PDF] CHEMICAL and MICROBIAL DIFFERENCES in DRIED APRICOTS ...
Both color criteria closely depend upon the SO2 concentration which should be over 791 mg SO2/kg to prevent the formation of brown color and the oxidation of β- ...
[37]
US5830522A - Method for preserving seafood - Google Patents
The usual application is by immersing the shrimp in a dilute (1.25% by weight) sodium metabisulfite solution for one minute. This treatment retards the spoilage ...
[38]
Sodium metabisulfite to clear chloramine - Brew Your Own
The dechlorination reaction requires 1.47 mg of sodium metabisulfite to reduce 1 mg of free chlorine. In practice, this ratio is increased two–three fold. In ...
[39]
Sulphur dioxide evolution during dried apricot storage - ScienceDirect
Sulphur dioxide is used as a pre-treatment to facilitate drying, improve product quality and extend the shelf life of apricots. During storage, SO2 losses ...
[40]
Pulping - an overview | ScienceDirect Topics
Sulfite pulping is an acidic process that produces lower yields than the kraft process, and the fibers are also weaker. Its advantage is that a greater ...
[41]
Sulfite process - CAMEO
Oct 2, 2024 · A chemical method of producing paper pulp from wood using high heat and Sulfur dioxide. The sulfite process was first patented in 1867.
[42]
[PDF] Energy and Environmental Profile of the U.S. Pulp and Paper Industry
pulping, sulfite pulping is on the decline. No new sulfite mills have been built in the U.S. since the 1960s (Smook 1992). Table 4-4 shows the geographical.
[43]
[PDF] Sulfites for Oxygen Control - Scranton Associates
Sulfites react with oxygen, forming sodium sulfate, and are used to control oxygen in steam systems, especially in lower pressure installations.Missing: deoxygenation | Show results with:deoxygenation
[44]
[PDF] BOILER DISSOLVED OXYGEN CONTROL
SODIUM SULFITE: This product is used extensively on low-pressure boilers, below 6900 kpa (1000 psi). Although reasonably priced and easy to handle, it.
[45]
Sulfite & Catalyzed Sulfite in Steam Boilers | Chardon Labs
Jul 27, 2022 · Sulfite removes oxygen from water, preventing corrosion. Catalyzed sulfite accelerates this reaction, reacting rapidly at all temperatures.Missing: deoxygenation | Show results with:deoxygenation<|separator|>
[46]
Sulfite - BASF
Textiles produced using BASF sulfites as reducing agents are now proven to be responsibly manufactured.
[47]
the Effect of Sulfite in Developer Solutions
Sodium sulfite is the one chemical customarily found in all formulae for organic photographic developing agents. Its use as a protective against aerial ...
[48]
Sulfite - an overview | ScienceDirect Topics
Sulfites are commonly used to extend the shelf life of many injectable drugs ... They are also used as antioxidants and preservatives in many pharmaceuticals.
[49]
Sodium Sulfite: An All-Purpose Chemical with Numerous Applications
Apr 18, 2023 · In the pharmaceutical industry, it's used as an anti-oxidant preservative for drugs such as injectable solutions, oral liquids or suspensions ...
[50]
[PDF] Sulfur Dioxide: Science behind this anti-microbial, anti-oxidant, wine ...
The mechanism for sulfur dioxide's antimicrobial affect works by the sulfur dioxide entering the microbe and disrupting the activity of the enzymes and proteins ...
[51]
Sulfur Dioxide and Sulfites - ResearchGate
Antimicrobial efficacy is mainly based on the molecular form that freely diffuses through cell membranes and decreases intracellular pH. Sulphites are also ...
[52]
[PDF] Sulfur Dioxide - Agricultural Marketing Service - USDA
Oct 13, 2011 · ... sulfur dioxide. 359 concentrations of less than 100 ppm. Concentrations of sulfur dioxide between 50 and 100 ppm are allowed. 360 for grape ...Missing: undissociated | Show results with:undissociated
[53]
juice stabilization and preservation
Fortunately, by excluding oxygen and maintaining low but significant SO2 levels (~50 ppm), incipient spoilage is easily avoided. In fact, the vinegar ...
[54]
Control of Maillard Reactions in Foods: Strategies and Chemical ...
May 23, 2017 · Scavenging of Maillard-Derived Radicals by Polyphenols. Maillard reactions also generate stable radicals, which has been characterized in ...
[55]
(PDF) Effect of sulfites on the in vitro antioxidant activity of wines
The objective of this study was to assess the contribution of SO2 to the overall antioxidant activity of wines.
[56]
View of Effect of sulfites on the in vitro antioxidant activity of wines
Depending on the assay, sO2showed both synergistic and antagonistic effects with the antioxidants naturally present in wines. 506Ital. J. Food Sci., vol. 27 ...
[57]
Effect of Sulfites on Antioxidant Activity, Total Polyphenols, and ... - NIH
Mar 9, 2018 · The addition of sulfites to organic white wines (at 25–200 mg/L wine) clearly resulted in a significant overestimation of antioxidant activity ...
[58]
Short Review of Sulphites as Food Additives - ResearchGate
Aug 6, 2025 · Sulfite is used as a preservative in a variety of food and pharmaceutical industries to inhibit enzymatic and nonenzymatic browning and in ...
[59]
Preservation of fruit and vegetable discards with sodium metabisulfite
Oct 15, 2018 · Sodium metabisulfite was used for the preservation of fruit and vegetable discard. · Metabisulfite effectively preserved nutrient components in ...
[60]
Study finds safer alternative for sulphur preservative - WUN
Sep 2, 2011 · The reality is that sulphur is incredibly cheap and effective so what we're now looking at simply finding ways to better use it.”
[61]
The uses of sulphur dioxide in the food industry: A review
Aug 6, 2025 · Data suggest that treating foods with 50 to 500 ppm SO2 probably would not effectively degrade appreciable amounts of aflatoxin. Treating foods ...
[62]
Achievements in Public Health, 1900-1999: Safer and Healthier Foods
During the early 20th century, contaminated food, milk, and water caused many foodborne infections, including typhoid fever, tuberculosis, botulism, ...
[63]
What Do We Know About Sulfites and Food Preservation?
Sulfites also kill bacteria and fungus, giving foods a longer shelf life. And they slow the natural breakdown of vitamin C and A, lending to the claim that ...<|separator|>
[64]
An Evaluation of Alternatives to Nitrites and Sulfites to Inhibit ... - NIH
Oct 31, 2016 · This study evaluated the capacity of sodium nitrite, sodium sulfite, a sodium acetate product (TQI C-6000), and chitosan to inhibit two important foodborne ...
[65]
Sulfite oxidase, mitochondrial - Homo sapiens (Human) | UniProtKB
Catalyzes the oxidation of sulfite to sulfate, the terminal reaction in the oxidative degradation of sulfur-containing amino acids.
[66]
Sulfite oxidizing enzymes - PMC - PubMed Central
Sulfite oxidizing enzymes are essential mononuclear molybdenum (Mo) proteins involved in sulfur metabolism of animals, plants and bacteria.
[67]
Molecular Basis of Sulfite Oxidase Deficiency from the Structure of ...
The molybdenum-containing enzyme sulfite oxidase catalyzes the conversion of sulfite to sulfate, the terminal step in the oxidative degradation of cysteine ...
[68]
Sulfite oxidase - Wikipedia
It oxidizes sulfite to sulfate and, via cytochrome c, transfers the electrons produced to the electron transport chain, allowing generation of ATP in oxidative ...
[69]
[PDF] Sensitivity to Ingested Sulfites - UNL Digital Commons
Endogenous sulfite arises from the metabolism of the sulfur-containing amino acids, cysteine and methionine. In most cases, an extra exogenous load of ingested ...
[70]
[PDF] Sulfites: Human health tier II assessment
Jun 28, 2013 · Sulfites generated in the human body (endogenous sulfites) can be oxidised by a mitochondrial enzyme sulfite oxidase, to sulfates that are ...
[71]
Are we getting enough sulfur in our diet? - Nutrition & Metabolism
Nov 6, 2007 · The RDA for methionine (combined with cysteine) for adults has been set at 14 mg/Kg of body weight per day. Therefore a person weighing 70 Kg, ...
[72]
Failure of sulfites to produce clinical responses in patients with ...
Assuming in- gested sulfites equilibrate throughout extracellular body fluids (estimated to be 25% of body weight) and the half- life of sulfites is IO minutes, ...Missing: humans | Show results with:humans
[73]
A possible involvement of glutathione in the detoxication of sulfite
Glutathione (gsh) has been proposed to play a role in detoxification of SO2 through the sulfitolysis of glutathione disulphide (gssg) to S-sulphoglutathione ...
[74]
Level of Sulfite Oxidase Activity Affects Sulfur and Carbon ... - NIH
Jun 24, 2021 · Genetic deficiency of human sulfite oxidase leads to severe neurological abnormalities that often result in death in infancy (Johnson and Wadman ...
[75]
Prevalence of sensitivity to sulfiting agents in asthmatic patients
On the basis of this challenge study, the best estimate of the prevalence of sulfite sensitivity in the asthmatic patients studied is 3.9 percent. This ...
[76]
Sulphites in food & drinks in asthmatic adults & children:... - LWW
The actual prevalence of sulfite sensitivity in individuals with asthma is not known; however, the reported prevalence varies from 3% to 10%.[2 ,5 ,10] ...
[77]
Sulfite Sensitivity - The Asthma & Allergy Center
Generally, sulfite sensitivity is found in people with asthma who are steroid dependent. In steroid-dependent children, the prevalence has been found to be 20%.
[78]
https://farrp.unl.edu/farrp-resources/general-information-food-allergies-sensitivities/idiosyncratic-illnesses/
[79]
Idiosyncratic illnesses | Food Allergy Research & Resource Program
Even among severe asthmatics, the prevalence of sulfite sensitivity is only about 5%. By extrapolating from the challenge study results and knowing the ...
[80]
Role of sulfite additives in wine induced asthma: single dose ... - NIH
RESULTS—Four of the 24 self-reporting wine sensitive asthmatic patients were found to respond to sulfite additives in wine when challenged in a single dose ...
[81]
Sulfite allergy evaluation
Apr 5, 2022 · The diagnosis of sulfite sensitivity can be confirmed by a "challenge" in which sulfite is administered in solutions or capsules of increasing concentration.<|separator|>
[82]
Sulfites: Allergen of the Year 2024 - PubMed
Aug 17, 2023 · The American Contact Dermatitis Society chose sulfites as the Allergen of the Year for 2024 to raise awareness about this significant allergen.
[83]
https://my.clevelandclinic.org/health/diseases/11323-sulfite-sensitivity
[84]
Sulfite Allergy & Sensitivity: Symptoms, Tests & Treatments
Sulfites can trigger asthma attacks and allergic reactions, including wheezing, coughing and skin reactions ... Sulfites are chemicals used as preservatives.
[85]
Sulfite Allergy - News-Medical
Sulfites can trigger allergic reactions in some people, mainly those having asthma. ... Digestive symptoms - diarrhea, stomach cramps, vomiting, and nausea ...
[86]
Sulfites: Allergen of the Year 2024 | Dermatitis®
Aug 20, 2023 · Eczematous dermatitis of the lips is common in ... Allergic contact dermatitis from sodium metabisulfite in an antihemorrhoidal cream.
[87]
Allergic contact dermatitis caused by sodium metabisulfite - PubMed
Conclusions: Allergic contact dermatitis caused by sulfites is frequent and often relevant. One should be aware of possible relevant sources of exposure, ...Missing: lip | Show results with:lip
[88]
The Bottom Line on Sulfites in Wine - Wine Folly
A well made dry red wine typically has about 50 mg/l sulfites. Wines with lower acidity need more sulfites than higher acidity wines. At pH 3.6 and above, wines ...Are Sulfites In Wine Bad? · Stacking Up Sulfites In Wine · Why Are Sulfites In Wine?Missing: triggering | Show results with:triggering
[89]
Sulfite hypersensitivity. A critical review - PubMed - NIH
Although there is some disagreement on its prevalence, a number of studies have indicated that 5 to 10% of all chronic asthmatics are sulfite hypersensitive.Missing: overstatements debunked
[90]
FCS8787/FY731: Sulfites: Separating Fact from Fiction - Ask IFAS
Residual levels do not usually exceed several hundred parts per million (ppm) but may approach 1,000 ppm in certain fruit and vegetable products (Sapers 1993; ...
[91]
Follow‐up of the re‐evaluation of sulfur dioxide (E 220), sodium ...
Sulfur dioxide–sulfites (E 220–228) were re‐evaluated in 2016, resulting in the setting of a temporary ADI of 0.7 mg SO 2 equivalents/kg bw per day.
[92]
Sulfa, Sulfite & Sulfate: Allergy Risk or No Concern?
Aug 7, 2019 · Sulfites cause allergy in approximately 1% of population. Hypersensitivity reactions include hives, dyspnea, and in severe cases, anaphylactic shock.Missing: overstatements | Show results with:overstatements
[93]
Understanding Food Preservatives: What Are The Health Risks?
Nov 16, 2021 · Though both help limit microbial growth, benzoate contains small amounts of the carcinogen benzene. Sulfites: Used to prevent browning, ...Missing: alternatives | Show results with:alternatives
[94]
Top 8 Common Food Preservatives To Avoid - Perfect Keto
Food preservatives like nitrites, sodium benzoate, BHA, BHT, and sorbate may prevent food spoilage, but these food additives have their downside.
[95]
sulfur dioxide - WHO | JECFA
Sulfur dioxide is a food additive used as an antioxidant, flour treatment agent, and preservative. Its ADI is 0-0.7 mg/kg bw.Missing: EFSA | Show results with:EFSA
[96]
Sulphites in Wine: The In-Depth Guide - Vinerra
Jan 5, 2024 · White wine typically has a higher sulphite concentration due to the lack of the natural preservatives found in red wines, such as tannins and ...Missing: triggering | Show results with:triggering
[97]
What Are Sulfites in Wine? Everything You Need to Know - Coravin
Oct 28, 2024 · Dried Fruits: Can contain up to 2000 mg/L of sulfites ... In the United States, the maximum allowable sulfite concentration is 350 mg/L.Missing: permitted | Show results with:permitted
[98]
FDA Bans Use of Sulfites on Some Foods - Los Angeles Times
Jul 10, 1986 · The FDA had proposed the ban last August after conducting a study prompted by reports of 13 deaths and at least 500 allergic reactions ...
[99]
Sulfites - USA | Food Allergy Research & Resource Program - FARRP
Sulfur dioxide (SO2), sodium bisulfite (NaHSO3), potassium metabisulfite ... A detectable amount of sulfiting agent is 10 parts per million or more of the sulfite ...
[100]
More data on sulfites needed to “fully confirm” safety - EFSA
Apr 14, 2016 · The current combined safe level for seven sulfites used as additives in wine and other foods is sufficiently protective for consumers.
[101]
Import Alert 99-21 - accessdata.fda.gov
If these foods are found to contain sulfiting agent(s) at 10 ppm or greater, Divisions should consult with CFSAN, Office of Compliance, Division of Enforcement ...Missing: monitoring | Show results with:monitoring
[102]
[PDF] Imports From China and Food Safety Issues - AgEcon Search
The study also describes recent developments in food safety monitoring and enforcement for ... sulfite levels, accounted for 22 percent of 2007-08 violations.
[103]
Wine Labeling: Declaration of Sulfites | TTB
Sep 26, 2019 · The statement is required where sulfur dioxide or a sulfiting agent is detected at a level of 10 or more parts per million (ppm), measured as ...
[104]
Food allergen labelling and information requirements technical ...
Aug 23, 2023 · The rules require sulphur dioxide and/or sulphites to be labelled when present above 10 mg/Kg or 10 mg/litre (calculated in terms of the total ...
[105]
Sulphur Dioxide and Sulphites - Food Safety Authority of Ireland
Therefore, for prepacked foods, their presence in a food or beverage must be indicated on the label, by its full name, where the level exceeds 10 mg/kg or 10 mg ...<|separator|>
[106]
[PDF] General Standard for Food Additives Codex Stan 192-1995
This Standard sets forth the conditions under which food additives may be used in all foods, whether or not they have previously been standardized by Codex. The ...
[107]
Reevaluation of Monier-Williams method for determining sulfite in food
We found that the Monier-Williams distillation yielded greater than 90% recovery of sulfite added to foods such as table grapes, hominy, dried mangoes, and ...
[108]
Border Rejections Reported in the Rapid Alert System for Food and ...
The purpose of this study was to analyse border rejections reported in the RASFF in 2008–2023, considering hazards, hazard categories, product categories, ...
[109]
FDA's Enforcement Actions Raise Broad Concerns Regarding ...
Aug 18, 2025 · Further, the federal agency has also rejected a number of shipments for undeclared sulfites and has continued actions taken last year to counter ...
[110]
Isolated Sulfite Oxidase Deficiency - GeneReviews® - NCBI Bookshelf
Sep 21, 2017 · Treatment of manifestations: No treatment exists for the underlying metabolic defect. Symptomatic treatment can include: anti-seizure ...
[111]
Isolated sulfite oxidase deficiency - Genetics - MedlinePlus
Jan 1, 2018 · Isolated sulfite oxidase deficiency (ISOD) is a disorder of the nervous system, with a severe "classic" form that starts in the newborn period.Missing: incidence | Show results with:incidence
[112]
Mutation analysis of SUOX in isolated sulfite oxidase deficiency with ...
Oct 27, 2022 · A deficiency in sulfite oxidase usually leads to severe and fatal neurological symptoms. The primary pathological signs are cortical swelling, ...
[113]
https://www.sciencedirect.com/science/article/abs/pii/S038776041930573X
[114]
Metabolic crisis after trivial head trauma in late-onset isolated sulfite ...
ISOD has two kind of presentation; early and late-onset. The late-onset form is extremely rare and only 10 cases have been reported.
[115]
Sulfite Oxidase Deficiency and Molybdenum Cofactor Deficiency
Feb 18, 2019 · The enzyme sulfite oxidase depends on the molybdenum-containing pterin cofactor, as do the enzymes xanthine dehydrogenase and aldehyde oxidase.