Acidulants and pH Adjusters: The History of Citric Acid, What Group Names Hide, Phosphates and the Kidneys, “Preservative-Free” Claims, and How Japan and the EU Label Them

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Curry roux, ponzu, bouillon cubes, Chinese soup base, convenience-store bento. Look at the ingredient list (原材料名) on the back and, in the additive section after the slash (/), you will often find “酸味料” (acidulant) and “pH調整剤” (pH adjuster).

But these two words do not tell you what is actually in the food. Common questions and claims include the following.

• What is in an “acidulant”? How is it different from vinegar or lemon juice?
• “pH adjusters are dangerous” and “they kill gut bacteria”
• Why does a “preservative-free” bento contain a pH adjuster?
• Are phosphates bad for the kidneys? Do they dissolve bones?
• How do other countries label the same thing?

This article uses government notices, minutes of study groups, statistics and papers to check:

• When and how acidulants such as citric acid came to be made
• When and why the “acidulant” / “pH adjuster” style of labeling (group names) was created
• What is inside the group names, and where they overlap
• How labeling differs in Japan, Codex (the international food standards body), the EU and the US
• Effects on the body: what research shows about phosphates and the kidneys and bones, and about citric acid and inflammation, fatigue and teeth
• How a government study group discussed the relationship between “preservative-free” and pH adjusters
• How acidulants and pH adjusters are written on the 71 products listed on Urayomi

Preservatives themselves are covered in the preservatives article, the rules for “additive-free” and “not used” claims in the article on the rules for “additive-free” labeling, and acetic acid in vinegar in the vinegar article.

Conclusion

• “Acidulant” and “pH adjuster” are “group names” (一括名): the name of the actual substance does not have to be written. Whichever and however many of the 24 designated additives (acidulant) or 35 designated additives (pH adjuster) are used (plus phytic acid, an existing additive, for both), the label can simply say “acidulant” or “pH adjuster”
• All 24 acidulant substances are also pH adjusters. The substances only in the pH adjuster list are 11, such as baking soda (sodium bicarbonate) and other alkaline substances, and sodium and potassium salts of phosphoric acid. The same glucono-delta-lactone is labeled under four different names depending on purpose: “acidulant”, “tofu coagulant”, “pH adjuster” and “leavening agent”
• Citric acid was isolated from lemon juice in 1784 and is now made by fermentation with a black-mold species. Japan began domestic production in 1953 in Kagoshima from sweet potato starch residue, but today imports dominate: 88.4% of the 57,210 tonnes imported in 2025 came from China
• The group-name system began in 1988, and “acidulant” and “pH adjuster” were among the first 11 names. In 2019-2020 a government study group even drafted Codex-style labels for comparison and concluded “keep the status quo”. Only 12.0% of consumers know that additives can be written together under a group name
• Codex, the EU and the US do not allow “pH adjuster” alone. The EU requires “category plus substance name or E number”, and the US requires the substance name. For the same Coca-Cola, the US official site lists “PHOSPHORIC ACID” while the Japanese official site lists only “酸味料” (acidulant)
• For citric, lactic and acetic acids, international evaluations say “ADI not limited” (ADI = acceptable daily intake). The source of “citric acid causes inflammation” was just four case reports. We could not find research behind “pH adjusters are dangerous” or “they kill gut bacteria”. What deserves attention is dental erosion from sipping acidic drinks for a long time
• Phosphates are a different story. Behind the group names are 6 phosphates under pH adjuster, 13 under kansui (alkaline agents for Chinese noodles) and 15 under leavening agent, but the label does not show them. The Japanese Society of Nephrology puts the absorption rate of inorganic phosphorus used in food processing at 90% or more. The information most needed by kidney patients who restrict phosphorus is the information group names hide most. On the other hand, for healthy people the link to heart disease or fractures is unclear
• Using a pH adjuster to extend shelf life while claiming “preservative-free” is listed in the government guidelines as an “example highly likely to mislead” (Type 4). In the study group, a convenience-store member said, based on what he heard from people in the industry, “Because preservatives have a bad image, [they are] switching to pH adjusters and glycine (…)”. In a small test of rice cooked at factories, no clear suppression of bacteria by pH adjusters was seen

What we introduce in this article

History of acidulants: from lemons to black mold, and then to imports

Today’s main acidulant is citric acid. After an era of extracting it from lemons and an era of making it with molds, Japan has gone around a full circle: “import, then domestic production, then import again”.

1784: citric acid is extracted from lemon juice

In 1784 the Swedish chemist Scheele extracted citric acid as crystals from lemon juice, and it was named after the lemon (citrus) (Ciriminna et al. 2017, a peer-reviewed review). Scheele also discovered lactic acid in sour milk in 1780. Industrial fermentation of lactic acid is said to have begun in 1881, but sources disagree on who started it (a French researcher or an American entrepreneur).

The lemon industry of Sicily

In the 19th century, citric acid was made from the lemon juice of Sicily, Italy. Lime was added to concentrated lemon juice to precipitate “calcium citrate”, which was then converted back with dilute sulfuric acid. Lemon-based production peaked at 17,500 tonnes in 1915-1916, and in 1930 Europe’s largest citric acid plant was in Palermo, Sicily (Ciriminna 2017).

1917: making citric acid with black mold

What changed the course was fermentation with molds.

We could not confirm Pfizer’s official company history. Here we only say that “within a few years of Currie’s discovery, Pfizer industrialized it”.

As fermentation spread, production from lemons declined. World citric acid production (including citrates) reached about 500,000 tonnes in 1989 and over 2 million tonnes in 2015, and in 2015 China accounted for 59% of world production and 74% of exports (Ciriminna 2017).

Japan’s citric acid: from Belgian imports to sweet potato residue in Kagoshima

Until the early 1950s, Japan’s citric acid was made mainly from imported Belgian citrate of lime (calcium citrate).

In 1953 (Showa 28), Uemura Chemical Industry in Kagoshima Prefecture completed a plant with an annual capacity of 160 tonnes that made citrate of lime by solid-state fermentation, using the sweet potato residue left after extracting starch (starch pulp) as the raw material. By 1962 four companies together made 2,000 tonnes a year, and demand for sourness in soft drinks and powdered juices was expected to be “well over 4,000 tonnes” (Matsumura 1963, Journal of the Japanese Society of Starch Science).

We could not confirm whether any company in Japan now makes citric acid by fermentation. What the statistics show is that imports keep growing, and most of them come from China.

Over 25 years imports grew about 1.8 times. The main non-China sources in 2025 were Austria and Thailand. These numbers include detergent and industrial uses and exclude salts such as sodium citrate. The 2025 value is the UN annual figure and has not been checked against the Ministry of Finance’s final data.

When substances were approved as additives in Japan

Many of the substances used as acidulants and pH adjusters were approved soon after the Food Sanitation Act was established (from the Japan Food Research Laboratories Foundation’s “History of designation and deletion”).

The first edition of the Japanese Standards of Food Additives (198 items), issued in March 1960, already listed citric acid, lactic acid, fumaric acid, tartaric acid, malic acid, phosphoric acid and acetic acid. The current edition is the 10th (2024).

1988: “group names” are created

The “acidulant” and “pH adjuster” style of labeling was born in the 1988 system revision, and both were among the first 11 names.

(From explanatory articles in Journal of the Brewing Society of Japan 1988 and Seikatsu Eisei 1990, and Consumer Affairs Agency study group materials. We could not confirm the original text of the 1988 notice itself.)

A 1990 explanatory article describes pH adjusters as “substances added to adjust the acidity of food, such as acetic acid, citric acid and baking soda”, and acidulants as “organic acids and their salts used to give sourness”. The group names took shape in trade negotiations, as an exception allowing “labeling together”, at the same time as the labeling system was expanding toward “write every additive”.

How are acidulants and pH adjusters different?

“Acidulant” is a group name for making food sour, and “pH adjuster” is a group name for keeping the degree of acidity or alkalinity. But many of the substances inside are the same.

What is pH?

pH is a number that shows how acidic or alkaline something is. 7 is neutral; lower numbers are more acidic and higher numbers are more alkaline. Lemon juice and vinegar are acidic, and water with baking soda dissolved in it is mildly alkaline.

Official definitions and scope

Source: Consumer Affairs Agency, “About the Food Labeling Standards”, Annex Additives 1-4 (April 1, 2026 version)

All 24 acidulant substances are also on the pH adjuster list

Cross-checking the government’s notice list, every one of the 24 acidulant substances is also among the 35 pH adjusters. The substances only in the pH adjuster list are these 11.

In other words, “pH adjuster” is a group name that does not only make things sour but may also move food toward the alkaline side. A respondent to the Consumer Affairs Agency study group’s survey also wrote, “I have never seen the contents of pH adjusters or leavening agents written, and it would be easier to understand if we could tell whether they adjust toward acidic or basic.”

Compared with a 1996 notice, the scope of pH adjusters has grown from 34 to 35 substances. The only addition is potassium lactate, designated in 2013.

The same substance goes by many names

Group names are decided by “purpose of use”, not by “substance”. So the same substance can be written differently on the label depending on its purpose. It is the manufacturer that decides the purpose.

Source: Urayomi’s tally from Consumer Affairs Agency Annex Additives 1-4

The same citric acid could be written “acidulant” in a juice, “pH adjuster” in a bento and “leavening agent” in pancake mix. With any of these, the name of the substance does not appear.

How are vinegar and lemon juice different from acidulants?

Even when the source of sourness is the same kind of acid, vinegar and lemon juice are treated as “food” and acidulants as “additives”.

Vinegar itself is a food, but “glacial acetic acid”, which is purified acetic acid, and “sodium acetate” are additives and fall under acidulant and pH adjuster.

Counting the 71 products listed on Urayomi, 20 products use vinegar such as brewed vinegar for sourness and 9 use juice such as lemon or yuzu. Some products, like Ajipon (味ぽん), use both “brewed vinegar” and “citrus juice” and also an “acidulant”.

Kawara Shuzo’s Roubai Organic Pure Rice Vinegar (老梅 有機純米酢) is a rice vinegar whose ingredient list has only one item: “organically grown rice (domestic)”. The label says that the “梅” (ume) in the trademark “老梅” means a traditional sour seasoning (no ume is among the ingredients). We introduce it for people who want to add sourness to cooking with vinegar rather than additives. The types of vinegar and the conditions for writing “pure rice vinegar” (純米酢) are covered in the vinegar article.

Labeling rules: Japan, Codex, the EU and the US

In Japan it is enough to write “acidulant” or “pH adjuster”, while the main overseas systems require a substance name or a number.

Japan: additives written by purpose, and additives that may be grouped

Additive labeling in Japan is, in principle, by substance name. In addition:

• For 8 purposes (sweetener, colorant, preservative, thickener etc., antioxidant, color fixer, bleaching agent and antifungal agent), there is an obligation to write the purpose and the substance name side by side, as in “preservative (potassium sorbate)”
• For 14 group names such as acidulant, pH adjuster, emulsifier, flavoring and seasoning, it is allowed to write only the group name instead of the substance name (it is not an obligation)

The Q&A on the Food Labeling Standards also allows adding the contents after the group name, as in “acidulant (citric acid, etc.)”. The conditions are that the substances are within the scope, are in order of weight, and that when several are used it is not written as if there were only one.

When an acidulant used at the raw-material stage is not present in an amount that works in the finished food, it may not be labeled at all. See the carry-over article for details.

12.0% know about group names

In a Consumer Affairs Agency survey of 10,000 people (fiscal 2017),

This means only about one in ten people knows that “acidulant” is not the name of a single substance.

The Consumer Affairs Agency advises people who want to know what is in an additive written under a group name to contact the manufacturer or seller named on the label.

The government study group chose to “keep the status quo”

The Consumer Affairs Agency’s “Study Group on the Food Additive Labeling System” (2019-2020) discussed whether to review group names. In the study group’s materials, the label of the same bento is compared in three ways.

(Labeling examples from the Consumer Affairs Agency study group materials. The bento is a hypothetical example.)

The conclusion was that “keeping the status quo is appropriate”. The reasons were that group names have been used for more than 30 years, that labels would get longer, and that international numbers (INS numbers) are unfamiliar to consumers. In exchange, businesses are expected to respond politely to inquiries and to provide information on websites.

However, a 2019 survey found that the only group names for which websites listed the substance names were tofu coagulant and bittering agent.

Labeling in Codex, the EU and the US

Source: Codex General Standard for the Labelling of Prepackaged Foods (provisional translation by the Consumer Affairs Agency), EU Regulation 1169/2011 Annex VII, US Code of Federal Regulations 21 CFR 101

The main EU numbers are E330 citric acid, E270 lactic acid, E296 malic acid, E297 fumaric acid, E260 acetic acid, E338 phosphoric acid, E339-E341 sodium, potassium and calcium salts of phosphoric acid, E450-E452 di-, tri- and polyphosphates, and E575 glucono-delta-lactone. In the EU it is not possible to write just “pH adjuster”.

The same cola is “PHOSPHORIC ACID” in the US and “acidulant” in Japan

The difference between systems is easy to see in the drinks of the same brand (checked October 3, 2026).

In the US it is written “phosphoric acid”. In Japan it is written only “acidulant”, and even the FAQ page of Coca-Cola Japan explains it only as “acidulant”. We could not confirm from official Japanese materials whether the acidulant in cola sold in Japan is phosphoric acid. What we can say is that “for drinks with the same name, the US label shows phosphoric acid, and the Japanese label does not”. Caramel color is covered in the caramel color article.

Are acidulants and pH adjusters bad for you?

Citric, lactic and acetic acids, the core of acidulants, are substances for which international evaluations found no need to set an upper limit. Phosphates, on the other hand, are a different matter for people whose kidney function has declined.

Evaluations by international bodies

ADI (acceptable daily intake) is the amount thought to cause no harm to health even if taken every day for a lifetime. Sources: notes in the 12th report of the MHLW-funded research on production statistics; EFSA 2019, 2020

What does “ADI not limited” mean?

“Not limited” and “not specified” mean that toxicity is very low and, at the amounts needed to achieve the intended effect, there is no health concern, so there is no need to set a numerical ADI (the definition in EFSA guidance). It does not mean “any amount is fine”; it assumes “use only the amount that is needed”.

Re-evaluations can move standards in a stricter direction or a looser one. For phosphates, the standard went from JECFA’s 70 to EFSA’s 40, which is stricter, and for tartaric acid it rose eightfold from 30 to 240 (because humans absorb tartaric acid less readily than rats do). “Re-evaluated” does not mean “a danger was found”.

How much do we take in as additives?

This is an estimate by a government research group, which gathered shipment volumes for food use from a survey of manufacturers and importers and divided them into per-person, per-day amounts (fiscal 2016).

• Citric acid is 483 mg per person per day, about 2.1 times the figure from the survey of the late 1980s (230.8 mg)
• Next are sodium acetate at 190 mg, trisodium citrate at 173 mg, sodium bicarbonate at 158 mg and lactic acid at 90 mg
• These are amounts per substance, so you cannot tell whether they were used as an acidulant, pH adjuster, seasoning or leavening agent. Amounts naturally present in fruit and the like are not included

The research work was commissioned to an industry group (the Japan Food Additives Association), and the data are the manufacturers’ own reports.

Phosphates: EFSA set an ADI in 2019

Phosphates (phosphoric acid, sodium phosphates, pyrophosphates, polyphosphates, etc.) are used in acidulants and pH adjusters, in kansui and leavening agents, and as binders in ham and sausage. Phosphorus is also a mineral the body needs.

In 2019 EFSA re-evaluated phosphates and set a group ADI of “40 mg per kg of body weight as phosphorus”. For a 70 kg adult that is 2,800 mg a day.

• The basis is the amount at which no effects such as calcium deposits in the kidneys were seen in long-term rat studies, multiplied by an additional safety factor
• This ADI applies to the total phosphorus from the whole diet, not only the additive portion
• EFSA states that it “does not apply to people with moderately to severely reduced kidney function” and writes that about 10% of the general population may have chronic kidney disease (CKD)
• By EFSA’s calculation, on average infants, toddlers and children in Europe, and high consumers among adolescents, exceeded the ADI. Still, the conclusion was that “healthy adults are protected”, and EFSA recommended that its own Scientific Committee review how reference values are set for substances that are also nutrients
• It also writes that “total phosphorus content is not required on food labels”

The European phosphate industry association also submitted data for the evaluation.

How much phosphorus do Japanese people take in?

What stands out is that the MHLW itself writes in the Dietary Reference Intakes 2025 that “the values in the National Health and Nutrition Survey do not take into account the amount of phosphorus added to processed foods”. For that reason, actual intake may be higher, and the adult adequate intake is taken from the lowest of the medians across age groups. The contribution of additives is described as “unknown”.

How many mg of phosphorus come from additives? Estimates differ greatly by method

The Food Safety Commission of Japan judges that additive-derived phosphorus is “about 50 mg/day”, which raises the roughly 1,000 mg in the National Health and Nutrition Survey by only a few percent on average. The 248 mg figure also includes phosphorus naturally present in processed foods, so it is not the additive amount alone.

The same report also introduces a study of 16 types of convenience-store bento in which the calculated phosphorus per meal averaged 259 mg and the measured amount averaged 320 mg, so that the measured value was about 60 mg (61 mg) higher (Tanizaki et al. 2017, Micronutrient Research; we could not confirm the original paper). Cooking usually reduces phosphorus, so the measured value should be lower, which suggests there is phosphorus that the calculation does not include.

Absorption: inorganic phosphorus used in processing is 90% or more

Not all the phosphorus we take in is absorbed by the body. The Japanese Society of Nephrology’s “Dietary Therapy Standards for Chronic Kidney Disease, 2014 edition” gives:

EFSA gives the absorption of phosphorus naturally in food as a range of 55-90%, and says that inorganic phosphate additives are “about 80-90% absorbed” and “efficiently absorbed”. Even if the amount is small, additive phosphorus is “well-absorbed phosphorus”.

People with kidney disease cannot tell what is inside from group names

We counted the phosphates in each group name from the government notice list.

Of the 16 substances allowed as kansui for Chinese noodles, 13 (about 80%) are phosphates, yet the back label says only “かんすい” (kansui). For pH adjusters, leavening agents and acidulants as well, you cannot tell from the label whether phosphates are used. In addition, “seasoning (inorganic salts)” (調味料（無機塩）) includes 6 phosphates, and “emulsifier” used in processed cheese includes 19.

When kidney function declines, it becomes harder to excrete phosphorus in the urine. The Japanese Society of Nephrology’s standard gives a guideline for people on dialysis of “phosphorus (mg) ≦ protein (g) × 15”. For the conservative stage (before dialysis), it is considered together with protein guidance and evaluated against test values.

The Dietary Reference Intakes 2025 also say that, although there is a view that limiting phosphorus from the early stages of kidney disease is desirable, “the scientific basis for from which stage and how much to restrict is not sufficient”.

Note that on Japanese nutrition labels, phosphorus is an item that may be written (optional), not a mandatory one. It is not that “there is no place to write phosphorus” but that “it need not be written”.

How much phosphorus or protein restriction is needed differs for each person depending on the stage of the disease and test values. Please follow the instructions of your doctor and registered dietitian rather than deciding dietary restrictions yourself. With that in mind, there are also meal-delivery services that adjust phosphorus and protein.

In healthy people? The link to heart and blood vessels is not consistent

For people with normal kidney function, no clear conclusion has been reached.

• EFSA (2019) concluded that the relationship between dietary phosphorus and cardiovascular disease is not consistent in observational studies. It also names a limitation: food composition tables do not include additive phosphorus, so intake is underestimated
• The often-cited US study that “taking 1,400 mg or more of phosphorus a day raises the risk of death” (Chang et al. 2014, following 9,686 people) received a correction in 2017, which withdrew the association with death from cardiovascular disease. Be careful with articles that quote only the abstract
• There is a summary showing that people with higher blood phosphorus are more likely to die of cardiovascular disease (7 cohorts, 41,764 people). However, blood phosphorus is tightly regulated by the kidneys and is a different thing from the amount eaten

A US survey estimated added phosphorus for adults at 155 mg a day (11.6% of the total) (Fulgoni 2021), but that study was funded by a food additive industry association, which also provided data and reviewed the manuscript.

“Too much phosphorus dissolves bones”?

• A meta-analysis of 12 intervention studies with 269 people (Fenton et al. 2009) found that increasing phosphate actually decreased urinary calcium and improved calcium balance. The idea that “acidic foods dissolve bones” was not supported (no industry funding)
• On the other hand, in the US Framingham study (a cross-sectional study of 2,538 people), women who drank cola every day had 3.7-5.4% lower bone density at the hip (femoral neck, etc.) than women who drank less than one a month. There was no relationship for other carbonated drinks, and none in men. Whether the cause is phosphoric acid, caffeine or drinking less milk is not known
• The Dietary Reference Intakes 2025 also say, “Human studies on the relationship between high phosphorus intake and loss of bone mass are not sufficient”

“Acidulants cause cancer”?

Among the sources we examined, we found no evaluation by a public body showing that the substances used as acidulants cause cancer. For tartaric acid, EFSA’s re-evaluation states that there were no signs of cancer even in animal studies at the highest dose.

For phosphates, there is an animal study in which lung-cancer mice fed a high-phosphorus diet had more tumors, but the same research group reported that tumors also increased on a low-phosphorus diet. There are also studies showing a relationship between human prostate cancer and phosphorus intake, but that is phosphorus from the whole diet including dairy products and is not about additives.

“Industrial citric acid causes inflammation”?

The source of the story that “citric acid made with black mold causes inflammation” is four case reports published by American physicians in 2018 (Sweis & Cressey 2018).

• Four people reported joint pain, muscle pain, shortness of breath and abdominal symptoms 2-12 hours after eating or drinking something containing citric acid
• There was no blinded challenge test, no comparison with a placebo, and no measurement of impurities in the citric acid
• The authors themselves write that “causation cannot be concluded” and that “double-blind trials are needed”

All we can say is that “there is a report that proposed such a hypothesis”.

“Citric acid relieves fatigue”?

The representative trial is a crossover trial in which 18 healthy people took 2,700 mg of citric acid a day for 8 days (Sugino et al. 2007). The “feeling of fatigue” after exercise and a salivary stress marker went down.

However, it involved 18 people for 8 days with mainly self-rated results, the authors were affiliated with a contract research organization, and no funding is stated. 2,700 mg a day is about 5.6 times the estimated additive intake (483 mg). It is not a basis for expecting fatigue relief from the amount of acidulant in food.

Dental erosion: strength and frequency of acid

“Dental erosion” (酸蝕症) is the dissolving of the tooth surface by acid. Unlike cavities, bacteria are not involved.

• When 379 drinks sold in the US were measured, 93% were below pH 4.0 and 39% were below pH 3.0 (Reddy et al. 2016). Citric acid binds calcium, so it can dissolve teeth even at a higher pH
• In a survey of 1,108 adults in Tokyo, 26.1% showed signs of erosion, and it was related to how often younger people drank sour juice and how often older people ate sour fruit (Kitasako et al. 2015; 26.1% is the abstract’s figure. A correction was issued in December 2015, but we could not confirm what it changed)

Acids are naturally present in lemons and vinegar too, so it is not “because it is an additive” that teeth dissolve. The problem is sipping a low-pH drink slowly over a long time. Cautions about drinking vinegar are also in the vinegar article.

“pH adjusters are dangerous” and “they kill gut bacteria”?

We could not trace the origin of either claim, and we found no human research that supports them.

• In the government definition, a pH adjuster is an additive for “keeping food in a suitable pH range”. It is sometimes used in bento and similar foods to extend shelf life, which may be what leads people to associate it with “killing bacteria” (this is our guess)
• In an 8-week RCT in which 62 healthy adults took an extra 1,000 mg of phosphorus a day as sodium phosphate (Trautvetter et al. 2018), fecal toxicity did not change. Short-chain fatty acids made in the gut increased in the group that also took more calcium, and the composition of gut bacteria changed in men, but these are only “leads”
• A study showing that the amount of acidulant in food reduces human gut bacteria was not found in the range we searched on PubMed

Some emulsifiers (CMC and polysorbate 80) have been studied for effects on gut bacteria, and the stories may be getting mixed up. See the emulsifier article for details.

Verdicts on the claims

“Preservative-free” but with a pH adjuster?

In bento and prepared foods, pH adjusters and glycine are sometimes used instead of preservatives to help keep food longer. The government guidelines list labels that hide this and say “preservative-free” as examples highly likely to mislead.

The difference between preservatives and shelf-life extenders is covered in the preservatives article, and the full set of 10 types in the guidelines in the article on the rules for “additive-free” labeling. Here we introduce material not covered in those articles, from the study group’s minutes and surveys.

Why does a pH adjuster extend shelf life?

Many bacteria grow readily in near-neutral conditions and less readily when it is acidic. Preservatives such as sorbic acid and benzoic acid also work better under acidic conditions, so it is common to use a pH adjuster together with them to make the food acidic (Hiroshima Prefecture Food Industry Technology Center).

Type 4 and Type 7 in the guidelines

The Consumer Affairs Agency’s “Guidelines on Labeling of Non-Use of Food Additives” (March 2022) include these examples.

The guidelines say that these are “highly likely to fall under prohibited labeling”. Some explanations say flatly that they are “banned”, but the wording of the guidelines is “highly likely”.

Statements recorded in the study group’s minutes

The minutes of the study group that drafted the guidelines (2021) record specific exchanges about pH adjusters.

• Meeting 6 (November 2021): A member from a major convenience-store chain (Seven-Eleven), drawing on his experience talking with people in the industry who add a “please eat promptly” notice, said in substance that because preservatives have a bad image, as they switch to pH adjusters and glycine, quality after opening certainly deteriorates faster. Another member suggested that one could write, “No preservatives are used, but a pH adjuster is used to enhance preservation; since this is not sufficient, please eat promptly”
• Meeting 7 (December 2021): The secretariat (Consumer Affairs Agency) replied that if a shelf-life extender or pH adjuster is used instead of a preservative, it may fall under Type 4, and writing “please eat promptly” may also fall under Type 7. It also explained that when neither a preservative nor an additive for shelf life is used, a different type (Type 8) may apply
• In the same meeting, a dissenting view was also raised: “Glycine is not classified as a preservative, so is it really so wrong to write ‘preservative-free’ as a matter of fact? It is hard for businesses to understand”
• Meeting 2 (May 2021): A soft drink industry association explained that there are a few examples where drinks that originally have a low pH and need no preservative carry the label “preservative-free”

Seven-Eleven cut “not used” labels to about 20%

At the third study group meeting (July 2021), Seven-Eleven explained that:

• For “fresh food” such as bento and rice balls, it has in principle stopped advertising “no preservatives or synthetic colorants”
• The number of private-brand (Seven Premium) items carrying a “not used” label is about 20% of what it was in 2019

At the same meeting, AEON’s Topvalu cited “what is a pH adjuster, and is it harmless?” as an example of additive questions it receives from customers.

How do consumers take it?

This is a Consumer Affairs Agency survey (fiscal 2020) asking how people feel if a product labeled “no preservatives used” turned out to use a shelf-life extender.

About 70% (70.8%) chose something other than “no problem”. Among people who buy based on “not used” labels, 54.1% also look at the ingredient list on the back.

How long does a pH adjuster keep food? A test on cooked rice

There is a test that examined rice cooked at factories, by the Osaka Institute of Public Health (大阪健康安全基盤研究所) and others (Umeda et al. 2022, Japanese Journal of Food Microbiology).

• They examined 7 samples of rice from 6 rice-cooking factories (3 with pH adjuster, 4 without). The pH adjusters used were preparations of lactic acid, sodium lactate and adipic acid; of sodium acetate, gluconic acid and citric acid; and of citric acid and others
• The pH on arrival was 6.8-6.9 without pH adjuster and 5.3-6.2 with it
• When kept at 35°C, under the conditions of this test, no clear suppression of bacteria by pH adjusters was seen
• When a small amount of Staphylococcus aureus was added, it grew greatly in 24 hours and produced the toxin that causes food poisoning. Staphylococcus aureus can grow at pH 4-9.6, and the rice with pH adjuster also fell in this range

The authors conclude, “Do not overestimate the effect of additives such as pH adjusters; manage temperature and time.” This is a small test with only 7 samples, with just 3 samples containing pH adjuster (and 3 kinds of preparations), so it does not apply to all foods. Still, it shows that it is better not to assume that “it contains a pH adjuster, so it will not spoil easily”.

What to check when choosing prepared foods and bento

• Even if “preservative-free” is written, look at the part after the “/” in the ingredient list for pH adjuster, glycine, sodium acetate and the like
• For bento and prepared foods, follow the storage method on the label (10°C or below, etc.) and eat them soon. Even with a pH adjuster, temperature control matters (see the rice test above)
• If you want to know the contents, contact the manufacturer or seller on the label

For people who want to choose side dishes by ingredients, there is a frozen prepared-meal delivery service that uses domestic ingredients and describes its cooking as “additive-free” (無添加調理). Comparisons of food delivery services are in the food delivery comparison article.

Counting on Urayomi

From here on is our own tally, combining Urayomi’s data with public figures.

Of 71 products, 10 say “acidulant”, and 0 name the substance

We recounted the ingredients of the 71 foods and seasonings listed on Urayomi (as of October 3, 2026).

• The products with “acidulant” were Cook Do for twice-cooked pork (回鍋肉用), Ajinomoto KK Consomme (味の素KKコンソメ), Java Curry (ジャワカレー), Kokumaro Curry (こくまろカレー), Stew Mix (シチューミクス), Vermont Curry (バーモントカレー), Ajipon (味ぽん), Nissin Deka-Uma Abura Soba (日清デカうま油そば), Golden Curry (ゴールデンカレー) and Soubi Shantan (創味シャンタン)
• Of the 11 curry and stew roux, 5 have “acidulant”, and these are all 5 from the big makers (House Foods and S&B Foods). For example, House Vermont Curry, medium hot (ハウス バーモントカレー 中辛) uses “acidulant” in addition to apple paste and tomato powder. The other 6 (Cosmo Foods (コスモ食品), M-to-M (エム・トゥ・エム) and Sokensha (創健社)) have no acidulant. For example, the ingredients of Cosmo Naoyaki Curry Roux, medium hot (コスモ直火焼 カレー・ルー 中辛) contain no acidulant and include tomato paste, chutney and apple puree. The ingredients of curry roux are compared in detail in the curry roux article
• “pH adjuster” appears in one product, Marudori Gara Soup (丸鶏がらスープ). Ajinomoto’s official Q&A answers the question “What is a pH adjuster?” with its purpose only and does not give substance names
• Adding “kansui” (2 products) and “leavening agent” (膨脹剤, 1 product), 13 products (18%) have at least one of the four group names that may contain phosphates (acidulant, pH adjuster, kansui and leavening agent). Of these, not a single product shows from its label whether phosphates are used (phosphates may also be in “seasoning (amino acids, etc.)” (調味料（アミノ酸等）) and “emulsifier”, but we have not counted those here)

Under the government rules, the contents can be added, as in “acidulant (citric acid, etc.)”. The government study group said, “instead of keeping the status quo, businesses should make an effort to provide information”, but among Urayomi’s 71 products, not a single one adds the contents.

Recalculating for Japanese children with EFSA’s standard

We applied EFSA’s ADI (40 mg of phosphorus per kg of body weight) to the intake of Japanese people.

For ages 1-6, average intake almost reaches EFSA’s ADI. Please note the following, however.

• Intake (2023 National Health and Nutrition Survey) and body weight (fiscal 2021 market basket study) are values from different surveys. For ages 20-29 we used the average body weight of those aged 20 and over
• The intake figures hardly include additive phosphorus (MHLW). Actual intake may be somewhat higher
• In the first place, the government’s adequate intake of phosphorus for ages 3-5 is 700 mg a day, which is more than the 660 mg calculated with EFSA’s standard

This is the same thing EFSA itself wrote, that “toddlers and children in Europe exceed the ADI on average”, happening in Japan too. Phosphorus is also a nutrient the body needs, so this does not mean that “children are taking a dangerous amount of phosphorus”. It is a number that shows the difficulty of applying an additive yardstick (ADI) to a substance that is also a nutrient. This is also why EFSA asked for a review of how its own standards are set.

Back-label checkpoints

• “Acidulant” and “pH adjuster” are group names, not substance names. They come after the “/”, and are written in a single word however many substances are used
• The main contents (citric acid, lactic acid, acetic acid, etc.) are substances for which international evaluations say “ADI not limited”. You do not need to worry just because they are written
• If you restrict phosphorus, watch for “pH adjuster”, “kansui”, “leavening agent” and “acidulant”, and for processed foods such as ham, sausage and fish paste products (phosphates may also be in “seasoning” and in the “emulsifier” of processed cheese). You cannot tell from the label whether they are phosphates, so contact the manufacturer if needed. Follow your doctor’s and registered dietitian’s instructions on dietary restrictions
• “Preservative-free” does not mean that no additive for shelf life is included. Check for pH adjuster, glycine, sodium acetate and the like
• If you want to add sourness with food, choose products that have “brewed vinegar”, “rice vinegar”, “lemon juice” or the like before the “/” and no “acidulant”
• Do not sip sour drinks for a long time. It can cause dental erosion

What we introduced in this article (summary)

Here is a recap of what we introduced. The reasons and ingredients are in each section.

What we introduced	Where to buy
河原酢造 老梅 有機純米酢 500ml (Kawara Shuzo Roubai organic pure rice vinegar, 500 ml)	See on Rakuten (楽天24) PR See on Amazon.co.jp PR See on Yahoo! Shopping PR
Dr.つるかめキッチン (Dr. Tsurukame Kitchen: meal delivery for restricted diets, supervised by medical specialists and registered dietitians)	Dr.つるかめキッチン（制限食の宅配弁当）を見る PR
FIT FOOD HOME (frozen prepared-meal delivery)	【国産素材】無添加調理“FIT FOOD HOME”。 PR

Summary

Sources

History and production

• Ciriminna R, et al. Citric acid: emerging applications of key biotechnology industrial product. Chem Cent J 2017;11:22 (PMID 28326128)
• Cairns TC, et al. How a fungus shapes biotechnology: 100 years of Aspergillus niger research. Fungal Biol Biotechnol 2018;5:13 (PMC5966904)
• Currie JN. The citric acid fermentation of Aspergillus niger. J Biol Chem 1917;31:15-37
• Książek E. Citric Acid: Properties, Microbial Production, and Applications in the Food Industry—A Review. Molecules 2023;29(1):22 (PMC10779990)
• Review of lactic acid fermentation (Rhizopus), 2025 (PMC12675874)
• Matsumura H. “On the citric acid fermentation industry using starch pulp as raw material”. Journal of the Japanese Society of Starch Science 1963;10(2):98
• Japan Food Research Laboratories Foundation, “List of additives: history of designation and deletion” (January 2021)
• MHLW and Consumer Affairs Agency, “The Japanese Standards of Food Additives, 10th edition”, brief history (2024)
• UN Comtrade (Japan’s imports, HS 2918.14, 2000-2025)

Group names and labeling system

• “Trends in food additive labeling”, Journal of the Brewing Society of Japan 1988;83(10):660; Kawai N. “Food additive labeling has changed”, Seikatsu Eisei 1990;34(5):241
• Ministry of Health and Welfare, Eika No. 56 (May 23, 1996)
• Consumer Affairs Agency, “About the Food Labeling Standards”, Annex Additives 1-4 and Annex Additives 2-1 (April 1, 2026 version); “Food Labeling Standards Q&A”, processed foods (October 1, 2026 version)
• Consumer Affairs Agency, Study Group on the Food Additive Labeling System, materials (April, August and November 2019) and report (March 2020)
• Takahashi T. “On the report of the Study Group on the Food Additive Labeling System”, ALIC Sugar and Starch Information (July 2020)
• Consumer Affairs Agency, “Tips on food additive labeling” (April 2026 edition)
• Codex General Standard for the Labelling of Prepackaged Foods (provisional translation by the Consumer Affairs Agency)
• EU Regulation 1169/2011 Annex VII Part C; UK Food Standards Agency, “Approved additives and E numbers”
• US Code of Federal Regulations 21 CFR 101.4, 101.22, 172.350, 182.1073, 184.1005, 184.1033, 184.1061, 184.1069
• Coca-Cola Japan, product information and FAQ; The Coca-Cola Company, “Coca-Cola Original” product page (checked October 3, 2026)

“Preservative-free”

• Consumer Affairs Agency, “Guidelines on Labeling of Non-Use of Food Additives” (March 30, 2022)
• Consumer Affairs Agency, Study Group on the Guidelines on Labeling of Non-Use of Food Additives, minutes of meetings 2, 3, 6 and 7 (2021); materials for meeting 3 (fiscal 2020 consumer opinion survey)
• Umeda K, et al. “Investigation of food poisoning risk from rice cooked at factories”, Japanese Journal of Food Microbiology 2022;39(2):70
• Hiroshima Prefecture Food Industry Technology Center, “On ‘preservatives’ and ‘shelf-life extenders’”

Effects on the body

• EFSA FAF Panel. Re-evaluation of phosphoric acid–phosphates – di-, tri- and polyphosphates (E 338–341, E 343, E 450–452). EFSA J 2019;17(6):5674 (PMID 32626329)
• EFSA FAF Panel. Re-evaluation of L(+)-tartaric acid (E 334) and its salts. EFSA J 2020;18:6030 (PMID 32874248)
• EFSA Scientific Committee guidance (2026, PMC12817064)
• MHLW, “Dietary Reference Intakes for Japanese (2025 edition)”, “2023 National Health and Nutrition Survey Report”, “Fiscal 2021 market basket study of intake of preservatives, etc.”
• Food Safety Commission of Japan, “Survey on collecting information for exposure assessment of food additives” (March 2023)
• MHLW-funded research, “Study on estimating food additive intake based on production volume statistics, Part 1: designated additives (12th final report)” (March 2020)
• Japanese Society of Nephrology, “Dietary Therapy Standards for Chronic Kidney Disease, 2014 edition”
• Sullivan C, et al. JAMA 2009 (PMID 19211470) / Benini O, et al. J Ren Nutr 2011 (PMID 21055967) / León JB, et al. J Ren Nutr 2013 (PMID 23402914) / Liu Z, et al. Cochrane 2015 (PMID 26376110)
• Chang AR, et al. Am J Clin Nutr 2014 (PMID 24225358), correction 2017 (PMID 28373320) / Torrijo-Belanche C, et al. 2024 (PMID 38892532) / Fulgoni K, Fulgoni VL. 2021 (PMID 34210102)
• Fenton TR, et al. Nutr J 2009 (PMID 19754972) / Tucker KL, et al. Am J Clin Nutr 2006 (PMID 17023723)
• Jin H, et al. 2009 (PMID 18849498) / Xu CX, et al. 2010 (PMID 20432174) / Wilson KM, et al. 2015 (PMID 25527761)
• Sweis IE, Cressey BC. Toxicol Rep 2018;5:808-812 (PMID 30128297)
• Sugino T, et al. J Clin Biochem Nutr 2007 (PMID 18299720)
• Reddy A, et al. J Am Dent Assoc 2016 (PMID 26653863) / Kitasako Y, et al. J Dent 2015 (PMID 25684603)
• Trautvetter U, et al. Nutr J 2018 (PMID 29452584)

Urayomi’s data

• Ingredients of the 71 product pages on Urayomi (as of October 3, 2026, tallied by Urayomi)
• Ajinomoto, “Maru-dori Gara Soup” customer service Q&A, “What is a pH adjuster?” (ｐH調整剤とは何ですか。)