E240 – Formaldehyde | why it is no longer an EU food preservative

Quick analysis summary about E240 – Formaldehyde food additive

Bottom line about E240

E240 is a former formaldehyde preservative that is not currently authorised as a food additive in the EU, so it is graded RED – UNSAFE.

Why this grade for E240

The grade is driven by current non-authorisation after historical preservative use was not retained, while high-dose oral studies also show substantial stomach injury [1,2].

Who may want to limit or avoid E240

Consumers should avoid products that deliberately list E240 as a food preservative, while naturally occurring trace formaldehyde in ordinary foods is a different exposure scenario.

Common uses and where E240 appears

E240 was historically used to suppress spoilage organisms in cheese and formaldehyde still has narrow processing roles in the US that do not amount to general preservative approval.

E240 source or origin

Intentional E240 is synthetic formaldehyde, although formaldehyde also occurs naturally in foods and normal metabolism [3].

Intake note for E240

No current EU ADI (Acceptable Daily Intake) applies to E240 as an authorised food additive because formaldehyde is not authorised for that use.

Is E240 banned anywhere?

E240 is not authorised as a food additive in the EU. The US permits formaldehyde only in narrowly defined processing uses such as preservation of certain defoaming agents, not as a general E240-style food preservative.

Safety grading RED – UNSAFE

E240 is graded RED – UNSAFE because formaldehyde is not currently authorised as an EU food additive after earlier preservative use was officially recognised but later not retained. This grade concerns deliberate E240 preservative use and does not mean that every natural trace of formaldehyde in food carries the same risk.

Study basis or key toxicological reasoning for E240

In a four-week rat drinking-water study, 25 mg/kg body weight per day was the NOAEL (No Observed Adverse Effect Level), while 125 mg/kg body weight per day caused forestomach hyperkeratosis and focal gastritis [1]. In a two-year study, the NOAEL was about 15 mg/kg body weight per day in males and 21 mg/kg body weight per day in females. High doses of 82 and 109 mg/kg body weight per day caused severe gastric mucosal damage without increased tumours [2]. A separate 24-month study found no toxicological abnormality at about 10 mg/kg body weight per day, while the highest concentration caused erosions, ulcers and hyperplasia [4]. These studies show clear dose-related local gastrointestinal toxicity, but they do not establish that normal dietary traces cause the same effects.

Side effects of E240 – Formaldehyde food additive

Stomach irritation and injury can occur at high oral doses. Rat studies reported gastritis, hyperkeratosis, erosions, ulcers and mucosal hyperplasia at sufficiently high exposure [1,2,4].
Local genotoxic effects were reported at a severely irritating dose. Rats given 200 mg/kg orally developed increased micronuclei and nuclear abnormalities in gastrointestinal tissues together with marked local irritation [5].
Cancer-related evidence is mixed for oral exposure. One high-dose rat model showed tumour-promoting activity in the stomach [6], and a lifetime study reported increased malignant tumours [7], while two conventional chronic drinking-water studies did not show increased tumour incidence [2,4].
The strongest human cancer evidence concerns inhalation. Formaldehyde is recognised as a human carcinogen mainly from occupational exposure, which is not the same exposure route as trace formaldehyde in food.

Should You Avoid E240 – Formaldehyde food additive?

Food deliberately preserved with E240 should be avoided because this use is not currently authorised in the EU. That conclusion should not be extended to normal foods simply because they contain naturally occurring formaldehyde at trace levels. The main dietary concern is intentional preservative use or unusually high exposure, not the mere presence of tiny endogenous or naturally occurring amounts.

Common uses of E240 – Formaldehyde food additive

Historically in Grana Padano cheese, where it was used to help control gas-forming spoilage organisms.
Historically as an antimicrobial preservative in food processing.
In the US, as a preservative in certain defoaming agents containing dimethylpolysiloxane.
In the US, as a preservative component of certain defoaming agents used in beet-sugar and yeast processing.

Common names and synonyms of E240 – Formaldehyde food additive

Formaldehyde
Methanal
Oxymethylene
Formalin, meaning an aqueous formaldehyde solution rather than pure formaldehyde

What is E240 – Formaldehyde food additive?

Formaldehyde is the simplest aldehyde, with the chemical formula CH2O and CAS number 50-00-0. At room temperature pure formaldehyde is a reactive gas. Industrial formaldehyde is usually produced from methanol, but the molecule is also formed naturally during normal biological metabolism.

Its antimicrobial action explains its former preservative use. In cheese, formaldehyde reacts readily with proteins and amino-acid residues rather than remaining entirely as free formaldehyde. A food-specific review described this chemistry and also noted naturally occurring formaldehyde in several foods [3]. This distinction is important because the E240 safety grade concerns deliberate use as a preservative, not every molecule of formaldehyde that can occur naturally.

Reproductive evidence relevant to food exposure is comparatively limited. In an inhalation study, pregnant rats exposed to 20 or 40 ppm had reduced fetal weights, while clear malformation or embryonic-lethality patterns were not seen [8]. Because the exposure route was inhalation, this result is indirect for dietary E240.

Where is E240 – Formaldehyde food additive allowed (EU vs US)?

E240 is not currently authorised as a food additive in the EU after historical formaldehyde preservative use was not retained. In the US, formaldehyde has narrowly defined permitted roles in certain food-processing defoaming agents, but this is not approval as a general preservative in finished foods.

E240 – Formaldehyde