E-numbers / Other additives / E342

Ammonium phosphates

also: Monoammonium phosphate · Diammonium phosphate · Ammonium orthophosphate · MAP

A mineral salt used as a leavening agent in baked goods, helping dough rise and controlling acidity during baking.

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E342

Ammonium phosphates

This is not on the UK list of approved food additives, so you will not normally see this E number on a UK label.

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What ammonium phosphates is, what it does and where you will see it

Why it’s worth knowing. This is not on the UK list of approved food additives, so you will not normally see this E number on a UK label.

What is it?

Ammonium phosphates are salts formed from phosphoric acid and ammonia. The two forms permitted as food additives are monoammonium phosphate (E342i) and diammonium phosphate (E342ii). Both are white crystalline powders soluble in water.

What does it do?

Acts primarily as a leavening agent: when heated, ammonium phosphates release ammonia gas and carbon dioxide, causing baked goods to rise. Also used as an acidity regulator and yeast nutrient (diammonium phosphate is a nitrogen source that feeds yeast during fermentation). In very small quantities it can buffer pH in doughs and batters.

Where you will see it

Found mainly in bread, biscuits, crackers, wafers, and pastries. Diammonium phosphate is also used in winemaking as a yeast nutrient. On a UK ingredient label it appears as 'ammonium phosphates', 'E342', or its sub-forms 'E342(i)' and 'E342(ii)'.

What the science says

Phosphate intake from food additives

Ammonium phosphates contribute to overall dietary phosphate intake. High total phosphate consumption, primarily from phosphate additives across many processed foods, has been associated in observational studies with poorer cardiovascular and kidney outcomes, particularly in people with existing kidney disease. However, the contribution from E342 specifically is small relative to phosphates found naturally in meat, dairy, and grains.

Elevated serum phosphate, driven partly by inorganic phosphate additives, is associated with increased cardiovascular mortality in people with chronic kidney disease (CKD) in observational cohort data.

2004ObservationalBlock et al., Journal of the American Society of Nephrology

EFSA's Panel on Food Additives and Nutrient Sources (ANS Panel) reviewed phosphates as a group and concluded that exposure from their combined use across food categories warrants monitoring, while noting that natural dietary phosphate substantially exceeds additive-derived phosphate for most consumers.

2019Regulatory reviewEFSA ANS Panel opinion on phosphates

Ammonia release during baking

The ammonia released when ammonium phosphates decompose under heat largely volatilises off during baking. Residual ammonia in the finished product is typically very low. No toxicological concern has been identified at the levels that remain in baked foods.

Thermal decomposition of ammonium phosphates in baking conditions results in ammonia gas that mostly escapes into the atmosphere; residues in finished baked goods are well below any level of toxicological concern.

2013Regulatory reviewEFSA Scientific Opinion on ammonium phosphates (E 342)

Where it stands with the regulators

Not authorised as a food additive in Great Britain

Legal basis: Absent from Annex II of the assimilated Regulation (EC) No 1333/2008; no entry on the FSA's food additive authorisations register
Safe-intake limit (ADI): Not specified (acceptable daily intake not numerically set by EFSA, reflecting low concern at typical food use levels)

Who should be careful

People with chronic kidney disease are advised by nephrologists to limit all inorganic phosphate additives, since impaired kidneys struggle to excrete excess phosphate. Look for 'ammonium phosphates' or 'E342' on the label. Those on a medically prescribed low-phosphate diet should treat it the same as any other phosphate additive.

The honest read

Ammonium phosphates have been used in commercial baking for well over a century and their chemistry in food is thoroughly characterised. The main open question is not E342 itself but the cumulative load of phosphate additives across all processed foods eaten daily. EFSA flagged this collective exposure picture in 2019 and called for intake monitoring. For most people eating biscuits or bread in normal quantities, the phosphate from E342 is modest compared with phosphate naturally present in meat, dairy, and wholegrains. The kidney-disease association is real but rests on observational data about total phosphate burden, not on any study specifically implicating E342.

Common questions about ammonium phosphates

Is E342 banned in the UK?

E342 is not authorised as a food additive in Great Britain. It does not appear in Annex II of the assimilated Regulation (EC) No 1333/2008, and the FSA's food additive authorisations register holds no entry for it. The phosphates authorised for food use are E338 to E341, E343 and E450 to E452.

Do ammonium phosphates leave ammonia in my food?

Almost none. The ammonia produced when ammonium phosphates react during baking almost entirely escapes as gas in the oven. Finished biscuits and bread contain only trace residues.

What foods contain E342?

Mainly biscuits, crackers, wafers, and some breads. Diammonium phosphate (E342ii) is also added to wine and cider as a yeast nutrient during fermentation.