Yes, it has been approved safe by the U.S. Food and Drug Administration (FDA) and European Food Safety Authority (EFSA), as well as the Joint FAO/WHO Expert Committee on Food Additives (JECFA).
FDA
Sodium citrate is generally recognized as safe (GRAS) when used in food with no limitation other than current good manufacturing practice. (6)
It can be used in following products (7):
Milk and cream
Cheeses and related cheese products
Artificial sweet fruit jelly, jam, and preserves
EFSA
Monosodium citrate E331(i), disodium citrate E331(ii) and trisodium citrate E331(iii) are listed in Commission Regulation (EU) No 231/2012 as an authorised food additive and categorized in “ additives other than colours and sweeteners” (8).
Approved uses
Sodium citrates are classified into “Group I” with the maximum use levels “quantum satis”, and also listed in its separate uses. The following food may contain it (9):
UHT goat milk, dehydrated milk
Edible caseinates
Cheese
Frozen fruit and vegetables
Canned or bottled fruit and vegetables
Jam, jellies and marmalades
Meat preparations, unprocessed fish
Table-top sweeteners in liquid, powder or tablet form
Infant formulae
Processed cereal-based foods and baby foods
UK Food Standards Agency
Categorized in “Others” (10)
Food Standards Australia New Zealand
It is approved ingredient in Australia and New Zealand with the code number 331. (11)
JECFA
Trisodium citrate
Function Class: food additives, acidity regulator, sequestrant, stabilizer. (12)
Acceptable daily intake: ADI “not limited” set in 1973. (13)
Sodium dihydrogen citrate
Function Class: food additives, acidity regulator, sequestrant. (14)
Acceptable daily intake: ADI “not limited” set in 1979. (15)
http://www.chinafooding.com/Sodium_citrates