Yes, GDL has been approved as a safe preservative by U.S. Food and Drug Administration (FDA), European Food Safety Authority (EFSA), as well as Joint FAO/WHO Expert Committee on Food Additives (JECFA).

FDA
FDA has affirmed glucono delta lactone is generally recognized as safe (GRAS) as a direct human food ingredient. And it can be used as a curing and pickling agent, leavening agent, pH control agent; and sequestrant in food with no limitation other than current good manufacturing practice. (3)

EFSA
Glucono-delta-lactone (E575) is listed in Commission Regulation (EU) No 231/2012 as an authorised food additive and categorized in “Additives other than colours and sweeteners” (4).

Approved uses and usage
GDL is classified in class I with the use level “quantum satis”, which means there is no specific limit in its uses.

The following food may contain it (5):

Mozzarella
Ripened cheese (products), whey cheese
Canned or bottled fruit and vegetables
Fresh (pre-cooked) pasta
Biscuits and rusks for infants and young children
UK Food Standards Agency
Categorized in “Others” (6)

Food Standards Australia New Zealand

It is an approved ingredient in Australia and New Zealand with the code number 575. (7)

JECFA
Function Class: food additives, acidity regulator, raising agent, sequestrant. (8)

Acceptable daily intake: ADI “not specific” set in 1998, also for sodium, calcium, magnesium, potassium salts of gluconate. (9)

http://www.chinafooding.com/Glucono_Delta_Lactone