As per information from”The Government of the Hong Kong Special Administrative Region”, Sources: From World Health Organization and others, Formaldehyde can be found naturally in food up to the levels of 300 to 400 mg/kg, including fruits and vegetables (e.g. pear, apple, green onion), meats, fish (e.g., Bombay-duck, cod fish), crustacean and dried mushroom, etc.

Examples of Foods Known to Contain Naturally Occurring Formaldehyde:

Food type                                              Level (mg/kg)

Apple                                                       6.3 – 22.3 

Apricot                                                     9.5

Banana                                                      16.3

Bulb vegetables (e.g. onion)           11.0

Cabbage                                                   5.3

Carrot                                                       6.7 – 10

Cauliflower                                             26.9

Cucumber                                               2.3 – 3.7

Grape                                                       22.4

Pear                                                         38.7 – 60

Plum                                                        11.2

Potato                                                    19.5

Tomato                                                  5.7 – 13.3

Water-melon                                       9.2

For more information please visit

http://www.cfs.gov.hk/english/whatsnew/whatsnew_fa/files/formaldehyde.pdf