Download Toxic Food Preservatives : Sulfur Dioxide and Sulfites

Food Additive Unit: Mahanum, Bhuvaneswary, Analiza and Junainah
Toxic Food Preservatives : Sulfur Dioxide and Sulfites
The New Straits Times, July 7, 2001 Penang (Malaysia) –
The Consumers Association of Penang (CAP) says Thai-imported longans sold in the State were
found to contain 113.6 ppm (parts per million) of sulfur dioxide and are unsafe for human
consumption. Sulfur Dioxide, used as a food preservative, is toxic and could cause skin disorders
including swelling, general weakness and tightening of the chest to those who are sensitive to the
substance.
Are additives safe?
The vast majority of additives and preservatives appear to be safe. They have been tested by
many laboratories throughout the world before being used in foods. However, individuals may be
"sensitive" to various additives and preservatives. An example of additive to be discussed here is
sulfur dioxide. Although very limited cases reported on sulfur dioxide toxication to human health, it
is important to educate the public about the use of sulfur dioxide in foods.
According to the Food Regulations 1985 under Regulation 20(Sixth Schedule), sulfur
dioxide maybe added to foods in proportions not greater than the maximum permitted
proportions.
What is sulfur dioxide?
Sulfur dioxide occurs naturally in volcanic gases, in some dissolved waters of warm springs, and
is a result of coal, fuel, and gas combustion. . It is produced industrially as a bleach alternative, a
reducing agent, and for sulfites (preservation).
What are the uses of sulfur dioxide in foods?
Sulfur dioxide is used as a preservative because it works as an antimicrobial preventing the
growth of bacteria, mold, and fungus; an antioxidant preventing rancidity; and as a chemical that
attacks enzymes that cause discoloration, ripening, and rotting, usually in fruits after harvesting. It
also helps food products maintain an appealing visual appearance. Sulfur dioxide may be labelled
as sodium metabisulphite, potassium metabisulphite, sodium or potassium bisulphite or sulphite.
Types of foods added with sulfur dioxide
Sulfites are widely used in the preservation of fruits and vegetables and are added to many
processed snacks including cookies, pickles, soft drinks, meat, cereal bars, yogurt, ice cream,
candy, frozen french fries, bread, margarine, and gluten-free flours. It is also used in the process
of making wine, and is found in ingredients like vinegar, corn syrup, corn starch, maltodextrin,
dressings, and glucose syrup.
Effects of sulfur dioxide consumption to human health
Whilst harmless to healthy persons when used in recommended concentrations, it can induce
asthma when inhaled or ingested. According to (World Health Organization, 1999), sulfur dioxide
when introduced, it inhibits specific nerve signals, restricts lung performance and is a direct
allergen where over 65% asthmatic children are sensitive to sulfur dioxide.
What can I do to prevent exposure to sulfur dioxide in foods?
Read labels on foods very carefully and avoid all food that contains the preservative or additive.
Eat more raw and living foods, get rid of processed foods in the diet, as well as buy dried nuts
and snack fruits from companies known for being preservative-free and supplies healthier snack
alternatives like dried fruit, nuts and seeds, fruit juices, and gluten-free products.
Analysis of Sulfur Dioxide at Makmal Kesihatan Awam Ipoh
Sulfur dioxide is analyzed using test method E04-009 of NPHL: The Determination of Sulfur
Dioxide in Food by Titration and limit of quantitation (LOQ) of this method is 5mg/kg. This method
was accredited with MS ISO/IEC 17025 in 2010 and applicable for determination of sulphites
calculated as sulfur dioxide in foods.
Table below shows total received samples for analysis of sulfur dioxide by food group and numbers of contravention from year 2008 until
September 2011 at Food Additive Unit, Makmal Kesihatan Awam Ipoh
Sweetening substance
Meat & Meat Product
Milk & Milk Product
Vinegar, Sauce, Chutney &
Pickle
Edibel Oil
Edible Fat &
Tea, Coffee & Chicory
Soft Drink
NS =
3
Confection
NS =
1
Salt & Spice
42
Cereal, Cereal Product
Fruit & Fruit Product
23
Vegetable & Vegetable
Product
Fish & Fish Product
TOTAL SAMPLES BY FOOD GROUP
Nut & Nut Product
YEAR
TOTAL
2008
7
0
18
1
12
4
12
52
2009
1
26
2010
41
48
95
JanuarySeptember
2011
NS=
1
NS =
2
7
1
NS =
1
7
1
1
12
2
3
0
117
12
7
0
2
6
1
0
1
126
6
1
0
0
0
0
0
0
122
0
0
0
0
0
0
0
156
5
3
3
15
30
0
3
9
1
NS =
2
NOTE: NS = Not Satisfactory; contravened to Food Regulation 1985
Description of contravention by food group
Fish and Fish Product: Crispy Chip
Fruit and Fruit Product: Durian, Longan, Canned Lychee and Frozen Durian
Nut and Nut Product: UHT Coconut milk
Confection: Biscuit