Food Safety Focus (57th Issue, April 2011) – Food Safety Platform

Abuse of Certain Chemicals as Food Additives

Reported by Ms. Melva CHEN, Scientific Officer,
Risk Assessment Section, Centre for Food Safety

Mix and match clothing at one's pleasure may bring us surprises. But when talking about food, wrong matching may give you a scare. In fact, some chemicals and foods should never be mixed together for safety reasons.

What is a Food Additive?

A food additive is any natural or synthetic substance intentionally added to food in the processing, packing, transport or storage of food for a technological purpose (e.g. inhibition of microbial growth, extension of the shelf-life, enhancement of flavour and odour). Common food additives include preservatives, antioxidants, sweeteners, colouring matters, flavour enhancers, thickeners and emulsifiers. Food additives do not include nutrients such as vitamins and minerals used for enriching food, or herbs and spices when used as seasonings.

Food Safety Always Come First

Some chemicals have been abused as food additives. Examples are the use of Sudan dyes in curry power, red 2G in Chinese sausage , orange II in BBQ pork and Rhodamine B in preserved olive as colouring matters and boric acid in shrimp, salicylic acid in fish balls and formaldehyde in noodlefish as preservatives and texture modifiers. The technical functions of these chemicals alone cannot justify their use in foods because a chemical has to undergo thorough safety evaluation by international food safety authorities before it can be approved for use as a food additive. Public health is of the utmost importance. Chemicals that have potential to cause adverse health effects to consumers (e.g. toxic to organs such as stomach, liver, kidney; causing cancer or inducing DNA damage) for their intended use in food or have inadequate data for safety evaluation will not be permitted for use as food additives.

A Short Cut But A Wrong Path

The above mentioned chemicals in general share some common characteristics, namely inexpensive, user-friendly and effective. The abuse of these chemicals may be considered as a short-cut method to food production by some irresponsible manufacturers. Unfortunately, a short cut often leads to a wrong path. For example, there are several ways to produce fish balls with desirable elastic mouth-feel (so called "springy fish balls"). Some manufacturers may follow the traditional method by selecting high quality fish with the minimal use of binders such as starch and make fish balls by hand-kneading. Others may apply modern technology and develop optimal recipes and processing conditions (such as time and temperature for curing (gel-forming) and extrusion) for their fish balls. An illegal short cut, however, is by adding boric acid or salicylic acid into the fish paste. These chemicals are not only abused as preservatives in fish balls but also as texture modifiers by increasing the gel strength of the fish paste. However, both boric and salicylic acid can cause gastric irritation and long-term, excessive intake may result in kidney damage so they are unsuitable as food additives.

Another malpractice is the abuse of non-permitted colouring matters. For example, to give a natural chili-like red colour to a seasoning mix, one can use permitted colouring matters annatto extract or paprika oleoresin. However, these colouring matters are relatively expensive and volatile, therefore some food processing techniques need to be followed in using these additives. Usually they have to be precisely measured and be blended with salt before adding to the seasoning for consistency in colour intensity and for safe and easy handling. On the other hand, if Sudan dyes are used, no special handling would be needed. However, Sudan dyes should not be used in food because of their cancer causing potential.

Combat the Abuse of Non–permitted Food Additives

In Hong Kong, we have routine and targeted food surveillance programmes in place to control the abuse of non-permitted food additives. To ensure food safety and reduce the abuse of non-permitted food additives, food trade plays a paramount role in ensuring food safety of their products. Food trade should conform to the regulations and be cautious when sourcing food ingredients and additives from suppliers.