Can Our Food be Completely Safe?

Peter Berry Ottaway

Berry Ottaway & Associates

24 June 2005

The speaker is a food scientist & technologist. After working in Zambia for the WHO, he formed a scientific & technical consultancy specialising in food science, technology, nutrition & food law. He has played an active role in the development of EU legislation in this area. Chairman of the Institute of Food Science & Technology’s Technical & Legislative Committee, he is the author of books & papers on various aspects of nutrition, and has academic appointments in three universities, both in the UK & USA.

Over the past two decades we have been evolving into a risk-averse society with evangelical zeal. Unfortunately, as is constantly demonstrated, life can never be without risk and it is unlikely that our food, one of the basic needs, can ever be completely free of risk.

The last 20 years have seen a number of food scares in the UK, including Spongiform Bovine Encephalitis (BSE) in cattle, listeria in cheese, salmonella in eggs, cryptosporidium in water, mercury, dioxins and polychlorinated biphenyls in fish and botulism in yoghurt.

Consumer research has shown that the public perception of food safety is often in contrast to the facts. For example, food additives come well up the list of general concerns about food safety, whereas microbiological contamination of food comes near the bottom. In reality, bacterial contamination of food is a daily risk to human health and life. With our current state of knowledge and the availability of refrigeration and freezing in stores, restaurants and the home, Britain should not have the very high incidence of microbiologically related food poisoning reported each year. Most of these cases can be attributed to lack of training and control, the human element.

The Public Health Laboratory has monitored the sources of food poisoning in the UK and 53% of the cases were from non-institutional catering premises, such as restaurants, cafés, hotels and public houses (see diagram).

Institutional catering such as that in hospitals, care homes and schools, contributes a further 21%. In our Western society microbiological food poisoning is controllable by simple, inexpensive procedures, yet the annual figures show an increase rather than a decrease in incidence.

‘If it is natural, it must be safe’ is a mantra. This is a fallacy and even some of the staple foods can contain toxic components. For example, potatoes that have been exposed to light during storage and form green patches can contain a poisonous substance known as solanine, of particular concern to pregnant women. Red kidney beans that are now commonly found in salads are poisonous unless cooked sufficiently to destroy a naturally occurring toxin. Cassava, a staple carbohydrate source in West Africa, needs a process of soaking and fermentation to render it safe. Untreated cassava is associated with two diseases, amblyopia (a form of blindness) and atoxic neuropathy (a degenerative disease).

In addition to toxins in foods that affect the population in general, there are many food intolerances and allergies that affect sub-groups of the population. Lactose intolerance (an adverse reaction to milk sugar) has a genetic basis and is found in parts of West Africa and also in the southern states of the USA, the latter as a consequence of the slave trade. Proteins in a wide range of foods such as milk, soya, fish, shellfish and nuts can cause severe allergenic reactions in sensitive individuals.

Food is also affected by a number of environmental contaminants. Some, such as dioxins and polycyclic aromatic hydrocarbons, are released into the atmosphere from combustion processes. Others, such as pesticides, poly-chlorinated biphenyls and brominated compounds are man-made.

Toxic heavy metals such as lead, cadmium and arsenic enter the food chain through plants grown in soils in which these elements are present. During their growth and post-harvest storage, many food crops are susceptible to contamination from mycotoxins resulting from mould growth.

A disturbing development over the past five years is the discovery that potentially carcinogenic substances can be formed during the processing of a number of common foods. The first to come to light was the choropropanol 3-MCPD, which has been found to be produced by a reaction between a source of chlorine and a lipid in the presence of heat. It was first found in hydrolysed vegetable protein, a component of soy sauce.

More recently, the formation of acrylamide in foods was discovered by accident. Acrylamide, an industrial chemical and potential carcinogen, has been found in a number of fried and baked foods. Recent research indicates that it could be formed in the food by the reaction between a specific amino acid and a reducing sugar at relatively high temperatures.

An aspect of food safety that is more difficult to identify with normal quality control procedures is the deliberate adulteration of food. Adulteration is mainly carried out to increase profits on high value foods and ingredients by adding cheaper components. Some years ago a considerable amount of ‘fresh’ orange juice was found to be adulterated.

In a few cases adulteration has been used to improve the visual appearance of a food. This had serious consequences for the British food industry in early 2005 when it was discovered that a consignment of chilli powder from India had been dusted with the illegal red colour Sudan I to improve the visual appearance of the spice.

A very small proportion of the cases of adulteration can be attributed to disgruntled employees.

The problems of adulteration of food go back to early times and the first English food laws were introduced by Henry II to prevent the addition of chalk to flour. Since the mid-20th century the problem has become more sophisticated and much more difficult to detect.

Despite these challenges the primary responsibility of professional food scientists and technologists is to ensure that food is as safe as possible within the current state of scientific knowledge, and that all the requirements of food legislation are met. Thus, food scientists and technologists have a legal and moral responsibility to ensure that food is as safe as reasonably possible from ‘farm to fork’. This requires a detailed knowledge of all the factors that can affect the safety of the foods for which they are responsible.

Within the UK well over 90% of the food legislation is directly derived from EU food law, which has the primary objectives of ensuring:

A high level of protection of human life and health

The protection of consumers’ interests

Fair practices in food trade.

 

Specifically, the law requires that food must not be placed on the market if it is unsafe either by being injurious to health or by being unfit for human consumption. To this end there is a large number of controls on foods and ingredients.

 

No food additives or food contact packaging materials can be used unless they are permitted in law. Since 1997 all new foods, ingredients and certain new processes, which had not been consumed to a significant degree in one or more EU countries before 1997, must be subjected to an official safety review before being placed on the market. This also applies to fruits and vegetables consumed in other parts of the world but with no history of consumption in the EU.

The safety assessments referred to above are expected to cover short-term toxicity (poisoning), and long-term toxicity including the potential to induce cancers or have a deleterious effect on the foetus. The third area of concern is the potential to produce allergic reactions in susceptible individuals.

There are also very strict laws in force covering a wide range of chemical contaminants, both man-made and environmental. The use of foods and ingredients derived from genetically modified organisms is also governed by stringent legislation.

In order to ensure that all the above factors have been taken into consideration and that food is produced under the best possible hygienic conditions, all responsible producers apply the principles of Good Manufacturing Practice (GMP).

GMP consists of a series of guidelines aimed at ensuring that food and drink products are consistently manufactured to a quality appropriate to their intended use. These guidelines cover all aspects of food production, distribution and storage, and provide details of how the appropriate controls should be set up and maintained.

A key part of GMP that is due to become law on 1st January 2006 is ‘Hazard Analysis and Critical Control Point’ with the acronym HACCP. HACCP requires a detailed analysis of all the potential hazards in a food business (e.g. microbiological, chemical and foreign matter contamination) and the identification of the points in the operations where such hazards could occur. A decision then has to be made as to which of these points are critical to the safety and quality of the food (critical control points). Procedures are then put in place to ensure that the potential hazards are prevented at the critical points. When operated correctly HACCP can make a very significant contribution to food safety.

However, despite all the effort and controls, there will constantly be new challenges in the form of new strains of bacteria and new potentially dangerous substances.

Whilst food scientists and technologists constantly strive to make the food supply as safe as reasonaly possible, the

question needs to be asked ‘can our food ever be absolutely safe?’

Recommended Reading.

I Shaw. Is it safe to eat? (Springer-Verlag, Germany)

Food and Drink Good Manufacturing Practice: a Guide to its Responsible Management 4th edn.’(The Institute of Food Science & Technology, London W6 7NJ)

D Watson (ed.) Food Chemical Safety. vol.1. ‘Contaminants’, vol. 2. ‘Additives.’ (Woodhead Publishing, Cambridge, UK).