April 1, 2017

The Place of Benzoic Acid in Food Preservation

The Nigerian social media space have been awash in the last few weeks with speculations, innuendos, insinuations or otherwise of the toxicity and carcinogenicity of carbonated beverages in the Nigerian market especially those produced by Nigerian Bottling Company (NBC). While some claim it kills out rightly when taken with Ascorbic Acid (Vitamin C), others put it as definitive cause of cancer.

The most worrying aspect of the whole discuss is that most of the information were based on hearsay. Only very few did in-depth literature review to decipher the true position of things as it relates to the controversy. A good number of them never cared to confirm the authenticity or otherwise of what they heard before spreading the news.

For some time now I made a deliberate decision to ignore posts on the social media especially if that information is not from a scientific source. I made this decision based on the fact that I have been personally abused thoroughly because I tried to correct some wrong postings. Because of the above I deliberately did not subscribe to WhatsApp and don’t have a WhatsApp account. So I completely missed out on the NBC and Benzoic acid brouhaha until much later.

My attention was draw to this present controversy when I was confronted by a friend who walked into my office and met me sipping from my favourite Coca-Cola. “Doc do you want to kill yourself, have you not heard that Coke products kill? Their product was even turned back by United Kingdom authorities. It is there on the net”. He went further to show me a number of posts on his WhatsApp page on his phone. Of course majority of them were illogical and incoherent.

As a Medical doctor and a research fellow at the apex medical research institute in the country, the Nigerian Institute of Medical Research, Lagos, I reasoned that the public will benefit from an objective analysis of the issues involved based on available scientific and regulatory evidence. Providing correct and accurate information requires in depth literature review. In this write up I have provided information I hope will assiste Nigerians to make a balanced judgment.

What is benzoic acid?

Benzoic acid is a colourless crystalline solid. It is the simplest aromatic carboxylic acid. It occurs naturally free and bound as benzoic acid esters in many animal and plant species. Significant amounts have been found in some fruits – especially berries – as well as in yogurt, certain spices and honey. Most berries contain around 0. 05%. Benzoic acid is also rapidly absorbed from the gastrointestinal tract of mammals and conjugated with glycine in the liver. The resulting hippuric acid is excreted in the urine rapidly (75% to 100% of the dose is excreted within 6 hours; the remaining dose is excreted within 2 to 3 days).

Benzoic acid as food preservative

Benzoic acid is most effective as a food preservative in acidic food. It seems to harm microbes by preventing them from fermenting glucose, but it may have other effects on the microbes as well. Artificial benzoic acid is added to food and to products such as toothpastes, shampoos, carbonated drink, fruit juices, cosmetics and medicines in order to prevent microbial growth.

Regulatory requirements

The legal limits for benzoic acid as a preservative vary from country to country, and depend on environmental and weather conditions. For carbonated drinks the recommendations are;

  1. Codex Alimentarius Commission. The Codex Alimentarius Commission is a joint intergovernmental body of the Food and Agriculture Organization of the United Nations (FAO) and WHO with 186 Member States and one Member Organization (EU). Codex has worked since 1963 to create harmonized international food standards to protect the health of consumers and ensure fair trade practices. Codex standards ensure that food is safe and can be traded. The 188 Codex members have negotiated science based recommendations in all areas related to food safety and quality: food hygiene; maximum limits for food additives; residues of pesticides and veterinary drugs; and maximum limits and codes for the prevention of chemical and microbiological contamination.
  2. The committee in 2016 adopted a maximum level of 250mg/kg for preservatives in water-based flavoured drinks, including “sport,” “energy,” or “electrolyte” drinks and particulated drinks. Before 2016 a high limit of 600mg/kg was operational.
  3. Standard organisation of Nigeria (SON). SON was established by an Enabling Act Number 56 of December 1971 – the Standards Organisation of Nigeria cap 412 of the laws of Federal Republic of Nigeria, with a commencement date of 1 January 1970, when the Organisation started to function.
  4. The Act has three amendments: Act Number 20 of 1976, Act Number 32 of 1984 and Act Number 18 of 1990. The mandate of the Organisation includes preparation of Standards relating products, measurements, materials, processes and services amongst others and their promotion at National, Regional and International levels; certification of products, assistance in the production of quality goods and services; improvement of measurement accuracies and circulation of information relating to standards. SON has two legal limits for benzoic acid as food preservative.
  5. If product contains Vitamin C (Ascorbic acid): less than 250 mg/kg.
  6. No Vitamin C (Ascorbic acid): Less than 300 mg/kg.

In temperate regions lower levels of less than 150mg/kg is the legal limit.

Is benzoic acid safe?

Benzoic acid occurs naturally in various berries notably cranberries, cinnamon, plums, currants, cloves etc. It has long been used to inhibit microbial growth in many products including non-alcoholic beverages, jams and emulsified sauces. The salt of the benzoate is more stable than the acid form and more soluble in water making the benzoates a favourable choice for the soft drinks industry.

Sodium Benzoate has been in use for more than 100 years and is widely used by the food and beverage industries to maintain quality and taste. It is approved for use in soft drinks by the European Union as well as other international regulatory bodies including the United States, Australia, Canada and Japan.

Benzoic acid is very effective against moulds, yeasts and bacteria. It is particularly well suited for use in soft drinks, such as carbonated, still and juice beverages because it works best between pH levels of 2 – 4. The composition of the drink therefore has an effect on its efficiency and suitability for use.

When ascorbic acid (vitamin C) is present as an ingredient in beverages along with sodium benzoate, benzene formation may occur under certain conditions. Formation of benzene is exacerbated in beverages if they are stored for extended periods at elevated temperatures.

Although the levels and frequency at which such benzene formation has occurred in the past, it has not been considered to pose a public health risk, the soft drinks industry has developed methods to prevent or minimize its occurrence. In recent years the use of benzoates has been reduced because of new processing techniques, but it is still necessary to use these preservatives in some beverages to maintain their quality. Hence the legal limits set by various regulatory agencies including SON.

Like all additives, preservatives have to be approved for use in drinks and foods before they can be used. Expert organisations such as the Scientific Committee for Food, the European Food Safety Authority and the Joint FAO/WHO Food Additives Committee have examined the safety of each preservative and made recommendations on their use including maximum levels. Such recommendations were taken up by governments both nationally and at the European level so that food and drinks can be preserved effectively whilst ensuring the food is safe to consume.

Benzoic acid level less than 200mg/kg is in carbonated drinks produced by NBC, which is below the regulatory limits, benzoic acid is safe. Available scientific evidence shows that at this level the carbonated drinks are safe for human consumption.

Issues surrounding the Nigerian benzoic acid controversy.

What are the issues around the present controversy? Is Benzoic acid a safe food preservative? Is Nigerian bottling company guilty from the scientific and regulatory stand point? Are they legally liable? For the last question, I am not qualified to attempt to answer and will not. For others I will address based on available scientific and regulatory evidence.

  1. According to Codex Alimentarius Commission, SON, Nigeria, EU commission and US Food and drug agency benzoic acid is a safe food preservative. By exception NBC products containing benzoic acid are food preservative.
  2. Did NBC contravene the regulatory requirements? NBC products contain benzoic acid levels below 200 mg/kg which is below the regulatory limits recommended by the various regulatory agencies and committees, including Nigerian’s SON. No regulatory requirement is breached by NBC.

iii. Why was the product turned back from United Kingdom (U.K.) or rejected? As stated earlier, globally there are different regulatory levels for different products in different countries depending on several factors and conditions. In this case, U.K. is a temperate climate and the weather doesn’t support microorganism growth. The recommended benzoic acid limits level is set at below 150 mg/kg. Nigeria is a tropical country and the weather supports microbial proliferation and thus requires higher benzoic acid limit level, hence the higher 250 or 300 mg/kg limit set by SON. I suspect that NBC recognising the literacy level in the country decided to use a single lower limit that met both standards and at the same time avoid confusion.

  1. The main issue in this controversy that all well-meaning Nigerians should condemn is the export of products meant for Nigerian market to U.K without due diligence, which resulted in the embarrassment. It can be inferred that the company did not obtain the necessary approvals from relevant agencies, which are in the position to assist and ensure that all necessary trade/industry requirements were fulfilled. It is hoped that while the controversy is going on, the appropriate agencies are doing the needful to ensure that we are spared this unnecessary embarrassment in future. For those planning to export products out of Nigeria in future, please do ensure that appropriate regulatory approval is obtained for export. It is NBC product today, tomorrow it could be another.
  2. Rejection of a product is not always because of poor quality, often it maybe due to non-conformity with regulatory requirements. Reasons for having “America or Europe specification products” etc. A typical example is the requirement for cars to be used in Sweden and other Scandinavian countries to have head lights that come on automatically when the switch of the ignition key is turned on. Any car sent to any of these countries without this specification will be sent back irrespective of its quality, because it violates a strict weather induced requirement. In Scandinavian countries weather can suddenly change in a matter of seconds and to avoid accidents on their roads, the regulation was put in place.
  3. Such regulation is not necessary in Nigeria because of our ever beautiful weather.
  4. As a scientist, I was quite curious and alarmed at the media reports that the UK agencies described the consignment of Fanta and Sprite as “unfit for human consumption”, and I think this purported verdict on the products was what elevated the panic and angst among Nigerians. My concern was, would a UK agency indeed describe a product with the stated levels of benzoic acid in such language?
  5. I was lucky to receive one of the numerous alarming social media messages to which was attached the 23-page court ruling. A verbatim quote from a letter by Gareth Hollingsworth, the StockPort Metropolitan Borough Council Trading Standards Officer to the claimant reads “fanta cannot be supplied or exposed to sale because it is non-compliant with EU legislation” The officer went further to state that “I would recommend that any future imports are subjected to analysis before you import a vast quantity to ensure that products are complaint with EU legislation. It appears that different countries have different limits for additives”. It is thus surprising how “non-compliant with EU legislation” became “unfit for human consumption”

vii. Another lesson from this fiasco is that government agencies need to learn to work together and not compete with each other. There has been this rivalry between NAFDAC and SON which I guess played out in this controversy.

Lessons have been learnt from this controversy and I do hope that we all must learn to research before making comments on issues that are outside our core competencies. We can only engage in meaningful discussion when we base our arguments on hard science not emotions. Based on hard science, I am convinced that NBC has not violated any regulation and their products are safe for human consumption.

Finally, the time is now for the regulatory agencies to turn their search light on all companies to ensure they comply with quality standards. We as researchers are ready to evaluate the products in the Nigerian market and invite philanthropic Nigerians to support us in this quest. Together we shall make Nigeria great again.


Dr. Oliver C. Ezechi, is the Deputy Director Research, Nigerian Institute of Medical Research, Yaba Lagos