Review Article Benzene As a Chemical Hazard in Processed Foods

Hindawi Publishing Corporation International Journal of Food Science Volume 2015, Article ID 545640, 7 pages http://dx.doi.org/10.1155/2015/545640 Review Article Benzene as a Chemical Hazard in Processed Foods Vânia Paula Salviano dos Santos,1 Andréa Medeiros Salgado,1 Alexandre Guedes Torres,2 and Karen Signori Pereira3 1 Laboratorio´ de Sensores Biologicos,´ Escola de Qu´ımica, Universidade Federal do Rio de Janeiro, Avenida Horacio´ Macedo 2030, CT, Bloco E, Sala E-122, Ilha do Fundao,˜ 21941-598 Rio de Janeiro, RJ, Brazil 2Laboratorio´ de Bioqu´ımicaNutricionaledeAlimentos,InstitutodeQu´ımica, Universidade Federal do Rio de Janeiro, AvenidaAthosdaSilveiraRamos149,CT,BlocoA,Sala528A,IlhaFundao,˜ 21941-909 Rio de Janeiro, RJ, Brazil 3Laboratorio´ de Microbiologia de Alimentos, Escola de Qu´ımica, Universidade Federal do Rio de Janeiro, Avenida HoracioMacedo2030,CT,BlocoE,SalaE-104,IlhadoFund´ ao,˜ 21941-598 Rio de Janeiro, RJ, Brazil Correspondence should be addressed to Vaniaˆ Paula Salviano dos Santos; [email protected] Received 18 August 2014; Revised 13 January 2015; Accepted 21 January 2015 Academic Editor: Jessica L. Jones Copyright © 2015 Vaniaˆ Paula Salviano dos Santos et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. This paper presents a literature review on benzene in foods, including toxicological aspects, occurrence, formation mechanisms, and mitigation measures and analyzes data reporting benzene levels in foods. Benzene is recognized by the IARC (International Agency for Research on Cancer) as carcinogenic to humans, and its presence in foods has been attributed to various potential sources: packaging, storage environment, contaminated drinking water, cooking processes, irradiation processes, and degradation of food preservatives such as benzoates. Since there are no specific limits for benzene levels in beverages and food in general studies have adopted references for drinking water in a range from 1–10 ppb. The presence of benzene has been reported in various food/beverage substances with soft drinks often reported in the literature. Although the analyses reported low levels of benzene in most of the samples studied, some exceeded permissible limits. The available data on dietary exposure to benzene is minimal from the viewpoint of public health. Often benzene levels were low as to be considered negligible and not a consumer health risk, but there is still a need of more studies for a better understanding of their effects on human health through the ingestion of contaminated food. 1. Introduction of contaminated foods and water also play a role. Benzene can enter foods in many ways: use of contaminated raw materials Benzene (C6H6, CAS number 71-43-2) is an aromatic hydro- and packaging materials, storage in contaminated areas, carbon widely used as a solvent in chemical laboratories and and use of contaminated water for washing or preparing as an intermediate in the chemical industry for manufac- thefood.Itmayforminfoodbysomecookingprocesses, turing of polymers and other products [1]. It is a common thermal decomposition of food components, additives, food contaminant in the atmosphere. Roughly 99% of the benzene irradiation, and preservative decomposition such as benzoate present in the human body was inhaled. Benzene in air decomposition [5, 6]. Agricultural products may also be comes either from natural sources, such as forest fires and contaminated with benzene from emissions caused by fires volcanic activity, or from human activities, such as cigarette and the use of fossil fuel-burning equipment [7]. Finally, smoking and burning of fossil fuels [2]. Benzene is classi- benzene may form in some food additives, such as liquid fiedbytheInternationalAgencyforResearchonCancer smoke, during their manufacturing. Liquid smoke is made (IARC) as a Group 1 human carcinogen [3]. Nonsmokers from partial wood combustion [8]. inhale roughly 200–450 g of benzene a day, while smokers In 1993, Gardner and Lawrence [9]foundthatbenzene may inhale three times as much [4]. Most of the human canformwhenbenzoateisdecarboxylatedinthepresence exposure to benzene occurs by inhalation but consumption of ascorbic acid and transition metals such as Cu(II) and 2 International Journal of Food Science Fe(III) and can be accelerated by light and heat [10]. Benzoate ionizing radiation [17]. Not much information is available on and ascorbic acid are widely used as preservatives and smoking, except for a study that found benzene concentra- antioxidants, respectively, in nonalcoholic beverages but they tions of 21 and 121 parts per billion (ppb) in smoked meats may also occur naturally in foods [11]. [8, 18]. Transition metals such as the ones mentioned above may Benzene in foods may form when the amino acid catalyze the transfer of one electron from ascorbic acid to oxy- phenylalanine is broken down by ionizing radiation [19, 20]. gen, producing the anion superoxide, which then undergoes While studying the mechanism of benzene formation in spontaneous dismutation producing hydrogen peroxide. The carrot juice for children, Lachenmeier et al. found that some further reduction of hydrogen peroxide by ascorbic acid is substances, such as -carotene, phenylalanine, or terpenes, also catalyzed by those metals. This reduction may generate may decompose during processing to yield benzene [21]. hydroxyl radicals, which can decarboxylate benzoic acid and Six samples of beer have been contaminated with benzene form benzene [9]. through the use of contaminated carbon dioxide during Most studies indicate nonalcoholic beverages as the best carbonation [22]. candidates for benzene formation since ascorbic acid and sodium, potassium, or calcium benzoate are usually present 2.2. Reaction between Benzoic Acid or Benzoates and Ascorbic in their composition. Acid. Because of the growing demand for processed foods, Nutritive sweeteners such as sugar and high-fructose corn preservatives have been gaining importance in modern food syrup, ethylenediaminetetraacetic acid (EDTA), and sodium technology. Benzoic acid and its sodium and potassium salts hexametaphosphate may reduce or even inhibit benzene are among the most common preservatives used for inhibit- formation, increasing the susceptibility of diet and light ing microbial growth because of their cost-benefit ratios23 [ ]. nonalcoholic beverages to benzene formation [12, 13]. The Benzoates control the growth of some bacteria, filamentous ability of EDTA and sodium hexametaphosphate to chelate fungi, and yeasts, preventing product deterioration and the Cu(II) and Fe(III) ions may be reduced by competition, that growth of pathogenic species [24]. is, by adding calcium or other minerals to the food. Another Although undissolved benzoic acid is the most effective important factor is storage time: the formation of benzene is antimicrobial agent, benzoates are used more often because greater when foods are stored for long periods of time under of their greater solubility in water. Benzoic acid has low high temperatures [10, 11, 14]. solubility in normal temperatures [25]. A solution of benzoic In 2006, the American Beverage Association [12]pub- acid contains dissolved and undissolved molecules in equi- lished some guidelines to help beverage manufacturers to librium. As the pH decreases, the equilibrium shifts towards reduce or inhibit the formation of benzene in their prod- undissolved benzoic acid [26]. ucts. The most important guidelines involve replacing ascor- Sodium, potassium, and calcium benzoates and ascorbic bic acid by another antioxidant, adding EDTA or sodium acid may occur naturally in foods or be added as food polyphosphates to chelate the metalic ions that catalyze additives. Ascorbic acid usually occurs naturally in some hydroxyl radical formation, and reviewing the storage con- fruit juices, such as orange, lime, and acerola, among others, ditions and shelf life to minimize product exposure to high and may also be added as an antioxidant or nutrient. Some temperatures and ultraviolet (UV) light [10]. benzoates/benzoic acids are present in some fruits and may There are no legal limits for benzene in foods or bever- be added as preservatives, especially in acidic foods with a ages. The limit established for potable water is used as ref- pH < 4.5, which is usually the case of nonalcoholic beverages erence: 10 ppb established by the World Health Organization [26]. (WHO), 5 ppb by the United States (USA) Environmental Transition metals, such as Cu(II) and Fe(III), may catalyze Protection Agency, and 1 ppb by the European Council [11, the transfer of one electron from ascorbic acid to oxygen, 15]. producing the radical superoxide, which then undergoes In 2011, the Brazilian Federal Public Ministry (MPF) spontaneous dismutation to form hydrogen peroxide. Hydro- signed a conduct adjustment term (TAC) with three soft gen peroxide is further reduced, a reaction also catalyzed by drink manufacturers (Coca-Cola Industrias´ Ltda., Compan- those metal ions, and may generate hydroxyl radicals [27]. hia de Bebidas das Americas´ (AMBEV), and Primo Schincar- In 1965, Matthews and Sangster [28] found that irra- iol Industria´ de Cervejas e Refrigerantes Ltda.) establishing a diation of an aqueous solution of sodium benzoate causes maximum acceptable benzene content of 5 ppb [16]. hydroxyl radicals to attack benzoate ions forming unstable

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