Profiling, distribution and levels of carcinogenic polycyclic aromatic hydrocarbons in traditional smoked plant and animal foods

Highlights

• For the first time traditional smoking products in Spain (bread and paprika) were investigated.

• Low molecular weight compounds (F and P) represented the major contribution to total PAHs.

• PAH4 could be used as the best indicator of the occurrence of PAHs in the traditional products.

• Bread (3.4 μg/kg)<<cheese (88 μg/kg)<<sausages (1779 μg/kg)<<paprika (9937 μg/kg).

• Paprika is a condiment used in small quantities and does not represent a risk for consumers.

Abstract

The purpose of this study was to evaluate the concentration of polycyclic aromatic hydrocarbons (PAH8 plus fluoranthene and pyrene) in “Pan de Cea” bread, “Pimentón de La Vera” paprika, “San Simón da Costa”, “Idiazábal” and “Humus” cheeses, and “Chorizo” garlic pork sausage. Results obtained showed that harmless low molecular weight compounds (Fluoranthene and Pyrene) represented the major contribution to the total PAHs. The most important PAHs according to the levels found were those in the 4 PAHs group (the rest of PAHs to add a total of 8 were contributing at very low levels). PAH4 and PAH8 levels showed percentages ranging from 6.0 to 7.0 % in bread, 16–17 % in paprika, 23–28 % in cheese and 20–24 % in meat sausages, respectively. B(a)P did not exceed the imposed limits in the EU. Bread showed the lower PAH concentration (3.4 μg/kg) followed by cheese (88 μg/kg), smoked sausage (1779 μg/kg) and paprika (9937 μg/kg). “Pimentón de la Vera” paprika is a condiment consumed in small quantities. The PAH profile had in common the decrease in PAH content as their molecular weight increased. These results showed that the contamination detected in “Pan de Cea” bread samples was very low, so that the consumption of this product does not pose a health risk. In cheese samples, the PAH contamination was detected meanly in rind, that accounted around the 100% of the total contamination. In meat sausages samples, the 90% of the total PAHs determined were accumulated in the casing. Considering the edible part, the PAH4 and B(a)P mean contents were below the limit established. Although, the highest PAH levels were detected in “Pimentón de la Vera” paprika, it should be pointed out that this product is a condiment consumed in small quantities and not in an everyday basis, it does not represent a risk for consumers. In cheese and meat sausage, according our estimates, the removal of the external part can be considered a good consumer practices to reduce the ingestion of PAHs.

Introduction

Originally the purpose of smoking was to preserve the food. Nowadays smoking is primarily used to achieve the characteristic taste and appearance of smoked food and to a minor degree to obtain preservation. The traditional smoking process can be conducted in several ways, both from an organoleptic point of view and in the light of health aspects (COE, 1992). Some of the constituents in the smoke and in the smoke condensates may give rise to health problems e.g. the polycyclic aromatic hydrocarbons (PAHs). As it is well known, they are a group of chemical compounds that are formed during the incomplete combustion or pyrolysis of organic matter by a series of complex chemical reactions (Yebra-Pimentel, Fernández-González, Martínez Carballo, & Simal-Gándara, 2012). They accumulate on the surface to migrate after into the smoked products.

The European Food Safety Agency (EFSA) in an opinion article released in 2008, pointed that the carcinogenicity of PAHs through oral administration is the most relevant (EFSA, 2008). In particular, benzo(a)pyrene (B(a)P) has been reported to produce tumours of the gastrointestinal tract, liver, lungs and mammary glands of mice and rats. According to the Commission Regulation No 1881/2006 (EC, 2006a) B(a)P could be used as marker for the occurrence of PAHs in different types of food. Since September 2012 a new Regulation that modified the previous legislation (EC, 2006a) is applicable for these compounds in foodstuffs (EC, 2011) and establishes the four PAHs (PAH4): B(a)P, Chr, benzo(b)fluoranthene (B(b)FA) and benzo(a)anthracene (B(a)A) as the most suitable indicators of PAH in food. EFSA Panel suggested using the PAH4 marker as better indicator of the occurrence of PAHs in food than a benzo(a)pyrene (EFSA, 2008).

In the traditional smoking process, a fire is make using dried wood. The kind of wood used depends on tradition and normally it will differ from country to country. This variable, as well as, moisture content, oxygen availability and combustion temperature will contribute to PAH contamination. Although, It is probable that PAHs will be accumulated mainly on the products surface, some diffusion could take place to inner layers (Simko, 2005), where water activity and fat content have a determinant role in the diffusion process (Martorell et al., 2010). On the other hand, the presence of barriers such as the casing (in meat sausage) or rind (in cheese) are especially effective as barrier for soot (with plenty of PAHs) and can interfere with PAHs migration into products internal layers (García-Falcón and Simal-Gándara, 2005, Guillén and Sopelana, 2004).

To our knowledge, the evaluation of PAH levels in the typical Spanish bread (“Pan de Cea”) and paprika (“Pimentón de la Vera”) is presented for the first time in the present study. Moreover, the PAH levels in other smoked traditional foods were also considered as the most typical from Northwest Spain such as: garlic pork sausage (“Chorizo”), and cheese (“San Simón da Costa”, “Idiazábal” and “Humus”) in order to compare their PAH content. Three of the four selected products have quality labels (Protected Designation of Origin – PDO and Protected Geographical Indication – PGI) that differentiate them and provide added value. So, “Pan de Cea” is bread with PGI, “Pimentón de la Vera” is a paprika with PDO and “San Simón da Costa” and “Idiazábal” are two types of cheeses with PDO. All these products are approved by the Council Regulation (EC) No. 510/2006 of 20 March 2006 on the protection of geographical indications and designations of origin for agricultural products and foodstuffs (EC, 2006b).

Due to the great impact of these products on the Spanish economy because of their characteristic taste, high nutritional value and high level and variety of production, the principal aim of this study was the evaluation of 10 PAHs (PAH8 indicated by EFSA plus the widely distributed fluoranthene (F) and pyrene (P)) in these selected traditional smoked foods, taking into account that the smoking step is a critical point in the increase in PAHs levels.