Contamination of traditionally smoked cheeses with polycyclic aromatic hydrocarbons and biogenic amines

Focus on Histamine Production During Cheese Manufacture and Processing: A Review

Histamine (HIS) intoxication is a poisoning caused by histamine in food. Cheese is one of the most common dairy products associated with histamine levels which vary depending on the processing methods. The final content of histamine in cheese is influenced by intrinsic and extrinsic factors, their interactions, and contamination stemming from food processing. The application of control measures may be useful to inhibit/reduce production during cheese manufacture and processing but have a limited effect. To reduce histamine intoxication outbreaks from cheese consumption the introduction of quality control programs and appropriate risk mitigation options should be applied along the dairy chain from an overall perspective of food safety based on individual susceptibility and consumer sensitivity. As key food safety, this topic should be considered in future regulations in dairy products because the lack of a clear law on HIS limits in cheese may result in a significant potential deviation from the EU food safety strategy.

Combination of SPE and fluorescent detection of AQC-derivatives for the determination at sub-mg/L levels of biogenic amines in dairy products

Biogenic amines (BAs) are compounds generated by decarboxylation of their amino acid precursors. Their intake, even at low concentrations, can lead to several types of health problems in sensitive individuals. As they can be easily formed in fermented dairy products, their quantitative determination is very relevant. In the present paper, a method for the quantitative determination of four biogenic amines in different dairy products has been developed, validated and applied to 37 samples of milk, 23 of yogurt, and 14 of kefir. Amines were selectively extracted using solid phase extraction, subsequently derivatizatized with 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate and further determined by High Performance Liquid Chromatography with fluorescence detection. The method's sensitivity was highly satisfactory, with limits of detection lower than 0.2 mg/L. Optimal linearity and repeatability were also achieved. BAs were not detected in most of the milk samples, but they were found frequently at high levels in yogurt and kefir samples, reaching values of up to 79 mg/kg total BAs in kefir samples. Levels measured should not be a cause for concern for the population at large, but should be known by BAs-sensitive individuals.

Evaluation of Polycyclic Aromatic Hydrocarbons in Smoked Cheeses Made in Poland by HPLC Method

Smoked cheeses are particularly popular among consumers for their flavor and aroma. Of interest, therefore, is the health aspect related to the likelihood of polycyclic aromatic hydrocarbons (PAHs), which are known carcinogens found in smoked products. Thus, the purpose of this study was to evaluate the occurrence of 15 polycyclic aromatic hydrocarbons (PAHs) in smoked and non-smoked cheeses purchased in Poland to monitor their safety. The level of selected PAHs in cheese samples was determined using the HPLC-DAD-FLD method. Most of the cheeses tested met the maximum level of benzo[a]pyrene (2 μg/kg) and the sum of benz[a]anthracene, chrysene, benzo[b]fluoranthene and benzo[a]pyrene (12 μg/kg) established for these products. However, all the cheeses studied in this work had relatively low amounts of the sum of these compounds compared to the information available in the cheese literature, ranging from <LOD to 24.5 μg/kg. This amount does not pose a health risk to consumers. The predominant PAHs found were naphthalene, phenanthrene, fluorene and acenaphthene. Benzo[a]pyrene, the marker compound representing carcinogenic PAHs, was found in 100% and 0% of Polish smoked and non-smoked cheeses, respectively. Although there are currently no regulations for smoked cheeses and maximum concentrations of PAHs in this type of food product, control of PAHs content in cheeses is important due to the mutagenic and carcinogenic potential of these chemicals.

Analytical strategies for the determination of biogenic amines in dairy products

Biogenic amines (BA) are mainly produced by the decarboxylation of amino acids by enzymes from microorganisms that emerge during food fermentation or due to incorrectly applied preservation processes. The presence of these compounds in food can lead to a series of negative effects on human health. To prevent the ingestion of high amounts of BA, their concentration in certain foods needs to be controlled. Although maximum legal levels have not yet been established for dairy products, potential adverse effects have given rise to a substantial number of analytical and microbiological studies: they report concentrations ranging from a few mg/kg to several g/kg. This article provides an overview of the analytical methods for the determination of biogenic amines in dairy products, with particular focus on the most recent and/or most promising advances in this field. We not only provide a summary of analytical techniques but also list the required sample pretreatments. Since high performance liquid chromatography with derivatization is the most widely used method, we describe it in greater detail, including a comparison of derivatizing agents. Further alternative techniques for the determination of BA are likewise described. The use of biosensors for BA in dairy products is emerging, and current results are promising; this paper thus also features a section on the subject. This review can serve as a helpful guideline for choosing the best option to determine BA in dairy products, especially for beginners in the field.

Trace-Level Determination of Polycyclic Aromatic Hydrocarbons in Dairy Products Available in Spanish Supermarkets by Semi-Automated Solid-Phase Extraction and Gas Chromatography-Mass Spectrometry Detection

Polycyclic aromatic hydrocarbons (PAHs) have been classified as priority pollutants by the U.S. Environmental Protection Agency (EPA) and the European Commission on the grounds of their carcinogenic, mutagenic and teratogenic properties. Because of their ubiquity in industrial processes and the environment, PAHs can reach milk and dairy products and, eventually, humans. In this work, a new method was developed to detect and quantify sixteen of the EPA’s priority PAHs in commercial milk and dairy products. The method involves liquid−liquid extraction (LLE) followed by semi-automated solid-phase extraction (SPE) to clean up and preconcentrate the analytes prior their detection and quantification by gas chromatography−mass spectrometry (GC−MS). The proposed method provided high precision (relative standard deviation < 11.5%), recoveries of 80−107% and low detection limits (1−200 ng/kg). The method was applied to analyze 30 dairy products, the majority of which contained some PAH at concentrations from 7.1 to 1900 ng/kg. The most-detected analytes were the lighter PAHs (naphthalene, acenaphthylene, fluorene and phenanthrene). None of the samples, however, contained more than four PAHs.

Influence of Plant Extract Addition to Marinades on Polycyclic Aromatic Hydrocarbon Formation in Grilled Pork Meat

Marinating is one of the most common methods of pre-processing meat. Appropriate selection of marinade ingredients can influence the physicochemical properties of the meat and can reduce the level of polycyclic aromatic hydrocarbons (PAHs) in the final product. The effects of the inclusion of natural plant extracts such as bay leaf (BL), black pepper (BP), turmeric (TU), jalapeno pepper (JP) and tamarind paste (TA) in marinades on the physicochemical properties of grilled pork neck were studied. The addition of spice extracts to marinades increased the proportion of colour components L* and b*. The use of TU, TA, JP, MX and C marinades lowered the hardness and pH of the meat. The highest phenolic compound levels were observed in the case of the mixture of all extracts (MX) and JP marinades, and the highest total antioxidant capacity was exhibited by the BL and MX marinades. The highest PAH content was recorded in the CON marinade (Σ12PAH 98.48 ± 0.81 µg/kg) and the lowest in the JP marinade (4.76 ± 0.08 µg/kg), which had the strongest, statistically significant reducing effect (95% reduction) on PAH levels. Analysis of correlation coefficients showed a relationship between the total antioxidant capacity of the marinades and the PAH content in grilled pork.

Nutritional value and organoleptic assessment of traditionally smoked cheeses made from goat, sheep and cow's milk

The use of small ruminant milk for smoked cheese production makes it possible to incorporate valuable nutrients into the diet, especially as the consumption of unprocessed sheep or goat's milk is low compared to that from cows. Smoking of food not only prolongs its shelf-life but also improves its flavour. Taking the fact that many consumers do not accept some organoleptic properties of milk from small ruminants into account, the aim of the study was to assess and compare the organoleptic and nutritional properties of traditionally smoked cheeses made from goat, sheep and cow's milk. The analysed cheeses differed in terms of dry matter content and its components such as protein and fat. Their acidity was comparable, except for the sample made of raw goat's milk, which was characterised by a relatively high pH value (6.12 ± 0.06). The highest content of CLA (2.30 ± 0.04%), as well as the highest share of unsaturated and polyunsaturated fatty acids, was determined in the cheese made from sheep's milk. Moreover, the content of butyric and caproic free fatty acids in cheeses made from goat's milk was found to be several times higher than in the other analysed cheeses. The organoleptic assessment did not reveal any significant differences between the cheeses produced at small, private farms and in industrial conditions, or between different types of cheese, regardless of the type of milk from which they were produced.

Polycyclic Aromatic Hydrocarbons in Foods: Biological Effects, Legislation, Occurrence, Analytical Methods, and Strategies to Reduce Their Formation

Polycyclic aromatic hydrocarbons (PAHs) are chemical compounds comprised of carbon and hydrogen molecules in a cyclic arrangement. PAHs are associated with risks to human health, especially carcinogenesis. One form of exposure to these compounds is through ingestion of contaminated food, which can occur during preparation and processing involving high temperatures (e.g., grilling, smoking, toasting, roasting, and frying) as well as through PAHs present in the soil, air, and water (i.e., environmental pollution). Differently from changes caused by microbiological characteristics and lipid oxidation, consumers cannot sensorially perceive PAH contamination in food products, thereby hindering their ability to reject these foods. Herein, the occurrence and biological effects of PAHs were comprehensively explored, as well as analytical methods to monitor their levels, legislations, and strategies to reduce their generation in food products. This review updates the current knowledge and addresses recent regulation changes concerning the widespread PAHs contamination in several types of food, often surpassing the concentration limits deemed acceptable by current legislations. Therefore, effective measures involving different food processing strategies are needed to prevent and reduce PAHs contamination, thereby decreasing human exposure and detrimental health effects. Furthermore, gaps in literature have been addressed to provide a basis for future studies.