The occurrence of volatile and non-volatile N-nitrosamines in cured meat products from the Danish market.

Several epidemiological studies emphasize the consumption of processed meat products as a risk factor of colorectal cancer, linking N-nitrosamines (NAs) formed during nitrite curing to this cancer risk. The occurrence of volatile N-nitrosamines (VNAs) has over the years been intensively studied while the knowledge on the occurrence and toxicity of non-volatile N-nitrosamines (NVNAs) is still limited. Therefore, this study focuses on quantification of both VNAs and NVNAs in a large selection of processed meat products. For this purpose, a robust, specific and sensitive method allowing analysis of seven VNAs and two NVNAs was optimized and validated using kassler, sausage, and salami. The limit of quantification achieved was 0.1-0.5 ng·g-1 for most of the VNA, and 2.3-4.2 ng·g-1 for the NVNA. In one hundred commercial samples N-nitroso-thiazolidine-4-carboxylic acid (NTCA) was the most frequently detected (97 samples) among all target NAs and it was found at concentrations ranging from 3.1 ng·g-1 to 1660 ng·g-1. The samples contained relatively low mean levels of the individual VNAs (≤1 ng·g-1). The levels of N-nitrosodimethylamine (NDMA), N-nitrosopyrrolidine (NPYR), and N-nitrosopiperidine (NPIP) ranged from non-detectable to 3.8, 10.8 and 2.9 ng·g-1, respectively. A correlation between the detected residual levels of nitrite and/or nitrate and concentrations of individual NAs could not be demonstrated. Based on principle component analysis (PCA) some correlations between salami, sausage and bacon and NAs could be shown.

Dietary exposure to volatile and non-volatile N-nitrosamines from processed meat products in Denmark.

Recent epidemiological studies show a positive association between cancer incidence and high intake of processed meat. N-nitrosamines (NAs) in these products have been suggested as one potential causative factor. Most volatile NAs (VNAs) are classified as probable human carcinogens, whereas the carcinogenicity for the majority of the non-volatile NA (NVNA) remains to be elucidated. Danish adults (15-75 years) and children (4-6 years) consume 20 g and 16 g of processed meat per day (95th percentile), respectively. The consumption is primarily accounted for by sausages, salami, pork flank (spiced and boiled) and ham. This consumption results in an exposure to NVNA of 33 and 90 ng kg bw(-1) day(-1) for adults and children, respectively. The exposure to VNA is significantly lower amounting to 0.34 and 1.1 ng kg bw(-1) day(-1) for adults and children, respectively. Based on a BMDL10 of 29 µg kg bw(-1) day(-1) a MOE value ≥17,000 was derived for the exposure to NA known to be carcinogenic (VNA including NSAR), indicating an exposure of low concern. The exposure to the NVNA is substantially higher and if found to be of toxicological significance the exposure may be of concern.

Formation and mitigation of N-nitrosamines in nitrite preserved cooked sausages.

Literature on formation and mitigation of N-nitrosamine (NA) and especially non-volatile NA (NVNA) in meat products is scarce and the present study is therefore a relevant contribution to the field. We found positive correlation between the levels of N-nitrosopiperidine (NPIP), N-nitrosohydroxyproline (NHPRO), N-nitrosoproline (NPRO), N-nitrosothiazolidine-4-carboxylic acid (NTCA) and N-nitroso-2-methyl-thiazolidine-4-carboxylic acid (NMTCA) and the amount of nitrite added to cooked pork sausages. The levels studied were 0, 60, 100, 150, 250 and 350 mg kg(-)(1). The levels of N-nitrosodimethylamine (NDMA) and N-nitrosopyrrolidine (NPYR) remained at or below limit of quantification. Erythorbic acid inhibited the formation of NHPRO, NPRO, NPIP and NTCA. This inhibition was for NTCA and NMTCA counteracted by addition of free iron. Ascorbyl palmitate had less inhibitory effect than erythorbic acid and a combination of the two provided no further protection. Increasing the black pepper content increased the levels of NPIP and NMTCA. Only slight effects of increased fat content and addition of tripolyphosphate were observed.

Simultaneous determination of volatile and non-volatile nitrosamines in processed meat products by liquid chromatography tandem mass spectrometry using atmospheric pressure chemical ionisation and electrospray ionisation.

A sensitive, selective and generic method has been developed for the simultaneous determination of the contents (µgkg(-1) range) of both volatile nitrosamines (VNA) and non-volatile nitrosamines (NVNA) in processed meat products. The extraction procedure only requires basic laboratory equipment and a small volume of organic solvent. Separation and quantification were performed by the developed LC-(APCI/ESI)MS/MS method. The method was validated using spiked samples of three different processed meat products. Satisfactory recoveries (50-130%) and precisions (2-23%) were obtained for eight VNA and six NVNAs with LODs generally between 0.2 and 1µgkg(-1), though for a few analyte/matrix combinations higher LODs were obtained (3 to 18µgkg(-1)). The validation results show that results obtained for one meat product is not always valid for other meat products. We were not able to obtain satisfactory results for N-nitrosohydroxyproline (NHPRO), N-nitrosodibenzylamine (NDBzA) and N-nitrosodiphenylamine (NDPhA). Application of the APCI interface improved the sensitivity of the method, because of less matrix interference, and gave the method a wider scope, as some NAs were ionisable only by APCI. However, it was only possible to ionize N-nitroso-thiazolidine-4-carboxylic acid (NTCA) and N-nitroso-2-methyl-thiazolidine-4-carboxylic acid (NMTCA) by ESI. The validated method was applied for the analysis of processed meat products and contents of N-nitrosodimethylamine (NDMA), N-nitrosopyrrolidine (NPYR), N-nitrosomethylaniline (NMA), N-nitrosoproline (NPRO), NTCA, and NMTCA were found in one or several nitrite cured meat products, whereas none were detected in non-nitrite cured bacon.