Marek Roszko

Profiles and concentrations of heterocyclic aromatic amines formed in beef during various heat treatments depend on the time of ripening and muscle type.

Heterocyclic Aromatic Amine (HAA) profiles and concentrations depended on several factors. The largest changes in the HAA profile were observed in meat ripened (chill stored) for 5-10 days. Amines whos concentration varied most prominently included: Phe-P 1, harmane, AαC, IQ, IQx, PhIP, MeAαC, and MeIQx. HAA concentrations were strongly correlated with concentrations of the above compounds. Time of storage significantly affected the HAA profile and concentration. The profile changed dynamically for storage times up to 10 days. For longer times the profile stabilized, only the HAA content increased. A novel, highly precise and accurate HAA analytical method was developed for this study. Results may help to optimize meat processing technology from the point of view of reducing concentration of HAA formed during heat treatment, including the most carcinogenic; IQ, IQx, MeIQx and PhIP amines.

Application of the SPE reversed phase HPLC/MS technique to determine vitamin B12 bio-active forms in beef.

Vitamin B12 is an animal origin nutrient of a substantial importance in human diet. Its concentration in foodstuffs is low and its chemical forms are diverse, which significantly hampers its precise determination. The determination method of choice is HPLC (high performance liquid chromatography) coupled with inductively-coupled-plasma mass spectrometry (ICP-MS). The main disadvantage of this method is high instrumentation cost and complexity of handling. The aim of this work was to develop a novel approach for determination of vitamin B12 bio-active forms in beef and beef liver. The proposed method comprises the following steps: (i) vitamin B12 is cleaved off from peptides using thermal denaturation in a weakly acidic environment; (ii) sample is cleaned-up using liquid-liquid extraction and reversed phase solid phase extraction; and finally (iii) vitamin B12 is determined using HPLC and single-quadrupole mass spectrometer with ESI source. Vitamin B12 concentrations in various beef meats were in the 2.84-3.95 μg 100g(-1) range. Average B12 concentration in beef liver was 153,60 μg 100g(-1) (n = 15). Major forms of B12 present in beef meat include adenosine cobalamin (AdoCbl) and in smaller quantities hydroxycobalamin (OHCbl). Major forms of vitamin B12 present in beef liver include OHCbl (48.2%), AdoCbl (33.8%), methylocobalamin (MeCbl, 16.3%), and cyanocobalamin (CNCbl, 1.7%). Thermal treatment noticeably decreases B12 the content in meat. Depending on conditions of treatment, B12 concentrations in the 1.04-2.20 μg 100g(-1) range were found in processed meats.

Fumonisins in plant-origin food and fodder – a review

Fumonisins are mycotoxins produced by the Fusarium group of fungi commonly found on crops, mainly on maize. Some data suggest that as much as 25% of world crops may be lost because of mycotoxin contamination. Therefore, researchers in many countries (particularly in those in which relatively large amounts of maize are directly consumed by humans) are concerned with fumonisin levels in plant-origin foodstuffs and feeds available in their local markets. There is no doubt the levels are strongly correlated with the climate conditions prevailing in the region in which the maize was cultivated: the hotter the climate, the more serious the problem. Negative consequences of consumption of fumonisin-contaminated food by humans include an increased risk of oesophagus cancer and decreased body mass growth. In recent years some trials have been undertaken to reduce fumonisin levels in food and feed by the application of isothiocyanates naturally occurring in plants or peptidoglycans isolated from lactic acid bacteria (LAB). The results of these studies suggested that some reduction in contamination levels might be achieved. Additionally, some recent studies indicate that Sphingopyxis sp. bacteria produce enzymes that are able to break down the fumonisin molecule. Some fumonisins present in food may be bound/coupled with other compounds, and therefore difficult to detect. Such complexes in which the toxins are masked or hidden may even be at higher levels than the not-bound (free) molecules. The problem of how to evaluate effectively and efficiently the concentration of fumonisins in various foodstuffs is therefore a real-life challenge for scientists.

SIMULTANEOUS DETERMINATION OF FREE AMINO ACIDS, L-CARNOSINE, PURINE, PYRIMIDINE, AND NUCLEOSIDES IN MEAT BY LIQUID CHROMATOGRAPHY/SINGLE QUADRUPOLE MASS SPECTROMETRY

A novel approach to single-run determination of 25 free amino acids, L-carnosine, 4 nitrogen bases (purine and pyrimidine), and 5 nucleosides in unpurified biological samples is reported. The analytes were extracted from the sample, derivatized with dansyl chloride, and analyzed using RP-HPLC-DAD-ESI-MS. The reported method features high sensitivity (LOQs in 5–10 ng mL−1 range), wide linearity range with r > 0.94, and high precision (intra-day RSD within the 0.1–4.2% range). Analyte average recovery coefficient was in the 70.1–111.3% range. The method was used to determine levels of free amino acids, L-carnosine, nitrogen bases, and nucleosides in beef (strip loin). Evolution of concentrations of the studied compounds during meat storage processes (vacuum packing, cold storage) was also investigated.

Separation of polychlorinated dibenzo-p-dioxins/furans, non-ortho/mono/di/tri/tetra-ortho-polychlorinated biphenyls, and polybrominated diphenyl ethers groups of compounds prior to their determination with large volume injection gas chromatography—Quadrupole ion storage tandem mass spectrometry

Polychlorinated dibenzo-p-dioxins/furans (PCDD/Fs), polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) are important environmental contaminants. Their maximum legally allowable levels in food and environment are in the low pg g(-1) range. Therefore some highly selective and sensitive analytical methods must be used to determine them. Prior to final determination by GC/MS the cleaned-up samples have to be split into some fractions in view of large differences in concentrations of various analytes and existence of numerous chromatographic co-elutions (which in any case cannot be fully avoided). The aim of this study was to: (i) develop a robust, time-saving analytical method to isolate, clean-up and fractionate PCBs, PBDEs and PCDD/Fs prior to their determination with gas chromatography/ion trap mass spectrometry; (ii) assess method performance using laboratory validation data and some certified reference materials; (iii) use the developed method to assess PCB/PBDE/PCDD/F levels in samples of commercially available food. A combination of alumina, florisil, modified silica gel and two carbon columns were used for sample cleanup and fractionation. Separate fractions containing dioxins/furans, PBDE, non-ortho, mono-ortho and di-/tri-/tetra-ortho PCBs were obtained. The method statistical parameters were compatible with 1883/2006 EC Regulation (80-120%, RSD below 15%). The method performance was successfully used to evaluation of some real life food samples.

Effect of baking on reduction of free and hidden fumonisins in gluten-free bread.

The aim of the present work was to assess the influence of the baking process on the fumonisin content in gluten-free bread. The dough was made using two methods: without sourdough and with sourdough. Fumonisins were determined using high-performance liquid chromatography with ion-trap mass spectrometry. This study showed that the bread baking process caused a statistically significant drop in the mean concentration of free fumonisins: the reduction levels were 30 and 32% for the direct and sourdough-based methods, respectively. The lower reduction after baking was observed for hidden fumonisins: 19 and 10%, respectively. The presence of some compounds (such as proteins or starch) capable of stabilizing fumonisins during the baking process might be responsible for the observed increase in the hidden-to-free ratio from an initial 0.72 in flour to 0.83 in bread made from sourdough and to 0.95 in sourdough-free bread.

Polychlorinated biphenyls (PCBs), polychlorinated diphenyl ethers (PBDEs) and organochlorine pesticides in selected cereals available on the Polish retail market.

Polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), and organochlorine pesticides (DDT, HCH, HCB, chlordane, endrin, dieldrin, aldrin, nitrophene, metoxychlor) are man-made chemicals manufactured for numerous applications. The aim of this study was to assess levels of PCBs, PBDEs, and organochlorine pesticides in selected types of cereals available on the Polish retail market. 191 samples of various cereals have been analyzed in total. Average EC6 concentrations ranged from 56.4 (snacks) to 442.2 pg g(-1) (bran) while the concentration of 12 dioxin-like PCBs was in 15 (groats)-37.6 pg g(-1) (snacks) range. Mean dioxin equivalency concentration calculated as lower bound results in 2005 TEF values amounted to 0.120 ± 0.445 pg TEQ g(-1), while 0.091 ± 0.338 pg TEQ g(-1) if 1998 TEF values were used. Average concentration of all 14 studied BDEs (∑14 BDE) was 112 ± 80 pg g(-1), while average concentration of 13 BDEs excluding BDE #209 was only 15 ± 6 pg g(-1). Pesticide concentrations observed in the analyzed samples were generally low in comparison to maximum residue levels (MRLs) actually permitted by the European Union. However, MRLs were exceeded in 7 out of all 191 analyzed samples. Total concentration of DDT isomers in one of the tested bran samples was as high as 0.053 mg kg(-1). DMDT concentrations slightly above MRL = 0.01 mg kg(-1)were observed in 6 other samples (2 × bran, 1 × children porridge, 2 × snacks and 1 × bread). This study has shown that levels of PCBs, PBDEs and organochlorine pesticides in cereal products available on the Polish market are generally low. However, elevated levels of individual pollutants were observed in several instances.

Application of molecularly imprinted polymers to determine B1, B2, and B3 fumonisins in cereal products

The aim of this study was to develop an analytical method for qualitative and quantitative determination of the B(1), B(2,) and B(3) fumonisins in cereal products. A LC coupled to an IT-MS was used as the analytical instrument. The AFFINIMIP FumoZON Molecularly Imprinted Polymer SPE cartridges (Polyintell) were used to isolate fumonisins from the analyzed samples and the clean-up step. Statistical parameters evaluated in some validation experiments were as follows: mean recovery 95-106%, precision <17% (expressed as recovery RSD). The developed method was used to determine fumonisins in 49 cereals (42 maize-based and seven wheat-based products). In most cases, concentrations of the studied compounds found in the analyzed samples were low. The highest total concentration of the B(1), B(2), and B(3) fumonisins was found in maize flour samples (range, 26-1102 μg/kg, mean 498 μg/kg).

Application of semi-permeable membrane dialysis/ion trap mass spectrometry technique to determine polybrominated diphenyl ethers and polychlorinated biphenyls in milk fat.

Polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) are hazardous food contaminants, their maximum legally allowable levels in food and environment are in the low pgg(-1) range. Therefore some highly selective and sensitive analytical methods must be used to determine them. The 96/23/EC Directive implemented by EC Decision of 12 August 2002 requires recovery rate of an analyte at a concentration below 1 ng g(-1) within the 50-120% range at relative standard deviation (RSD) as low as possible. A method to determine low level PCBs and PBDEs in milk fat based on the semi-permeable membrane dialysis/ion trap GC MS technique was developed. Validation experiments proved that the method performance was within bounds set by the currently standing UE regulations. Recovery rates calculated on the basis of labeled internal standards for majority of the studied indicator PCB congeners and PBDE congeners were close to 100% at RSD below 20%. Also, dioxin-like PCBs recovery rates were compatible with the 1883/2006 EC Regulation (80-120%, RSD below 15%). The developed method turned out to be linear within a far broader concentration range than the studied 0.0025-10 pg μL(-1) range entirely sufficient for analyses of PCB and PBDE in milk fat. Within that range coefficient of linear correlation (R(2)) of calibration curves exceeded 0.98.

Seasonal and geographical variations in levels of polychlorinated biphenyls (PCB) and polybrominated diphenyl ethers (PBDE) in Polish butter fat used as an indicator of environmental contamination

The aim of this study was to evaluate the seasonal variation/geographical distribution of environmental concentration of polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) across Poland using butter fat as an indicator of the contaminants. The average concentration of six indicator PCBs determined in the studied samples was 1500 pg g–1 fat. The average concentration of 12 dioxin-like PCBs expressed as lower-bound dioxin-equivalent toxicity was 0.684 pg TEQ g−1 fat. The average total concentration of 14 investigated PBDE congeners was 105 pg g−1 fat. Statistically significant concentration differences between summer and winter samples were found. The results of this study indicate also a significant geographical diversification of butter contamination reflecting regional differences in environmental contamination. The seasonal variation of PBDE profiles evidences transformation of PBDE within the environment.