Chemical safety of meat and meat products.

Since the Second World War the consumer behaviour in developed countries changed drastically. Primarily there existed the demand for sufficient food after a period of starvation, afterwards the desire for higher quality was arising, whereas today most people ask for safe and healthy food with high quality. Therefore a united approach comprising consistent standards, sound science and robust controls is required to ensure consumers' health and to maintain consumers' confidence and satisfaction. Chemical analysis along the whole food chain downstream (tracking) from primary production to the consumer and upstream (tracing) from the consumer to primary production is an important prerequisite to ensure food safety and quality. In this frame the focus of the following paper is the "chemical safety of meat and meat products" taking into account inorganic as well as organic residues and contaminants, the use of nitrite in meat products, the incidence of veterinary drugs, as well as a Failure Mode and Effect Analysis (FMEA) system assessing (prioritizing) vulnerable food chain steps to decrease or eliminate vulnerability.

Gas chromatography-mass spectrometry (GC-MS) method for the determination of 16 European priority polycyclic aromatic hydrocarbons in smoked meat products and edible oils.

A gas chromatography-mass spectrometry (GC-MS) method was developed for the analysis of 15 polycyclic aromatic hydrocarbons (PAHs) highlighted as carcinogenic by the Scientific Committee on Food (SCF) plus benzo[c]fluorine (recommended to be analysed by the Joint FAO/WHO Expert Committee on Food Additives (JECFA) in fat-containing foods such as edible oils and smoked meat products. This method includes accelerated solvent extraction (ASE) and the highly automated clean-up steps gel permeation chromatography (GPC) and solid-phase extraction (SPE). Using a VF-17ms GC column, a good separation of benzo[b]fluoranthene, benzo[j]fluoranthene and benzo[k]fluoranthene was achieved. Futhermore, the six methylchrysene isomers and the PAH compounds with a molecular weight of 302 Daltons in fat-containing foods attained a better chromatographic separation in comparison with a 5-ms column. The reliability of the analytical method for edible oils was demonstrated by the results from a proficiency test. Measurements with GC-high-resolution mass spectroscopy (HRMS) and gas chromatography-mass selective detection (GC-MSD) led to comparable results. A survey of the 16 PAHs in 22 smoked meat products showed concentrations in the range < 0.01-19 microg kg(-1). The median concentration for benzo[a]pyrene was below 0.15 microg kg(-1).

Strong increase in hydroxy fatty acids derived from linoleic acid in human low density lipoproteins of atherosclerotic patients.

Linoleic acid is the most abundant fatty acid in human low density lipoproteins (LDL). Oxidation of LDL transforms linoleic acid to hydroperoxyderivatives. These are converted to 9-hydroxy-10,12-octadecadienoic acid (9-HODE) and 13-hydroxy-9,11-octadecadienoic acid (13-HODE). 9-HODE is much more abundant in oxidized LDL than other lipid peroxidation products and therefore an indicator of lipid peroxidation (LPO). In this study the 9-HODE content in the LDL of 19 obviously healthy volunteers and 17 atherosclerotic patients was investigated. The level of 9-HODE obtained from LDL of young atherosclerotic patients (aged 36-47 years) was increased by a factor of 20 when compared with samples from healthy volunteers of the same age group. The content of 9-HODE in the LDL of atherosclerotic patients aged between 69 and 94 years increased 30-100 fold when compared with young healthy individuals, but when compared with 'healthy' individuals of the same age group it was only 2-3 fold increased. Obviously, as individuals grow older LDL becomes more and more oxidized. Consequently, assuming that LDL oxidation is a precondition for atherosclerosis--older individuals will suffer from atherosclerosis, even if no easy detectable visible signs of this disease are recognizable. According to 9-HODE determination, the onset of the disease starts slowly in most individuals at around 50 years of age.

Increased levels of lipid oxidation products in rheumatically destructed bones of patients suffering from rheumatoid arthritis.

The new indicator for lipid peroxidation (LPO) processes--9-hydroxy-10,12-octadecadienoic acid (9-HODE)--was used to investigate, whether LPO processes are increased in destructed bone material of patients suffering from rheumatoid arthritis (RA) in comparison to surrounded non destructed bone material. The HODE content in destructed bones exceeded that of non destructed ones of the same patient for a factor of about 3. In addition similar increases in leukotoxines and epoxy oleic acid in the destructed bone material were observed, indicating an increase of LPO processes in affected bone parts of patients.

Increased levels of lipid oxidation products in low density lipoproteins of patients suffering from rheumatoid arthritis.

9-Hydroxy-10,12-octadecadienoic acid (9-HODE) and 13-hydroxy-9,11-octadecadienoic acid (13-HODE) are accumulated in the low density lipoproteins of patients suffering from rheumatoid arthritis for a factor of 20-50 compared to healthy individuals of the same age. Both acids, derived by lipid peroxidation of linoleic acid, induce the release of interleukin 1 beta. The latter induces bone degression. The genesis of 9- and 13-HODE seems therefore to be an important factor in the development and progression of rheuma; in addition 9-HODE was reported to be a stimulus of inflammation, comparable to leukotrienes.

Increase in hydroxy fatty acids in human low density lipoproteins with age.

The content of hydroxy fatty acids in low density lipoprotein (LDL) of healthy volunteers aged between 22 and 87 years without any signs of atherosclerosis or other age-dependent diseases was investigated. The level of hydroxy fatty acids obtained from LDL increases during life time: clinically healthy persons between 56 and 66 years showed a 3- to 4-fold increase compared to young volunteers. This level increased in samples of probands aged 68 to 74 years compared to samples of young people for a factor of 10-20 and in samples of probands aged 78 to 87 years for a factor of 30-40. These hydroxy acids--generated mainly from hydroperoxy acids on linoleic acid and only partly from arachidonic acid--are obviously parameters of the LDL oxidation stage. About 90% of the total amount of hydroxy fatty acid were free fatty acids. The distribution patterns of the monohydroxy derivatives of linoleic and arachidonic acid indicate that they originate mainly from autocatalytic processes. The individual level of hydroxy acids is probably an indicator of the biological age.

Plasmalogens and their oxidative degradation products in low and high density lipoprotein.

The kinetics of the autoxidation reaction of LDL and HDL with Fe2+/ascorbate was investigated. Aldehydes derived from plasmalogens were determined by conversion to 2-alkyl-1,3-dithiolanes. Their oxidation products, 2-hydroxy-aldehydes, were trapped by reaction with pentafluorobenzylhydroxylamine. After derivatisation, the pentafluorobenzyloximes could be separated from other compounds by thin-layer chromatograpy. They were detected by gas chromatography applying an electron capture detector. LDL plasmalogens are oxidized nearly completely after 180 min while HDL plasmalogens suffer oxidation only to 5%. Oxidation of linoleic and arachidonic acid was investigated by simultaneous determination of 2-hydroxyheptanal.