Evaluation of hamburgers and hot dogs for the presence of mutagens

In vitro mutagenicity assessment of fried meat-based food from mass catering companies

The current article aimed to evaluate the in vitro mutagenicity of ten fried meat-based food extracts obtained from different catering companies from Navarra (Spain). A miniaturized 6-well version of the Ames test in Salmonella typhimurium TA98, and the in vitro micronucleus test (OECD TG 487) in TK6 cells were performed. None of the ten extracts of fried meat-based food induced gene mutations in S. typhimurium TA98 with or without metabolic activation, but five induced chromosomal aberrations after 24 h treatment of TK6 without metabolic activation. More studies are needed to check the biological relevance of these in vitro studies.

Street food research worldwide: a scoping review

BACKGROUND

Street foods vary with respect to their nutritional value and safety characteristics and contribute to a sizable proportion of food intake in many populations worldwide. Therefore, the present study aimed to describe the coverage in the scientific literature of different health-related and socio-economic aspects of street food consumption and trading.

METHODS

Three electronic databases (searched from inception to 16 October 2017), a hand-search of relevant journals and backward citation tracking were used to identify eligible scientific articles with a main objective of investigating or reporting specific results on health-related or socio-economic aspects of street food. Papers published in English, Portuguese, French, Spanish or Italian, as well as English abstracts of papers published in other languages, were assessed. The selected articles were evaluated by two independent researchers and described according to year of publication, geographical distribution, definition of street food, main topics addressed and target population.

RESULTS

In total, 441 papers were selected. The number of publications has increased in recent years, almost half of them being published after 2012. Almost three-quarter of the articles were from Africa or Asia. Most studies addressed food safety (85.5%), whereas street food availability and consumption were much less frequently investigated (30.3%). The focus of the studies was usually the food (mostly its microbiological contamination) and the vendors (mostly their food handling), whereas consumers and vending sites were seldom evaluated. More than half of the studies did not specify a definition for street food.

CONCLUSIONS

Efforts are needed for a more widespread and comprehensive assessment of different issues related to street food availability and consumption in different settings, especially regarding street food offer, nutritional composition, and patterns of purchase and consumption by the population.

Dietary exposure of Nigerians to mutagens and estrogen-like chemicals

Food and drinking water are poorly delineated sources of human exposure to chemical food mutagens and endocrine-disrupting chemicals. In this study, we investigated the presence of mutagens and chemicals exhibiting estrogenic activity in the daily diet of Nigerians, using in vitro assays. Commercially processed foods or snacks and various brands of pure water sachets were extracted by solid-phase extraction and liquid-liquid extraction, respectively. Mutagenicity was determined by the conventional Ames test and two complementary assays on two strains of Salmonella (TA 100 and TA 98), while the estrogenic activity was assessed by a yeast bioluminescent assay, using two recombinant yeast strains (Saccharomyces cerevisiae BMAEREluc/ERα and S. cerevisiae BMA64/luc). A third of the food varieties investigated (chin-chin, hamburger, suya and bean cake) were mutagenic in all three assays, either in the presence or absence of S9 mix. Of the packed water samples, five out of the sixteen investigated (31%), were found to be estrogenic, with estradiol and bisphenol A equivalents ranging from 0.79 to 44.0 ng/L and 124.2 to 1,000.8 ng/L, respectively. Hence, although the current situation in Nigeria does not appear to be substantially worse than, e.g., in Europe, regular monitoring is warranted in the future.

Separation of heteroaromatic amines in food products

In recent years, many studies have dealt with the role of certain heteroaromatic amines (HAs) as mutagenic compounds, and their occurrence in foodstuffs. Here we examine the determination of HAs, focusing on the analytical strategies for their extraction and preconcentration from several matrices. We summarise the properties of heteroaromatic amines and the main drawbacks involved in their analysis, and then concentrate on the separation procedures, sorbents and solvents used in the sample treatment. We discuss the requirements of the analytical techniques and the strategies most frequently followed to achieve accurate results.

Creatine and creatinine metabolism

The goal of this review is to present a comprehensive survey of the many intriguing facets of creatine (Cr) and creatinine metabolism, encompassing the pathways and regulation of Cr biosynthesis and degradation, species and tissue distribution of the enzymes and metabolites involved, and of the inherent implications for physiology and human pathology. Very recently, a series of new discoveries have been made that are bound to have distinguished implications for bioenergetics, physiology, human pathology, and clinical diagnosis and that suggest that deregulation of the creatine kinase (CK) system is associated with a variety of diseases. Disturbances of the CK system have been observed in muscle, brain, cardiac, and renal diseases as well as in cancer. On the other hand, Cr and Cr analogs such as cyclocreatine were found to have antitumor, antiviral, and antidiabetic effects and to protect tissues from hypoxic, ischemic, neurodegenerative, or muscle damage. Oral Cr ingestion is used in sports as an ergogenic aid, and some data suggest that Cr and creatinine may be precursors of food mutagens and uremic toxins. These findings are discussed in depth, the interrelationships are outlined, and all is put into a broader context to provide a more detailed understanding of the biological functions of Cr and of the CK system.

Heterocyclic amine content of pork products cooked by different methods and to varying degrees of doneness

Heterocyclic amines (HCAs) are known mutagens and animal carcinogens produced in meats cooked at high temperature. As pork is the second most frequently consumed meat in the United States, five predominant HCAs [2-amino-3-methylimidazo[4,5-f]quinoline (IQ), 2-amino-3,4-dimethylimidazo[4,5-f]quinoline (MeIQ), 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx), 2-amino-3,4,8-trimethylimidazo[4.5-f]quinoxaline (DiMeIQx) and 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP)] were measured in various pork products, cooked by different techniques and to varying doneness levels. Pork chops and ham slices were pan-fried and oven-broiled; bacon was pan-fried, oven-broiled or microwaved; hot dogs were pan-fried, oven-broiled, grilled/barbecued or boiled; sausage links and patties were pan-fried. All the products were cooked to three levels of doneness: just until done, well done or very well done. HCA type and level varied substantially by pork product, cooking method and doneness level. The highest PhIP levels were found in well done and very well done oven-broiled bacon; for very well done 30.3 and 4.0 ng per gram of meat of PhIP and MeIQx, respectively. Pan-fried very well done sausage patties contained 5.4 ng of MeIQx per gram of meat, while sausage links contained 1.3 ng per gram of meat. MeIQx was formed in well done and very well done pan-fried but not broiled pork chops. Hot dogs or ham slices had low or undetectable levels of HCAs. These results demonstrate that epidemiological studies investigating the relationship between HCA intake and cancer risk need to incorporate type of meat, cooking method and degree of doneness/surface browning into questions to assess adequately an individual's HCA exposure.

Analysis of cooked muscle meats for heterocyclic aromatic amine carcinogens

A number of related heterocyclic amines that are mutagenic in bacterial test systems and carcinogenic in animals are formed during the cooking of food. The most commonly reported and abundant compounds are PhIP, MeIQx, DiMeIQx, IQ and A alpha C. Using analysis by solid-phase extraction and HPLC, amounts found in foods range from less than one ng/g for products from fast-food restaurants, up to 14 ng/g in commercially cooked products and over 300 ng/g for well done flame-grilled chicken breast meat. Interestingly, marinating meat for 4 h greatly reduces the amount of PhIP produced during cooking, but not MeIQx. Comparing mutagenic activity in meat samples to the mutagenic activity accounted for by the known heterocyclic amines shows that most samples have activity that cannot be accounted for by the aromatic amines we can currently identify. This suggests that additional compounds are present in these foods and need to be investigated, particularly those grilled over open flames.

Heterocyclic aromatic amine content in pre-processed meat cuts produced in Canada

In an ongoing survey, the presence of heterocyclic aromatic amines (HAAs) was determined in processed, ready-to-eat meat products sold as 'meat cuts'. HAAs are a group of recently recognized mutagenic/carcinogenic contaminants in foods that are produced during the heat processing of meat. 16 samples of meat cuts (e.g. turkey breast, salami, chicken loaf, cooked ham, all beef meat, pepperoni, etc.), randomly purchased from supermarkets and specialty food stores in the Ottawa area, were analysed for the presence of eight HAAs. The isolation of HAAs was based on sequential liquid-liquid extraction procedures of the samples at both acidic and basic pH values. The mutagenic activity of these samples was determined using the Ames/Salmonella microsome assay with the strain TA98 plus rat liver S-9 metabolic activation. The mutagenicity of these samples ranged from undetectable to slightly active. The highest mutagenic activity, 141 induced revertants/g, was found in a smoked turkey breast sample. 11 samples were not mutagenic, including two that indicated a tendency for inhibition of the spontaneous revertants. The remaining four samples exhibited very low mutagenic activity. For chemical analysis, the extracts were purified with two solid phase extraction cartridges. Quantitative analysis was performed by using liquid chromatography for separation and mass spectrometry for detection. With the exception of trace amounts (0.4 ng/g) of 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx) in the sample with highest mutagenic activity, the chemical analysis did not detect the presence of any of the eight most frequently found HAAs in fried or broiled meat products. These data suggest that consumption of meat cuts does not present a serious health risk from HAA-type contaminants.

Effect of commercial marinades on the mutagenic activity, sensory quality and amount of heterocyclic amines in chicken grilled under different conditions

The effect of processing conditions on the mutagenic activity and sensory quality of everyday food was studied by investigating grilled chicken samples seasoned with four different marinades and grilled at temperatures of about 110, 170 and 220 degrees C. The amounts of the heterocyclic amines 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline, 2-amino-3,4,8-trimethylimidazo[4,5-f]quinoxaline and 2-amino-1-methyl-6-phenylimidazo[4,5,-b]pyridine were determined only in samples grilled at 220 degrees C, using a gas chromatography-mass spectrometry technique with negative-ion chemical ionization. Sensory quality was determined using the extended ranking test method and the mutagenic activity using the Ames Salmonella assay. At 220 degrees C one of the marinades decreased the mutagenic activity in the chicken samples compared with the unseasoned control or samples treated with the other marinades. Great variations, without any clear correlation with mutagenicity, were observed in the amounts of heterocyclic amines between chicken samples treated with the same or different marinades. At the grilling temperatures of 170 degrees C and 110 degrees C the mutagenic activities of the chicken samples were lower or they were non-mutagenic. There was no correlation between mutagenic activity and sensory quality of the products. The samples with high mutagenic activity were ranked to be as good as the samples with lower or no mutagenicity. The results show that it is possible to prepare grilled products with reduced mutagenicity without compromising their sensory quality. It was also evident that marinades can have a reducing effect on the mutagenicity of grilled chicken. Variation observed in the amounts of heterocyclic amines between equivalent products makes it difficult to estimate their concentration in everyday foods.

The effect of teas on the in vitro mutagenic potential of heterocyclic aromatic amines

Water extracts of eight brands (five types: 'green', 'black', 'oolong', decaffeinated and instant) of common teas (derived from Camellia sinensis) and infusions of six randomly selected herbal teas were examined for inhibitory or potentiating effects on the mutagenicity of eight heterocyclic aromatic amines (HAA) using the Ames Salmonella typhimurium TA98 and S-9 assay. HAA, produced in foods during regular heat processing of meat, exhibit mutagenic/carcinogenic activities. Tea extracts from C. sinensis displayed very potent antimutagenic effects against most HAA: total or substantial inhibition of mutagenic activity of the eight HAA was obtained with extracts equivalent to 50 mg tea leaves/plate (mgEq) and potent inhibition was frequently achieved even with 10 mgEq/plate. Decaffeinated tea produced the same effect as observed for 'regular' teas. However, lower concentrations of some tea extracts enhanced mutagenic activity of 2-amino-3,4,7,8-tetramethyl-3H-imidazo[4,5-f]quinoxaline (4,7,8-TriMeIQx) and 3-amino-1-methyl-5H-pyrido[4,3-b]indole (Trp-P-2). Herbal tea extracts displayed variable effects on the mutagenicity of different HAA. While some extracts had no effect, others exhibited a moderate inhibitory effect on the mutagenicity of IQ-type HAA. In contrast to common tea, herbal teas showed substantial potentiating effects on the mutagenicity of several HAA, especially Trp-P-2 and 4,7,8-TriMeIQx.