Instruct: Given a question, retrieve relevant passages that answer the question.
Query: Maggot Meat Spray
OBJECTIVE: To evaluate a novel coconut-derived emulsion (CDE) shampoo against head lice infestation in children. DESIGN: A school trial in which pupils were treated on days 0 and 7 and checked on days 8 and 15 and a family trial where product was applied by parents three times in 2 weeks or used as a cosmetic shampoo and checked on days 14 and days 70. SETTING: UK schools in Bristol and Western-super-Mare and families in Northern Somerset. MAIN OUTCOME MEASURE: Numbers of children free from infestation after treatment. RESULTS: In the school trial, percentage cures at day 8 were 14% (permethrin, n=7) and 61% (CDE, n=37). In the family trial where all family members were treated, cure rate was 96% (n=28), and if the shampoo was subsequently used as a cosmetic shampoo, only 1 of 12 children became re-infested after 10 weeks. CONCLUSION: CDE shampoo is a novel effective method of controlling head lice and used after treatment as a cosmetic shampoo can aid in the reduction of re-infestation.
In contrast to the use of hormonal doping agents in sports to enhance the performance of athletes, in the livestock industry hormonal growth promoters ("anabolics") are used to increase the production of muscle meat. This leads to international disputes about the safety of meat originating from animals treated with such anabolics.As a consequence of the total ban in the EU of all hormonal active growth promoters ("hormones") in livestock production, in contrast to their legal use [e.g. of five such hormones (17beta-estradiol, testosterone, progesterone, trenbolone and zeranol) as small solid ear implants and two hormones as feed additives for feedlot heifers (melengestrol acetate) and for swine (ractopamine) in the USA], the regulatory controls also differ sharply between the EU and the USA.In the EU the treatment of slaughter animals is the regulatory offence that has to be controlled in inspection programs. In the USA testing for compliance of a regulatory maximum residue level in the edible product (muscle, fat, liver or kidney) is the purpose of the inspection program (if any).The EU inspection programs focus on sample materials that are more suitable for testing for banned substances, especially if the animals are still on the farm, such as urine and feces or hair. In the case of slaughtered animals, the more favored sample materials are bile, blood, eyes and sometimes liver. Only in rare occasions is muscle meat sampled. This happens only in the case of import controls or in monitoring programs of meat sampled in butcher shops or supermarkets.As a result, data on hormone concentrations in muscle meat samples from the EU market are very rare and are obtained in most cases from small programs on an ad hoc basis. EU data for natural hormones in meat are even rarer because of the absence of "legal natural levels" for these hormones in compliance testing. With the exception of samples from the application sites - in the EU the site of injection of liquid hormone preparations or the site of application of "pour on" preparations - the hormone concentrations observed in meat samples of illegally treated animals are typically in the range of a few micrograms per kilogram (ppb) down to a few tenths of a microgram per kilogram. In the EU dozens of illegal hormones are used and the number of active compounds is still expanding. Besides estrogenic, androgenic and progestagenic compounds also thyreostatic, corticosteroidal and beta-adrenergic compounds are used alone or in "smart" combinations.An overview is given of the compounds identified on the EU black market. An estimate is also given of the probability of consumption in the EU of "highly" contaminated meat from the application sites in cattle. Finally some data are presented on the concentration of estradiol in bovine meat from animals treated and not treated with hormone implants. These data are compared with the recent findings for estradiol concentrations in hen's eggs. From this comparison, the preliminary conclusion is that hen's eggs are the major source of 17alpha- and 17beta-estradiol in the consumer's daily "normal" diet.
Over the past 10years there has been ongoing development of curing processes with natural ingredients designed to meet consumer demand and regulatory requirements for natural and organic processed meats. Initially, these processes utilized celery concentrates with a high nitrate content combined with a nitrate-reducing starter culture. Subsequent advances included celery concentrates with the nitrate converted to nitrite by suppliers. Further, as questions developed concerning reduced concentration of preservatives and the microbiological safety of these processed meats, additional advances have resulted in a wide variety of ingredients and processes designed to provide supplementary antimicrobial effects for improved product safety. Copyright © 2012 Elsevier Ltd. All rights reserved.
Microwave-assisted extraction (MAE) and dispersive liquid-liquid microextraction (DLLME) coupled with gas chromatography-mass spectrometry (GC-MS) were evaluated for use in the extraction and preconcentration of volatile nitrosamines in meat products. Parameters affecting MAE, such as the extraction solvent used, and DLLME, including the nature and volume of the extracting and disperser solvents, extraction time, salt addition and centrifugation time, were optimized. In the MAE method, 0.25g of sample mass was extracted in 10mL NaOH (0.05M) in a closed-vessel system. For DLLME, 1.5mL of methanol (disperser solvent) containing 20μL of carbon tetrachloride (extraction solvent) was rapidly injected by syringe into 5mL of the sample extract solution (previously adjusted to pH 6), thereby forming a cloudy solution. Phase separation was performed by centrifugation, and a volume of 3μL of the sedimented phase was analyzed by GC-MS. The enrichment factors provided by DLLME varied from 220 to 342 for N-nitrosodiethylamine and N-nitrosopiperidine, respectively. The matrix effect was evaluated for different samples, and it was concluded that sample quantification can be carried out by aqueous calibration. Under the optimized conditions, detection limits ranged from 0.003 to 0.014ngmL(-1) for NPIP and NMEA, respectively (0.12-0.56ngg(-1) in the meat products). Copyright © 2011 Elsevier B.V. All rights reserved.
Monosodium glutamate (MSG) is a salt form of a non-essential amino acid commonly used as a food additive for its unique flavour enhancing qualities. Since the first description of the 'Monosodium glutamate symptom complex', originally described in 1968 as the 'Chinese restaurant syndrome', a number of anecdotal reports and small clinical studies of variable quality have attributed a variety of symptoms to the dietary ingestion of MSG. Descriptions of MSG-induced asthma, urticaria, angio-oedema, and rhinitis have prompted some to suggest that MSG should be an aetiologic consideration in patients presenting with these conditions. This review prevents a critical review of the available literature related to the possible role of MSG in the so-called 'Chinese restaurant syndrome' and in eliciting asthmatic bronchospasm, urticaria, angio-oedema, and rhinitis. Despite concerns raised by early reports, decades of research have failed to demonstrate a clear and consistent relationship between MSG ingestion and the development of these conditions.
The inhibitory effect of Old Coke, caffeine-free New Coke, New Coke, Diet Coke and Pepsi-Cola on human sperm motility was studied with a trans-membrane migration method. None of them could decrease sperm motility to less than 70% of control within one hour. A previous study which claimed a marked variation of spermicidal potencies among different formulations of Coca-Cola could not be confirmed. Even if cola has a spermicidal effect, its potency is relatively weak as compared with other well-known spermicidal agents.
OBJECTIVE: The purposes of this study were to examine milk allergic patients to determine concomitant reactivity between milk, beef, pork and cat and dog dander and other common inhalant allergens. METHODS: 19 patients were selected according to their Immuno-CAP results, which had increased Ig-E levels against milk, pork or beef. Patients were also tested against Johnson grass, short ragweed, cat/dog dander and d. farina. RESULTS: Pearson's test revealed strong correlation between beef and pork, beef and milk, pork and milk Ig-E counts (consecutively r2 = 0.89, r2 = 0.81, r2 = 0.60 and p < 0.01. All cat allergic patients also appeared to be allergic to either beef/pork meat or milk. The correlation between pork and dog dander Ig-E counts was also significant (r2 = 0.38, p < 0.01). No correlation detected between milk-meat-pet and grass-weed-dust allergies. DISCUSSION AND CONCLUSION: Patients who are known to have pet allergies may need to be screened for meat and milk allergy. Milk allergic patients may also need to avoid cows and pork meat.
Transglutaminase is an enzyme that can be used to cross-link pieces of meat, fish or meat products. The resulting product gives the optical impression of an intact chunk of meat. The usage of transglutaminase as a food additive is permitted in some countries. However, its utilisation has to be declared to ensure transparency for consumers. This paper describes two orthogonal analytical methods suited for the detection of technological relevant transglutaminase concentrations (around 25 mg pure enzyme in 1 kg of product) in meat and meat products. The mass spectrometry-based approach relies on a previous digestion with Achromobacter lyticus protease and LC-MS/MS separation and detection. Sufficient selectivity was obtained by monitoring four different peptides. The orthogonal (complementary and independent), ELISA-based approach relies on two commercially available bacterial transglutaminase-specific antibodies, combined to a sandwich ELISA. The two methods were tested by analysing some 60 samples obtained from the market.
A low-grade inflammatory response ('metaflammation') has been found to be associated with certain chronic diseases. Proposed inducers of this have been aspects of the modern lifestyle, including newly introduced foods. Plasma TAG, and the inflammatory cytokines C-reactive protein (CRP), TNF-alpha and IL-6 were compared in a randomised, cross-over trial using ten healthy subjects before and after eating 100 g of kangaroo, or a 'new' form of hybridised beef (wagyu) separated by about 1 week. Postprandial levels for 1 and 2 h of TAG, IL-6 and TNF-alpha were significantly higher after eating wagyu compared with kangaroo (P = 0.002 for TAG at 1 h, P < 0.001 at 2 h; P < 0.001 for IL-6 and TNF-alpha at 1 and 2 h). CRP was significantly higher 1 h postprandially after wagyu (P = 0.011) and non-significantly higher 2 h postprandially (P = 0.090). We conclude that the metaflammatory reaction to ingestion of a 'new' form of hybridised beef (wagyu) is indicative of a low-grade, systemic, immune reaction when compared with lean game meat (kangaroo). Further studies using isoenergetic intake and isolating fatty acid components of meats are proposed.
The effects of three different meat-containing breakfast meals (pork, beef or chicken) on acute satiety and appetite regulatory hormones were compared using a within-subjects study design. Thirty fasting non-smoking pre-menopausal women attended a research centre on three test days to consume, a meat-containing meal matched in energy (kJ) and protein content, palatability, and appearance. No difference was found between meat groups for either energy intake or macronutrient profile of food consumed at a subsequent ad libitum buffet lunch, or over the rest of the day. Visual Analogue Scale (VAS) ratings for hunger and satiety over an 180 min period did not differ between test meals. After consumption of the test meals, a significant difference was found in PYY response between pork and chicken meals (P=0.027) but not for levels of CCK, ghrelin, insulin or glucose. This study positions pork, beef, and chicken as equal in their effect on satiety and release of appetite-related intestinal hormones and of insulin. Copyright © 2010 Elsevier Ltd. All rights reserved.
Background The recent increased interest in consuming green vegetable sprouts has been tempered by the fact that fresh sprouts can in some cases be vehicles for food-borne illnesses. They must be grown according to proper conditions of sanitation and handled as a food product rather than as an agricultural commodity. When sprouts are grown in accordance with the criteria proposed from within the sprout industry, developed by regulatory agencies, and adhered to by many sprouters, green sprouts can be produced with very low risk. Contamination may occur when these guidelines are not followed. Methods A one year program of microbial hold-and-release testing, conducted in concert with strict seed and facility cleaning procedures by 13 U.S. broccoli sprout growers was evaluated. Microbial contamination tests were performed on 6839 drums of sprouts, equivalent to about 5 million consumer packages of fresh green sprouts. Results Only 24 (0.75%) of the 3191 sprout samples gave an initial positive test for Escherichia coli O157:H7 or Salmonella spp., and when re-tested, 3 drums again tested positive. Composite testing (e.g., pooling up to 7 drums for pathogen testing) was equally sensitive to single drum testing. Conclusion By using a "test-and-re-test" protocol, growers were able to minimize crop destruction. By pooling drums for testing, they were also able to reduce testing costs which now represent a substantial portion of the costs associated with sprout growing. The test-and-hold scheme described herein allowed those few batches of contaminated sprouts to be found prior to packaging and shipping. These events were isolated, and only safe sprouts entered the food supply.
Polybrominated diphenyl ether (PBDE) body burdens in the general U.S. population have been linked to the consumption of red meat and poultry. Exposure estimates have also indicated that meat products are a major contributor to PBDE dietary intake. To establish solid estimates of PBDE concentrations in domestic meat and poultry, samples from two statistically designed surveys of U.S. meat and poultry were analyzed for PBDEs. The two surveys were conducted in 2002-2003 and 2007-2008, between which times the manufacturing of penta-BDE and octa-BDE formulations had ceased in the United States (December 2004). Thus, the data provided an opportunity to observe prevalence and concentration trends that may have occurred during this time frame and to compare the mean PBDE levels among the meat and poultry industries. On the basis of composite samples, the average sum of the seven most prevalent PBDEs (BDE-28, -47, -99, -100, -153, -154, and -183) decreased by >60% from 1.95 ng/g lipid in 2002-2003 to 0.72 ng/g lipid in 2007-2008 for meat and poultry. PBDEs measured in individual samples in 2008 showed that beef samples had the lowest PBDE levels followed by hogs and chickens and then by turkeys. The PBDE congener pattern was the same for both surveys and resembled the penta-BDE formulation with BDE-47 and -99 accounting for 30 and 40% of the total, respectively. On the basis of the data from the two surveys, it appears that PBDE levels in U.S. meat and poultry have declined since manufacturing ceased; however, exposure pathways of PBDEs to livestock are still not known.
The effect of a mixed Western, high meat diet or a nonmeat diet on the intestinal bacterial beta-glucuronidase activity was studied in human volunteers. This enzyme was significantly higher in stools of subjects on a high meat diet as compared to the nonmeat regimen. Thus, intestinal flora of subjects on a high meat diet was more able to hydrolyze glucuronide conjugates than that of individuals on a nonmeat diet. This, in turn, may raise the amount of substances, such as carcinogens, within the colonic lumen.
Axillary body odor is individually specific and potentially a rich source of information about its producer. Odor individuality partly results from genetic individuality, but the influence of ecological factors such as eating habits are another main source of odor variability. However, we know very little about how particular dietary components shape our body odor. Here we tested the effect of red meat consumption on body odor attractiveness. We used a balanced within-subject experimental design. Seventeen male odor donors were on "meat" or "nonmeat" diet for 2 weeks wearing axillary pads to collect body odor during the final 24 h of the diet. Fresh odor samples were assessed for their pleasantness, attractiveness, masculinity, and intensity by 30 women not using hormonal contraceptives. We repeated the same procedure a month later with the same odor donors, each on the opposite diet than before. Results of repeated measures analysis of variance showed that the odor of donors when on the nonmeat diet was judged as significantly more attractive, more pleasant, and less intense. This suggests that red meat consumption has a negative impact on perceived body odor hedonicity.
The co-occurrence of fish MeHg and omega-3 fatty acids in wild species can indeed be optimized by choosing certain species. Farmed finfish and shellfish that are fed fish-meal, however, can bioconcentrate both MeHg (in muscle) and organohalogen pollutants passed on in the fat components [Dorea, J.G., 2006. Fish meal in animal feed and human exposure to persistent bioaccumulative and toxic substances. J. Food Prot. 69, 2777-2785); when fish-meal is used to feed farm animals it may offer the worst of both worlds: saturated fat (with organohalogen pollutants) and MeHg. It is time to address the dietary sources of Hg derived from animals raised on fish-meal that may contribute to increase tissue Hg concentrations.
Natural and organic food regulations preclude the use of sodium nitrite/nitrate and other antimicrobials for processed meat products. Consequently, processors have begun to use natural nitrate/nitrite sources, such as celery juice/powder, sea salt, and turbinado sugar, to manufacture natural and organic products with cured meat characteristics but without sodium nitrite. The objective of this study was to compare physio-chemical characteristics that affect Clostridium perfringens and Listeria monocytogenes growth in naturally cured and traditionally cured commercial frankfurters, hams, and bacon. Correlations of specific product characteristics to pathogen growth varied between products and pathogens, though water activity, salt concentration, and product composition (moisture, protein and fat) were common intrinsic factors correlated to pathogen growth across products. Other frequently correlated traits were related to curing reactions such as % cured pigment. Residual nitrite and nitrate were significantly correlated to C. perfringens growth but only for the ham products. Copyright © 2012 Elsevier Ltd. All rights reserved.
Reports have documented colonization of swine in Europe, North America and more recently in China with livestock-associated methicillin-resistant Staphylococcus aureus (LA-MRSA). Contamination of pig farmers, veterinarians and abattoir workers with these strains has been observed. However, although contamination levels of 10% of retail pork were reported from the Netherlands and Canada, there are limited data of contamination rates of workers handling raw meat. We investigated the rates of MRSA contamination of local butchers working in wet markets, where recently slaughtered pigs are cut up. Nasal swabs collected from 300 pork butchers at markets throughout Hong Kong were enriched in brain heart infusion broth with 5% salt and cultured on MRSASelect(®) . Isolates were confirmed as Staphylococcus aureus and susceptibility testing performed. The presence of mecA was confirmed, SCCmec and spa type determined and relatedness investigated by PFGE. Subjects completed a questionnaire on MRSA carriage risk factors. Seventeen samples (5.6%) yielded MRSA, 15 harbouring SCCmec IVb. Ten strains were t899 (CC9), previously reported from local pig carcasses. Five strains were healthcare associated: SCCmec type II, t701(CC6), colonizing two subjects at the same establishment, and single isolates of t008 (CC8), t002 (CC5) and t123 (CC45). The remaining isolates were t359 (CC97), previously reported from buffaloes, and t375 (CC5), reported from bovine milk. None of these butchers reported recent hospitalization or a healthcare worker in the family. Two had recently received antibiotics, one for a skin infection. Four reported wound infections within the last year. All were exposed to meat for >9 h per day. Carriage of MRSA was higher in butchers than in the general community. Although five strains were probably of healthcare origin, the high incidence of t899 (CC9) suggests that cross-contamination from pork occurs frequently. Washing of hands after touching raw pork is advised. © 2012 Blackwell Verlag GmbH.
It was previously reported that a methanol extract of Gloiopeltis furcata (MEGF), a kind of edible seaweed, inhibited the growth of several human cancer cell lines. In the present study, the effect of MEGF on the growth of human hepatocarcinoma HepG2 cells and its effect on the cyclooxygenases (COXs) expression were investigated. MEGF markedly reduced the viability of HepG2 cells and induced the G2/M arrest of the cell cycle in a concentration dependent manner. These effects were associated with the down-regulation of cyclin A, up-regulation of cyclin-dependent kinase (Cdk) inhibitor p21 (WAF1/CIP1) and dephosphorylation of Cdc25C. Furthermore, it was found that MEGF decreased the levels of COX-2 mRNA and protein expression without significant changes in the levels of COX-1, which was correlated with a decrease in prostaglandin E(2) (PGE(2)) synthesis. These findings indicate that MEGF may have a possible therapeutic potential in hepatoma cancer patients.
Blood components, especially hemoglobin, are powerful promoters of lipid oxidation and may decrease the shelf life of meat products. Therefore, this study examined different slaughter techniques to determine their effects on pH (24 h), color (L*a*b* values at 24 h), lipid oxidation, residual hemoglobin concentration (24 h), and sensory evaluation (d 1 and 4 postmortem; PM) in broiler breast fillets. The treatments included 1) CO(2) slaughter and not bled, 2) no stunning and bled, 3) electrical stunning (ES) and bled, 4) CO(2) stunning and bled, and 5) ES and decapitation. The birds were conventionally processed, and analyses were performed at 24 h PM except residual hemoglobin for which the samples were frozen (-80 degrees C) until analyses ( < 2 mo). There were no significant differences in pH or b* values at 24 h PM among any of the treatments. L* values were significantly higher, indicating lighter fillets in the ES and decapitated birds compared with the darker fillets from the CO(2) stunned and bled birds. The CO(2) slaughter and not bled birds had significantly higher a* values, indicating more red color, when compared with the ES and bled and decapitated birds. There were no significant differences in the residual hemoglobin contents in the broiler breast muscle when comparing all of the treatments except CO(2) slaughter and not bled, which was significantly (around 15%) greater. Overall TBA-reactive substances (TBARS; raw, cooked at 24 h, and cooked at 72 h PM) indicated that ES and bled birds had the lowest TBARS when compared with the remaining treatments. Consumer panels detected increased aroma (chicken meaty and warmed-over aromas) and flavor (chicken meaty and warmed-over flavors) in not bled samples at 24 h PM. By 72 h PM, however, there were no significant differences in aroma or flavor. Therefore, different slaughter and bleeding method may affect color and sensory properties of the broiler breast fillets, and the ES and decapitation method had the most favorable results for sensory quality.
Response surface methodology was used to study the effect of flaxseed flour (FS) and tomato paste (TP) addition, from 0 to 10% and 0 to 20% respectively, on beef patty quality characteristics. The assessed quality characteristics were color (L, a, and b), pH and texture profile analysis (TPA). Also, sensory analysis was performed for the assessment of color, juiciness, firmness, and general acceptance. FS addition reduced L and a values and decreased weight loss of cooked products (P<0.05). An opposite effect was observed when TP was added (P<0.05). All TPA parameters decreased when percentages of FS and TP were increased in the formulation of beef patties. Furthermore, FS and TP addition adversely affected the sensory characteristics of the cooked product (P<0.05); nevertheless, all sensory characteristics evaluated had an acceptable score (>5.6). Thus FS and TP are ingredients that can be used in beef patty preparation. Copyright © 2014 Elsevier Ltd. All rights reserved.
The influence of protein oxidation, as measured by the dinitrophenylhydrazine (DNPH) method, on colour and texture changes during chill storage (2 degrees C, 12days) of cooked burger patties was studied. Extracts from arbutus-berries (Arbutus unedoL., AU), common hawthorns (Crataegus monogynaL., CM), dog roses (Rosa caninaL., RC) and elm-leaf blackberries (Rubus ulmifoliusSchott., RU) were prepared, added to burger patties (3% of total weight) and evaluated as inhibitors of protein oxidation and colour and texture changes. Negative (no added extract, C) and positive control (added quercetin; 230mg/kg, Q) groups were also considered. The significant increase of protein carbonyls during chill storage of control burger patties reflect the intense oxidative degradation of the muscle proteins. Concomitantly, an intense loss of redness and increase of hardness was found to take place in burger patties throughout refrigerated storage. Most fruit extracts as well as Q significantly reduced the formation of protein carbonyls and inhibited colour and texture deterioration during chill storage. Likely mechanisms through which protein oxidation could play a major role on colour and texture changes during chill storage of burger patties are discussed. Amongst the extracts, RC was most suitable for use as a functional ingredient in processed meats since it enhanced oxidative stability, colour and texture properties of burger patties with no apparent drawbacks. Copyright 2010 Elsevier Ltd. All rights reserved.
Airborne cooking by-products from frying beef (hamburgers), pork (bacon strips) and soybean-based food (tempeh burgers) were collected, extracted, tested for mutagenicity and chemically analysed. The fumes generated by frying pork and beef were mutagenic, with 4900 and 1300 revertants/g of food cooked, respectively. No mutagenicity was detected in fumes from frying tempeh burgers. Bacon fried to a well-done but non-charred state was eight times more mutagenic in a microsuspension Ames/Salmonella test (TA98 with S-9) than hamburgers and about 350 times more mutagenic than tempeh burgers. Among food samples cooked to a well-done, non-charred state, bacon strips had almost 15-fold more mass (109.5 ng/g) than that of the beef, whereas no heterocyclic amine (HCA) was detected in the fried tempeh burgers. 2-Amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) was the most abundant HCA, followed by 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx) and 2-amino-3,4,8-trimethylimidazo[4,5-f]quinoxaline (DiMeIQx). No 2-amino-9H-pyrido[2,3-b]indole (A alpha C) was detected in the food samples fried at about 200 degrees C, although it was present in the collected airborne products. The total amounts of HCAs in the smoke condensates were 3 ng/g from fried bacon, 0.37 ng/g from fried beef and 0.177 ng/g from fried soy-based food. This study indicates that cooks are potentially exposed to relatively high levels of airborne mutagens and carcinogens and that long-term sampling inside restaurants and kitchens may be warranted in order to assess the potential risk of prolonged exposure.
The association between cured and broiled meat consumption by the mother during pregnancy and by the child was examined in relation to childhood cancer. Five meat groups (ham, bacon, or sausage; hot dogs; hamburgers; bologna, pastrami, corned beef, salami, or lunch meat; charcoal broiled foods) were assessed. Exposures among 234 cancer cases (including 56 acute lymphocytic leukemia [ALL], 45 brain tumor) and 206 controls selected by random-digit dialing in the Denver, Colorado (United States) standard metropolitan statistical area were compared, with adjustment for confounders. Maternal hot-dog consumption of one or more times per week was associated with childhood brain tumors (odds ratio [OR] = 2.3, 95 percent confidence interval [CI] = 1.0-5.4). Among children, eating hamburgers one or more times per week was associated with risk of ALL (OR = 2.0, CI = 0.9-4.6) and eating hot dogs one or more times per week was associated with brain tumors (OR = 2.1, CI = 0.7-6.1). Among children, the combination of no vitamins and eating meats was associated more strongly with both ALL and brain cancer than either no vitamins or meat consumption alone, producing ORs of two to seven. The results linking hot dogs and brain tumors (replicating an earlier study) and the apparent synergism between no vitamins and meat consumption suggest a possible adverse effect of dietary nitrites and nitrosamines.
The effect of dietary components on the levels of nitrosoproline ( NPRO ) excreted over a 24 h period in the urine was examined in volunteers ingesting known amounts of various food products. The ingestion of nitrite-preserved meats (85-170 g per meal), including canned, rolled or Yunnan ham, cured pork, luncheon meat, and various Chinese and European-style sausages, led to urinary NPRO excretion levels ranging from 2.5 to 78.5 micrograms/24 h, whereas the consumption of non-preserved meat and fish products, including chicken, herring, salmon, shrimp, ground beef (hamburger), pork chops and beef liver, led to relatively low NPRO excretion levels, ranging from 0.0 to 0.8 micrograms/24 h. The urinary NPRO levels of 22 vegetarians and 14 lacto-vegetarians averaged 0.8 and 1.4 micrograms/24 h, respectively. A change from a nitrite-preserved meat diet to a vegetarian diet was accompanied by an approximately six-fold reduction in urinary NPRO levels; however, these remained above control levels for at least 3 days following the dietary change. The relatively high NPRO levels following the ingestion of nitrite-preserved meats could not be reduced by nitrite-trapping chemicals, including ascorbic acid, ferulic acid, caffeic acid, or phenolic-containing mixtures such as coffee and tea, which were effective in suppressing endogenous NPRO formation following the intake of nitrate and proline. The high urinary NPRO levels after ingestion of preserved meat products appear to be due to the consumption of preformed NPRO . An understanding of the relative contribution of preformed and endogenously formed nitrosamines appears to be essential when designing dietary intervention programmes.
BACKGROUND: Hydrogen sulfide is a luminally acting, bacterially derived cell poison that has been implicated in ulcerative colitis. Sulfide generation in the colon is probably driven by dietary components such as sulfur-containing amino acids (SAAs) and inorganic sulfur (eg, sulfite). OBJECTIVE: We assessed the contribution of SAAs from meat to sulfide production by intestinal bacteria with use of both a model culture system in vitro and an in vivo human feeding study. DESIGN: Five healthy men were housed in a metabolic suite and fed a sequence of 5 diets for 10 d each. Meat intake ranged from 0 g/d with a vegetarian diet to 600 g/d with a high-meat diet. Fecal sulfide and urinary sulfate were measured in samples collected on days 9 and 10 of each diet period. Additionally, 5 or 10 g bovine serum albumin or casein/L was added to batch cultures inoculated with feces from 4 healthy volunteers. Concentrations of sulfide, ammonia, and Lowry-reactive substances were measured over 48 h. RESULTS: Mean (+/-SEM) fecal sulfide concentrations ranged from 0.22 +/- 0.02 mmol/kg with the 0-g/d diet to 3.38 +/- 0.31 mmol/kg with the 600-g/d diet and were significantly related to meat intake (P: < 0.001). Sulfide formation in fecal batch cultures supplemented with both bovine serum albumin and casein correlated with protein digestion, as measured by the disappearance of Lowry-reactive substances and the appearance of ammonia. CONCLUSION: Dietary protein from meat is an important substrate for sulfide generation by bacteria in the human large intestine.