RESUMEN
Attenuated Total Reflectance-Fourier Transform Infrared spectroscopy (ATR-FTIR), in combination with chemometrics, was explored as a rapid method of detecting sugar adulteration in coconut water. In a simulated experiment, coconut water was substituted with binary sugars, mixed sugars, and high fructose corn syrup and discriminated using the fingerprint infrared band region between 1200 and 950 cm-1. Principal component analysis (PCA) performed on data pre-processed by the Savitzky-Golay smoothing and gap-segment derivative, revealed data clusters discernible by the type and level of substituted sugars, enabling visual diagnosis of the similarity and anomalous features in the dataset. Statistical performance metrics following a cross-validated partial least square (PLS) regression indicated the prediction of adulterant sugars at single-digit percent substitutions. A parallel exploratory analysis of 31 different commercial coconut water samples showed a distinct PCA clustering for samples bearing the label "added sugar", suggesting the potential use of the methods to screening samples for undeclared sugar additions.
Asunto(s)
Cocos/química , Jugos de Frutas y Vegetales/análisis , Espectroscopía Infrarroja por Transformada de Fourier/métodos , Análisis por Conglomerados , Cocos/metabolismo , Análisis de los Mínimos Cuadrados , Análisis de Componente Principal , Azúcares/análisisRESUMEN
This article covers challenges and trends in the determination of some major food chemical contaminants and allergens, which-among others-are being monitored by Health Canada's Food Directorate and for which background levels in food and human exposure are being analyzed and calculated. Eleven different contaminants/contaminant groups and allergens have been selected for detailed discussion in this paper. They occur in foods as a result of: use as a food additive or ingredient; processing-induced reactions; food packaging migration; deliberate adulteration; and/or presence as a chemical contaminant or natural toxin in the environment. Examples include acrylamide as a food-processing-induced contaminant, bisphenol A as a food packaging-derived chemical, melamine and related compounds as food adulterants and persistent organic pollutants, and perchlorate as an environmental contaminant. Ochratoxin A, fumonisins, and paralytic shellfish poisoning toxins are examples of naturally occurring toxins whereas sulfites, peanuts, and milk exemplify common allergenic food additives/ingredients. To deal with the increasing number of sample matrices and analytes of interest, two analytical approaches have become increasingly prevalent. The first has been the development of rapid screening methods for a variety of analytes based on immunochemical techniques, utilizing ELISA or surface plasmon resonance technology. The second is the development of highly sophisticated multi-analyte methods based on liquid chromatography coupled with multiple-stage mass spectrometry for identification and simultaneous quantification of a wide range of contaminants, often with much less requirement for tedious cleanup procedures. Whereas rapid screening methods enable testing of large numbers of samples, the multi analyte mass spectrometric methods enable full quantification with confirmation of the analytes of interest. Both approaches are useful when gathering surveillance data to determine occurrence and background levels of both recognized and newly identified contaminants in foods in order to estimate human daily intake for health risk assessment.
Asunto(s)
Alérgenos/análisis , Análisis de los Alimentos , Contaminación de Alimentos/análisis , Contaminación de Alimentos/prevención & control , Inocuidad de los Alimentos , HumanosRESUMEN
The great blue heron (Ardea herodias) has been used as a bioindicator of the state of the St. Lawrence River (Québec, Canada) since 1996. At 5-year intervals, selected breeding colonies along the River and its estuary are visited to estimate reproductive success and determine levels of contamination. Brominated flame retardants are found in many ecosystems and are increasing in concentration in the Great Lakes, which is the source of much of the water for the St. Lawrence River. In 2001 and 2002, in addition to polychlorinated biphenyls (PCBs) and chlorinated pesticides, the levels of polybrominated diphenyl ethers (PBDEs), polychlorinated bornanes (toxaphene) congeners and non-ortho-substituted PCBs were measured for the first time in pools of great blue heron eggs. The PBDE levels in great blue heron eggs (70-1,377 ng/g wet wt) were comparable to those measured in herring gull (Larus argentatus) eggs from the Great Lakes. Toxaphene was detected in great blue heron eggs at levels comparable to those of other major chlorinated pesticides. Major toxaphene congeners were octachlorobornane P44 and the nonachlorobornane P50. Environ.
Asunto(s)
Aves/metabolismo , Huevos/análisis , Monitoreo del Ambiente/métodos , Éteres Difenilos Halogenados/análisis , Ríos/química , Toxafeno/análisis , Contaminantes Químicos del Agua/análisis , Animales , Bifenilos Policlorados/análisisRESUMEN
Perfluorinated compounds (PFCs) have been detected in humans worldwide and are of health concern. This study measured the concentration of PFCs in composite samples collected for the 1998 Health Canada Total Diet Study and estimated dietary exposure for the Canadian population (older than 12 years of age) using previously collected dietary data (n = 1721). PFCs were detected in 8 samples including processed meats, preprepared foods, and peppers with a range of concentrations from 0.48 to 5.01 ng g(-1) (wet weight). 6:2 fluorotelomer unsaturated carboxylate (FTUCA) was detected in cold cuts at a concentration of 1.26 ng g(-1). Mean daily PFC exposure estimates ranged from 1.5 to 2.5 ng (kg of body weight)(-1). Perfluorinated carboxylates (PFCA C(7)-C(11)) contributed more to PFC exposure than either perfluorooctane sulfonate (PFOS) or FTUCA. Total PFCAs in cakes and cookies, lunchmeats, and green vegetables were the main contributors to dietary exposure, although these exposure levels were below the provisional tolerable daily intake provided by the German Drinking Water Commission. Dietary exposure to total PFCs has not changed over time, although the contribution of PFOS to total PFC exposure may have increased between 1998 and 2004. Further research on the sources of contamination of processed and preprepared foods is required. Dietary exposure to PFCs among Canadians poses minimal health risks based on current toxicological information.
Asunto(s)
Ácidos Alcanesulfónicos/administración & dosificación , Ácidos Carboxílicos/administración & dosificación , Dieta , Exposición a Riesgos Ambientales , Fluorocarburos/administración & dosificación , Restaurantes , Ácidos Alcanesulfónicos/análisis , Canadá , Fluorocarburos/análisis , Análisis de los Alimentos , Humanos , Concentración Máxima AdmisibleRESUMEN
Human exposure to perfluorinated compounds is a worldwide phenomenon; however, routes of human exposure to these compounds have not been well-characterized. Fifty-four solid food composite samples collected as part of the Canadian Total Diet Study (TDS) were analyzed for perfluorocarboxylates and perfluorooctanesulfonate (PFOS) using a methanol extraction liquid chromatography tandem mass spectrometry method. Foods analyzed included fish and seafood, meat, poultry, frozen entrées, fast food, and microwave popcorn collected from 1992 to 2004 and prepared as for consumption. Nine composites contained detectable levels of perfluorinated compounds-four meat-containing, three fish and shellfish, one fast food, and one microwave popcorn. PFOS and perfluorooctanoate (PFOA) were detected the most frequently; concentrations ranged from 0.5 to 4.5 ng/g. The average dietary intake of total perfluorocarboxylates and PFOS for Canadians was estimated to be 250 ng/day, using results from the 2004 TDS composites. A comparison with intakes of perfluorocarboxylates and PFOS via other routes (air, water, dust, treated carpeting, and apparel) suggested that diet is an important source of these compounds. There was a substantial margin of exposure between the toxicological points of reference and the magnitude of dietary intake of perfluorinated compounds for Canadians >/= 12 years old.
Asunto(s)
Ácidos Alcanesulfónicos/análisis , Ácidos Carboxílicos/análisis , Exposición a Riesgos Ambientales , Fluorocarburos/análisis , Contaminación de Alimentos/análisis , Embalaje de Alimentos , Hidrocarburos Fluorados/análisis , Animales , Canadá , Peces , Análisis de los Alimentos , Humanos , Carne/análisis , Alimentos Marinos/análisisRESUMEN
Isomers and metabolites of the organochlorine pesticide chlordane persist in the environment and bioaccumulate in Arctic marine food webs. Rodent studies indicate that there are gender-related differences in trans-nonachlor and oxychlordane metabolism. Thus, comparative tissue depletion studies were undertaken in male and female rats exposed to trans-nonachlor, oxychlordane, or trans-chlordane at 2.5 mg/kg body weight/d by gavage for 28 d followed by two consecutive 28-d depletion periods. None of the test chemicals were overtly toxic at this dose, although increased liver weights in some groups were consistent with microsomal enzyme induction. The metabolite oxychlordane accumulated in tissues from rats exposed to trans-nonachlor and trans-chlordane. Trans-Nonachlor and oxychlordane residue levels were highest in tissues from female rats at each time point; however, trans-chlordane was completely eliminated from males and females by the end of the study. Body burden calculations showed no significant clearance of oxychlordane in females over 56 d postdosing, whereas males lost approximately half their oxychlordane body burden in the same period. For the chiral contaminants oxychlordane and trans-chlordane, tissues from male and female rats were selectively depleted of the (+)-enantiomer; however, there were gender-related differences in enantiomer depletion patterns over time. In general, residue analyses confirmed that gender-related metabolic differences and contaminant structural properties, including chirality, influenced chlordane contaminant elimination from rat tissues. The study points to a need for similar knowledge of gender-related responses in humans in order to provide relevant dietary recommendations for populations exposed to chlordane-related contaminants in foods.
Asunto(s)
Clordano/análogos & derivados , Clordano/metabolismo , Hidrocarburos Clorados/metabolismo , Insecticidas/metabolismo , Animales , Carga Corporal (Radioterapia) , Clordano/farmacocinética , Dieta , Femenino , Cadena Alimentaria , Humanos , Hidrocarburos Clorados/farmacocinética , Insecticidas/farmacocinética , Isomerismo , Masculino , Salud Pública , Ratas , Ratas Sprague-Dawley , Reproducibilidad de los Resultados , Factores SexualesRESUMEN
Geographical distribution of brominated diphenyl ether (BDE) flame retardants in the North American Great Lakes ecosystem in 2000 was determined by analysis of herring gull eggs (13 egg pools) from a network of 15 monitoring colonies scattered throughout the lakes and connecting channels. sigmaBDEs were found at concentrations ranging from 192 to 1,400 microg/kg, mean of 662 +/- 368 microg/kg (wet weight of egg contents). Highest concentrations were found in northern Lake Michigan and Toronto harbor (1,000-1,400 microg/kg) and lowest in Lake Huron and Lake Erie (192-340 microg/kg). The distribution suggested that input from large urban/ industrial areas through air or water emissions contributes local contamination to the herring gull food web in addition to background levels from regional/global transport. The congener composition was similar among sampling sites. Major congeners were BDE-47 (43%), BDE-99 (26%), BDE-100 (13%) BDE-153 (11%), BDE-154 (4%), BDE-183 (2%) and BDE-28 (1%). Temporal trends of BDE contamination, 1981-2000, were established by analysis of archived herring gull eggs (10 egg pools) from colonies in northern Lake Michigan, Saginaw Bay, Lake Huron and eastern Lake Ontario. BDE-47, -99 and -100, and BDE-153, -154 and -183 concentrations were grouped separately for analysis because these two groups had different trends and are primarily associated with the Penta BDE and Octa BDE flame retardant formulations, respectively. SigmaBDE47,99,100 concentrations were 5-12 microg/kg (wet weight) in 1981-1983 and then increased exponentially (p < 0.00001) at all three sites to 400-1,100 microg/kg over the next 17 years. Doubling times were 2.6 years in Lake Michigan, 3.1 years in Lake Huron and 2.8 years in Lake Ontario. SigmaBDE154,153,183 concentrations generally increased but varied in an erratic fashion among sites and decreased as a fraction of sigmaBDE over time. Concentrations of sigmaBDE154,153,183 were 100-200 microg/kg in eggs from all three colonies in 2000. Therefore, most of the dramatic increases in sigmaBDE concentrations observed over the past 20 years in the Great Lakes aquatic ecosystem seem to be connected with the Penta BDE formulation, which is mainly used as a flame retardant in polyurethane foam in North America. If present rates of change continue, concentrations of sigmaBDEs will equal or surpass those of sigmaPCBs in Great Lakes herring gull eggs in 10-15 years.