Aflatoxins (AF) are toxic fungal secondary metabolites and are known mycotoxins pathological to a... more Aflatoxins (AF) are toxic fungal secondary metabolites and are known mycotoxins pathological to animals and humans. Poultry litter is frequently used as a food supplement for ruminants, and when poultry feed contains AF, the litter becomes contaminated as well, thus having an effect on livestock health. This study identified and quantified AF (AFB(1), AFB(2), AFG(1), and AFG(2)) from poultry feed and their recovery, together with their metabolites (AFM(1), AFM(2), AFP(1), and aflatoxicol) in litter. An experiment with 25 Hy-Line W-36 hens, in their second production stage, 121 wk old, was carried out. Hens were distributed in 3 groups placed in individual cages and 1 ration of 250 g of feed was given to each hen daily. Nine hens of the control group were fed with clean feed, without AFB(1); the other 2 experimental groups, with 8 hens each, were fed with 2 AFB(1) concentrations: 30 and 500 microg.kg(-1). The feed was replaced and weighed daily throughout a 7-d period to register the amount of feed consumed by the hens. Litter from each hen was collected, weighed, and dried individually. The chemical analysis of 40 g of each one of the 200 feed and 200 litter samples was chemically extracted and concentrated with immunoaffinity columns for total AF. To quantify AF, calibration curves for each AF were done by HPLC. Feed samples of the 3 groups presented significant difference with AFB(2) and AFG(2), whereas in litter samples, there were significant differences for AFG(2) in the 500 microg.kg(-1) group. Poultry litter had traces of AFM(1), AFM(2), AFP(1), and AFL with no significant differences among treatments. Aflatoxin B(1) prevalence in litter samples can cause damages in livestock because this mycotoxin reduces the digestibility of ruminant feed up to 67%.
Rice is an important cereal but it is often contaminated with aflatoxins (AFs). The purpose of th... more Rice is an important cereal but it is often contaminated with aflatoxins (AFs). The purpose of this study was to identify and quantify AF (B1, B2, G1, and G2) in 67 rice samples cultivated in Mexico and Spain, and from imported crops collected in 2008 and 2009. The methodology was validated, the rice samples were concentrated and purified with immunoaffinity columns and were quantified by high‐pressure liquid chromatography (HPLC). The average total AF (AFt) in the Spanish rice was 37.3 μg/kg, the range was from 1.6 to 1383 μg/kg, the most contaminated samples being from San Juan de Aznalfarache, Sevilla (AFt = 138.6 μg/kg), from Tortosa, Tarragona (AFt = 104.6 μg/kg), and Calasparra, Murcia (AFt = 103.9 μg/kg). The rice imported from France to Spain had AFt of 26.6 μg/kg and from Pakistan AFt of 18.4 μg/kg, showing less AF contamination than the local one. The rice which originated from Mexico contained (AFt = 16.9 μg/kg), and those imported from the United States (AFt = 14.4 μg/kg...
The accuracy of the Content should not be relied upon and should be independently verified with p... more The accuracy of the Content should not be relied upon and should be independently verified with primary sources of information. Taylor and Francis shall not be liable for any losses, actions, claims, proceedings, demands, costs, expenses, damages, and other liabilities whatsoever or howsoever caused arising directly or indirectly in connection with, in relation to or arising out of the use of the Content. This article may be used for research, teaching, and private study purposes. Any substantial or systematic reproduction, redistribution, reselling, loan, sub-licensing, systematic supply, or distribution in any form to anyone is expressly forbidden.
International collaborative follow-up investigation of graduating high school students’ understandings of the nature of scientific inquiry: is progress Being made?, 2021
Understandings of the nature of scientific inquiry (NOSI), as opposed to engaging students in inq... more Understandings of the nature of scientific inquiry (NOSI), as opposed to engaging students in inquiry learning experiences, are included in science education reform documents around the world. However, little is known about what students have learned about NOSI during their pre-college school years. The purpose of this large-scale follow-up international project (i.e. 32 countries and regions, spanning six continents and including 3917 students for the high school sample) was to collect data on what exiting high school students have learned about NOSI. Additionally, the study investigated changes in 12th grade students’ NOSI understandings compared to seventh grade (i.e. 20 countries and regions) students’ understandings from a prior investigation [Lederman et al. (2019). An international collaborative investigation of beginning seventh grade students’ understandings of scientific inquiry: Establishing a baseline. Journal of Research in Science Teaching, 56(4), 486–515. https://doi.org/10.1002/tea.21512]. This study documents and discusses graduating high school students’ understandings and compares their understandings to seventh grade students’ understandings of the same aspects of scientific inquiry for each country. It is important to note that collecting data from each of the 130+ countries globally was not feasible. Similarly, it was not possible to collect data from every region of each country. A concerted effort was made, however, to provide a relatively representative picture of each country and the world.
En esta investigación bibliográfica se plantea la importancia de realizar una investigación tendi... more En esta investigación bibliográfica se plantea la importancia de realizar una investigación tendiente a evaluar el destino de las aflatoxinas a lo largo del proceso de obtención de jarabes de fructosa considerando que fueran elaborados con maíz contaminado con aflatoxinas, en función de la ingestión por un segmento importante de la población que ingiere alimentos endulzados con estos jarabes y que podrían estar ingiriendo aflatoxinas si la materia prima de estas mieles las contuviera.
This contribution's objective is to create consciousness about one of the most important problems... more This contribution's objective is to create consciousness about one of the most important problems at worldwide on the damages provoked by foods contaminated with mycotoxins. Micotoxins are chemical substances produced as secondary metabolites by microscopic fungii that proliferate in foods, especially when stored at high humidity and high temperature conditions.
Introduction: Aflatoxins (AFs) are potent mutagens, carcinogens and teratogens for humans; thus t... more Introduction: Aflatoxins (AFs) are potent mutagens, carcinogens and teratogens for humans; thus their presence in food is of great concern. A maize tortilla survey in Mexico revealed that 17% are contaminated with AFs. The initial process to prepare tortillas includes boiling maize grains with lime and to assumpt that AFs in maize tortillas are destroyed, protecting consumers from their mutagenic effects.
Rice is an important cereal but it is often contaminated with aflatoxins (AFs). The purpose of th... more Rice is an important cereal but it is often contaminated with aflatoxins (AFs). The purpose of this study was to identify and quantify AF (B 1 , B 2 , G 1 , and G 2) in 67 rice samples cultivated in Mexico and Spain, and from imported crops collected in 2008 and 2009. The methodology was validated, the rice samples were concentrated and purified with immunoaffinity columns and were quantified by high-pressure liquid chromatography (HPLC). The average total AF (AFt) in the Spanish rice was 37.3 μg/kg, the range was from 1.6 to 1383 μg/kg, the most contaminated samples being from San Juan de Aznalfarache, Sevilla (AFt = 138.6 μg/kg), from Tortosa, Tarragona (AFt = 104.6 μg/kg), and Calasparra, Murcia (AFt = 103.9 μg/kg). The rice imported from France to Spain had AFt of 26.6 μg/kg and from Pakistan AFt of 18.4 μg/kg, showing less AF contamination than the local one. The rice which originated from Mexico contained (AFt = 16.9 μg/kg), and those imported from the United States (AFt = 14.4 μg/kg) and Uruguay (AFt = 15.6 μg/kg). The imported rice had better quality in terms of the presence of AFs. Practical Application: Rice is both a nutrient and a health risk, because it can be contaminated with aflatoxins that are proven carcinogens. The present study helps humans to know the state of their food and to prevent and avoid aflatoxins.
In Mexico, maize tortillas are consumed on a daily basis, leading to possible aflatoxin exposure.... more In Mexico, maize tortillas are consumed on a daily basis, leading to possible aflatoxin exposure. In a survey of 396 2-kg samples, taken over four sampling days in 2006 and 2007 from tortilla shops and supermarkets in Mexico City, aflatoxin levels were quantified by HPLC. In Mexico, the regulatory limit is 12 mg kg À1 total aflatoxins for maize tortillas. In this survey, 17% of tortillas contained aflatoxins at levels of 3-385 mg kg À1 or values below the limit of quantification (5LOQ) and, of these, 13% were 412 mg kg À1 and 87% were below the regulatory limit. Average aflatoxin concentrations in 56 contaminated samples were: AFB 1 (12.1 mg kg À1 ); AFB 2 (2.7 mg kg À1 ); AFG 1 (64.1 mg kg À1 ) and AFG 2 (3.7 mg kg À1 ), and total AF (20.3 mg kg À1 ).
Aflatoxins (AF) are toxic fungal secondary metabolites and are known mycotoxins pathological to a... more Aflatoxins (AF) are toxic fungal secondary metabolites and are known mycotoxins pathological to animals and humans. Poultry litter is frequently used as a food supplement for ruminants, and when poultry feed contains AF, the litter becomes contaminated as well, thus having an effect on livestock health. This study identified and quantified AF (AFB 1 , AFB 2 , AFG 1 , and AFG 2) from poultry feed and their recovery, together with their metabolites (AFM 1 , AFM 2 , AFP 1 , and aflatoxicol) in litter. An experiment with 25 Hy-Line W-36 hens, in their second production stage, 121 wk old, was carried out. Hens were distributed in 3 groups placed in individual cages and 1 ration of 250 g of feed was given to each hen daily. Nine hens of the control group were fed with clean feed, without AFB 1 ; the other 2 experimental groups, with 8 hens each, were fed with 2 AFB 1 concentrations: 30 and 500 μg·kg −1. The feed was replaced and weighed daily throughout a 7-d period to register the amount of feed consumed by the hens. Litter from each hen was collected, weighed, and dried individually. The chemical analysis of 40 g of each one of the 200 feed and 200 litter samples was chemically extracted and concentrated with immunoaffinity columns for total AF. To quantify AF, calibration curves for each AF were done by HPLC. Feed samples of the 3 groups presented significant difference with AFB 2 and AFG 2 , whereas in litter samples, there were significant differences for AFG 2 in the 500 μg·kg −1 group. Poultry litter had traces of AFM 1 , AFM 2 , AFP 1 , and AFL with no significant differences among treatments. Aflatoxin B 1 prevalence in litter samples can cause damages in livestock because this mycotoxin reduces the digestibil-ity of ruminant feed up to 67%.
Food Additives & Contaminants Part B-surveillance, 2011
In Mexico, maize tortillas are consumed on a daily basis, leading to possible aflatoxin exposure.... more In Mexico, maize tortillas are consumed on a daily basis, leading to possible aflatoxin exposure. In a survey of 396 2-kg samples, taken over four sampling days in 2006 and 2007 from tortilla shops and supermarkets in Mexico City, aflatoxin levels were quantified by HPLC. In Mexico, the regulatory limit is 12 µg kg−1 total aflatoxins for maize tortillas. In this survey, 17% of tortillas contained aflatoxins at levels of 3–385 µg kg−1 or values below the limit of quantification (<LOQ) and, of these, 13% were >12 µg kg−1 and 87% were below the regulatory limit. Average aflatoxin concentrations in 56 contaminated samples were: AFB1 (12.1 µg kg−1); AFB2 (2.7 µg kg−1); AFG1 (64.1 µg kg−1) and AFG2 (3.7 µg kg−1), and total AF (20.3 µg kg−1).
Aflatoxins (AF) are toxic fungal secondary metabolites and are known mycotoxins pathological to a... more Aflatoxins (AF) are toxic fungal secondary metabolites and are known mycotoxins pathological to animals and humans. Poultry litter is frequently used as a food supplement for ruminants, and when poultry feed contains AF, the litter becomes contaminated as well, thus having an effect on livestock health. This study identified and quantified AF (AFB(1), AFB(2), AFG(1), and AFG(2)) from poultry feed and their recovery, together with their metabolites (AFM(1), AFM(2), AFP(1), and aflatoxicol) in litter. An experiment with 25 Hy-Line W-36 hens, in their second production stage, 121 wk old, was carried out. Hens were distributed in 3 groups placed in individual cages and 1 ration of 250 g of feed was given to each hen daily. Nine hens of the control group were fed with clean feed, without AFB(1); the other 2 experimental groups, with 8 hens each, were fed with 2 AFB(1) concentrations: 30 and 500 microg.kg(-1). The feed was replaced and weighed daily throughout a 7-d period to register the amount of feed consumed by the hens. Litter from each hen was collected, weighed, and dried individually. The chemical analysis of 40 g of each one of the 200 feed and 200 litter samples was chemically extracted and concentrated with immunoaffinity columns for total AF. To quantify AF, calibration curves for each AF were done by HPLC. Feed samples of the 3 groups presented significant difference with AFB(2) and AFG(2), whereas in litter samples, there were significant differences for AFG(2) in the 500 microg.kg(-1) group. Poultry litter had traces of AFM(1), AFM(2), AFP(1), and AFL with no significant differences among treatments. Aflatoxin B(1) prevalence in litter samples can cause damages in livestock because this mycotoxin reduces the digestibility of ruminant feed up to 67%.
Rice is an important cereal but it is often contaminated with aflatoxins (AFs). The purpose of th... more Rice is an important cereal but it is often contaminated with aflatoxins (AFs). The purpose of this study was to identify and quantify AF (B1, B2, G1, and G2) in 67 rice samples cultivated in Mexico and Spain, and from imported crops collected in 2008 and 2009. The methodology was validated, the rice samples were concentrated and purified with immunoaffinity columns and were quantified by high‐pressure liquid chromatography (HPLC). The average total AF (AFt) in the Spanish rice was 37.3 μg/kg, the range was from 1.6 to 1383 μg/kg, the most contaminated samples being from San Juan de Aznalfarache, Sevilla (AFt = 138.6 μg/kg), from Tortosa, Tarragona (AFt = 104.6 μg/kg), and Calasparra, Murcia (AFt = 103.9 μg/kg). The rice imported from France to Spain had AFt of 26.6 μg/kg and from Pakistan AFt of 18.4 μg/kg, showing less AF contamination than the local one. The rice which originated from Mexico contained (AFt = 16.9 μg/kg), and those imported from the United States (AFt = 14.4 μg/kg...
The accuracy of the Content should not be relied upon and should be independently verified with p... more The accuracy of the Content should not be relied upon and should be independently verified with primary sources of information. Taylor and Francis shall not be liable for any losses, actions, claims, proceedings, demands, costs, expenses, damages, and other liabilities whatsoever or howsoever caused arising directly or indirectly in connection with, in relation to or arising out of the use of the Content. This article may be used for research, teaching, and private study purposes. Any substantial or systematic reproduction, redistribution, reselling, loan, sub-licensing, systematic supply, or distribution in any form to anyone is expressly forbidden.
International collaborative follow-up investigation of graduating high school students’ understandings of the nature of scientific inquiry: is progress Being made?, 2021
Understandings of the nature of scientific inquiry (NOSI), as opposed to engaging students in inq... more Understandings of the nature of scientific inquiry (NOSI), as opposed to engaging students in inquiry learning experiences, are included in science education reform documents around the world. However, little is known about what students have learned about NOSI during their pre-college school years. The purpose of this large-scale follow-up international project (i.e. 32 countries and regions, spanning six continents and including 3917 students for the high school sample) was to collect data on what exiting high school students have learned about NOSI. Additionally, the study investigated changes in 12th grade students’ NOSI understandings compared to seventh grade (i.e. 20 countries and regions) students’ understandings from a prior investigation [Lederman et al. (2019). An international collaborative investigation of beginning seventh grade students’ understandings of scientific inquiry: Establishing a baseline. Journal of Research in Science Teaching, 56(4), 486–515. https://doi.org/10.1002/tea.21512]. This study documents and discusses graduating high school students’ understandings and compares their understandings to seventh grade students’ understandings of the same aspects of scientific inquiry for each country. It is important to note that collecting data from each of the 130+ countries globally was not feasible. Similarly, it was not possible to collect data from every region of each country. A concerted effort was made, however, to provide a relatively representative picture of each country and the world.
En esta investigación bibliográfica se plantea la importancia de realizar una investigación tendi... more En esta investigación bibliográfica se plantea la importancia de realizar una investigación tendiente a evaluar el destino de las aflatoxinas a lo largo del proceso de obtención de jarabes de fructosa considerando que fueran elaborados con maíz contaminado con aflatoxinas, en función de la ingestión por un segmento importante de la población que ingiere alimentos endulzados con estos jarabes y que podrían estar ingiriendo aflatoxinas si la materia prima de estas mieles las contuviera.
This contribution's objective is to create consciousness about one of the most important problems... more This contribution's objective is to create consciousness about one of the most important problems at worldwide on the damages provoked by foods contaminated with mycotoxins. Micotoxins are chemical substances produced as secondary metabolites by microscopic fungii that proliferate in foods, especially when stored at high humidity and high temperature conditions.
Introduction: Aflatoxins (AFs) are potent mutagens, carcinogens and teratogens for humans; thus t... more Introduction: Aflatoxins (AFs) are potent mutagens, carcinogens and teratogens for humans; thus their presence in food is of great concern. A maize tortilla survey in Mexico revealed that 17% are contaminated with AFs. The initial process to prepare tortillas includes boiling maize grains with lime and to assumpt that AFs in maize tortillas are destroyed, protecting consumers from their mutagenic effects.
Rice is an important cereal but it is often contaminated with aflatoxins (AFs). The purpose of th... more Rice is an important cereal but it is often contaminated with aflatoxins (AFs). The purpose of this study was to identify and quantify AF (B 1 , B 2 , G 1 , and G 2) in 67 rice samples cultivated in Mexico and Spain, and from imported crops collected in 2008 and 2009. The methodology was validated, the rice samples were concentrated and purified with immunoaffinity columns and were quantified by high-pressure liquid chromatography (HPLC). The average total AF (AFt) in the Spanish rice was 37.3 μg/kg, the range was from 1.6 to 1383 μg/kg, the most contaminated samples being from San Juan de Aznalfarache, Sevilla (AFt = 138.6 μg/kg), from Tortosa, Tarragona (AFt = 104.6 μg/kg), and Calasparra, Murcia (AFt = 103.9 μg/kg). The rice imported from France to Spain had AFt of 26.6 μg/kg and from Pakistan AFt of 18.4 μg/kg, showing less AF contamination than the local one. The rice which originated from Mexico contained (AFt = 16.9 μg/kg), and those imported from the United States (AFt = 14.4 μg/kg) and Uruguay (AFt = 15.6 μg/kg). The imported rice had better quality in terms of the presence of AFs. Practical Application: Rice is both a nutrient and a health risk, because it can be contaminated with aflatoxins that are proven carcinogens. The present study helps humans to know the state of their food and to prevent and avoid aflatoxins.
In Mexico, maize tortillas are consumed on a daily basis, leading to possible aflatoxin exposure.... more In Mexico, maize tortillas are consumed on a daily basis, leading to possible aflatoxin exposure. In a survey of 396 2-kg samples, taken over four sampling days in 2006 and 2007 from tortilla shops and supermarkets in Mexico City, aflatoxin levels were quantified by HPLC. In Mexico, the regulatory limit is 12 mg kg À1 total aflatoxins for maize tortillas. In this survey, 17% of tortillas contained aflatoxins at levels of 3-385 mg kg À1 or values below the limit of quantification (5LOQ) and, of these, 13% were 412 mg kg À1 and 87% were below the regulatory limit. Average aflatoxin concentrations in 56 contaminated samples were: AFB 1 (12.1 mg kg À1 ); AFB 2 (2.7 mg kg À1 ); AFG 1 (64.1 mg kg À1 ) and AFG 2 (3.7 mg kg À1 ), and total AF (20.3 mg kg À1 ).
Aflatoxins (AF) are toxic fungal secondary metabolites and are known mycotoxins pathological to a... more Aflatoxins (AF) are toxic fungal secondary metabolites and are known mycotoxins pathological to animals and humans. Poultry litter is frequently used as a food supplement for ruminants, and when poultry feed contains AF, the litter becomes contaminated as well, thus having an effect on livestock health. This study identified and quantified AF (AFB 1 , AFB 2 , AFG 1 , and AFG 2) from poultry feed and their recovery, together with their metabolites (AFM 1 , AFM 2 , AFP 1 , and aflatoxicol) in litter. An experiment with 25 Hy-Line W-36 hens, in their second production stage, 121 wk old, was carried out. Hens were distributed in 3 groups placed in individual cages and 1 ration of 250 g of feed was given to each hen daily. Nine hens of the control group were fed with clean feed, without AFB 1 ; the other 2 experimental groups, with 8 hens each, were fed with 2 AFB 1 concentrations: 30 and 500 μg·kg −1. The feed was replaced and weighed daily throughout a 7-d period to register the amount of feed consumed by the hens. Litter from each hen was collected, weighed, and dried individually. The chemical analysis of 40 g of each one of the 200 feed and 200 litter samples was chemically extracted and concentrated with immunoaffinity columns for total AF. To quantify AF, calibration curves for each AF were done by HPLC. Feed samples of the 3 groups presented significant difference with AFB 2 and AFG 2 , whereas in litter samples, there were significant differences for AFG 2 in the 500 μg·kg −1 group. Poultry litter had traces of AFM 1 , AFM 2 , AFP 1 , and AFL with no significant differences among treatments. Aflatoxin B 1 prevalence in litter samples can cause damages in livestock because this mycotoxin reduces the digestibil-ity of ruminant feed up to 67%.
Food Additives & Contaminants Part B-surveillance, 2011
In Mexico, maize tortillas are consumed on a daily basis, leading to possible aflatoxin exposure.... more In Mexico, maize tortillas are consumed on a daily basis, leading to possible aflatoxin exposure. In a survey of 396 2-kg samples, taken over four sampling days in 2006 and 2007 from tortilla shops and supermarkets in Mexico City, aflatoxin levels were quantified by HPLC. In Mexico, the regulatory limit is 12 µg kg−1 total aflatoxins for maize tortillas. In this survey, 17% of tortillas contained aflatoxins at levels of 3–385 µg kg−1 or values below the limit of quantification (<LOQ) and, of these, 13% were >12 µg kg−1 and 87% were below the regulatory limit. Average aflatoxin concentrations in 56 contaminated samples were: AFB1 (12.1 µg kg−1); AFB2 (2.7 µg kg−1); AFG1 (64.1 µg kg−1) and AFG2 (3.7 µg kg−1), and total AF (20.3 µg kg−1).
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