Determination of aflatoxin M1 in breast milk and related factors

SUMMARY OBJECTIVE: Breastfeeding in women with aflatoxin M1 exposure may be a risk factor for the newborn. Thus, it is crucial to determine aflatoxin M1 levels in breast milk and raise mothers' awareness about nutrition in lactation and other periods. This study was carried out to determine aflatoxin M1 contamination in milk samples taken from mothers who gave birth. METHODS: The study was carried out in the postpartum department of Training and Research Hospital between December 31, 2018, and June 31, 2019, and 90 breastfeeding mothers were included in the study. RESULTS: A total of 75 (83.3%) of the examined samples were found positive. The mean aflatoxin M1 ratio in positive samples was 12.16 pg/mL (5.00-23.18 pg/mL). Mothers' consumption of processed food was associated with aflatoxin M1 levels (p=0.043). It was determined that the aflatoxin M1 levels of mothers who consumed processed food products 1 or 2 times a month were 3.22 times lower than those who consumed 1-2 times a week. CONCLUSIONS: This study emphasized the importance of monitoring aflatoxin M1 levels in breast milk for infant health. It is thought that nutrition education given to mothers during pregnancy will significantly impact aflatoxin M1 results. In addition, the dangers of mycotoxins in mother-infant nutrition should be emphasized regularly in health education.

Aspergillus flavus and Total Aflatoxins Occurrence in Dairy Feed and Aflatoxin M1 in Bovine Milk in Aguascalientes, Mexico.

Contamination of food chains by toxigenic fungi and aflatoxins is a global problem that causes damage to human health, as well as to crop and livestock production. The objective is to evaluate Aspergillus flavus and total aflatoxins (AFs) occurrence in totally mixed rations (TMRs) for dairy cows and aflatoxin M1 (AFM1) in milk for human consumption. Ninety-nine dairy production units located in Aguascalientes, Mexico, were randomly selected, and samples were collected from TMRs, raw milk, and milk marketed in the city in two consecutive agricultural cycles. AFs were quantified in TMRs and milk by indirect enzyme immunoassay and HPLC; aflatoxigenic and molecular (PCR) capacity of monosporic A. flavus isolates in the feed was characterized. All feed, raw, and pasteurized milk samples showed aflatoxin contamination (26.0 ± 0.4 µg/kg, 32.0 ± 1.0, and 31.3 ± 0.7 ng/L, respectively), and a significant proportion (90.4, 11.3, and 10.3%) exceeded the locally applied maximum permissible limits for feed and milk (20.0 µg/kg and 50 ng/L). Aflatoxin contamination in both TMRs and milk indicated a seasonal influence, with a higher concentration in the autumn-winter cycle when conditions of higher humidity prevail. The results obtained suggest the existence of contamination by aflatoxigenic A. flavus and aflatoxins in the diet formulated for feeding dairy cows and, consequently, in the dairy food chain of this region of the Mexican Highland Plateau.

A preliminary study on aflatoxin exposure by urine biomonitoring in Chile.

We assessed the occurrence of aflatoxin M1 (AFM1) in urine in a sample of the MAUCO population-based cohort (n = 120) using an enzyme-linked immune sorbent assay (ELISA) kit specially designed for the analysis of AFM1 in urine. We found AFM1 in the urine of 59% of the participants (> limit of detection), with 12% of the samples being over the limit of quantification. The mean of the quantifiable samples was 0.66 (± 0.35) ng/mg adjusted creatinine, ranging from 0.31 to 1.39 ng/mg creatinine. The mean probable daily intake (PDI) of AFB1 was 0.23 (± 0.37) ng/kg bw according to the upper bound (UB), being significantly higher in women and 0.14 (± 0.23) ng/kg bw in the modified lower bound (mLB) approach, ranging from 0.01 to 1.98 ng/kg bw. The risk of AFB1 was assessed with the margin of exposure (MOE) approach estimated at 2800 in the mean mLB and 1733 in the mean UB. According to the MOE values obtained in this study, aflatoxin B1 exposure must be considered a public health concern and must be taken as a priority for food risk management.

Levels of Aflatoxin M1 in Breast Milk of Lactating Mothers in Monterrey, Mexico: Exposure and Health Risk Assessment of Newborns.

The present study aimed to determine the presence of the aflatoxin M1 (AFM1) in breast milk samples from 123 nursing women and the degree of exposure of infants to this toxin, in the metropolitan area of Monterrey, Nuevo Leon state (northeast Mexico). Upon analysis, 100% of the samples were found to be contaminated with the toxin at an average concentration of 17.04 ng/L, with a range of 5.00 to 66.23 ng/L. A total of 13.01% of the breast milk samples exceeded the regulatory limit of 25 ng/L for AFM1 concentration, set by the European Union. The estimated daily intake for AFM1 and the carcinogenic risk index were also determined in the 0- to 6-, 7- to 12-, 13- to 24-, and 25- to 36-month-old age groups. The AFM1 intake through breast milk ranged from 1.09 to 20.17 ng/kg weight/day, and was higher than the tolerable daily intake, indicating a carcinogenic risk for infants in the age groups of 0- to 24-months old. This evidence demonstrates a susceptibility of breast milk to AFM1 contamination that may suggest a carcinogenic risk for the breastfed infants in Monterrey city, Nuevo Leon state, and the need to control the presence of aflatoxins in foods eaten by nursing mothers.

Quantitative risk assessment for aflatoxin M1 associated with the consumption of milk and traditional dairy products in Argentina.

A quantitative risk assessment for exposure to aflatoxin M1 (AFM1) related to the consumption of milk and traditional dairy products of Argentina was developed. The frequency and concentration of AFM1 was modelled at various stages through the milk processes, considering Argentinean practices. Concentration of AFM1 (0.046 µg/l, 95%CI = 0.002-0.264 µg/l) in raw milk was estimated. The AFM1 concentration in milk was sensitive to the carry-over rate (r = 0.80), and milk yield in the first third of lactation during the spring-summer season (r = 0.11). AFB1 levels in silage (r = 0.22), pasture during the spring-summer season (r = 0.11), concentrate (r = 0.08), and cotton seed (r = 0.05) were the factors most correlated with AFM1 concentrations. Although the results showed that MoE values for the mean and median exposure to AFM1 were < 10,000 in infants, toddlers, and other children, the additional cancer risk due to exposure to AFM1 in infants, toddlers, and other children was 0.007, 0.005, and 0.0009 additional cases per year per 100,000 individuals, respectively, which indicates no health concern. In addition, the percentages of the population exceeding HI values (HI > 1) for exposure to AFM1 for infants, toddlers, and other children were 45%, 49.1%, and 40.6%, respectively. Under this scenario, the most susceptible population at risk was children < 10 years old; therefore, it is necessary to establish measures to prevent contamination of AFM1 in milk and milk products.

Occurrence, exposure evaluation and risk assessment in child population for aflatoxin M1 in dairy products in Brazil.

This study aimed to evaluate the risk concerning child population's health because of the occurrence of AFM1 in UHT milk, powdered milk (PM) and infant formulae (IF). Determination of AFM1 was performed in 60 samples and evaluation of the mycotoxin exposure was carried out through the determination of the estimated daily intake (EDI), whereas risk characterization was evaluated with the calculation of the risk of Hepatocellular Carcinoma (HCC) and the Margin of Exposure (MOE). AFM1 ranged from 150 to 1020 ng/kg, and all the positive samples exceeded the limits stablished by European Community. The EDI for AFM1 ranged according to the age group of the population studied (0-5 years old) from 0.828 to 2.523, 0-2.113 and 0.029-0.833 ng/kg b. w./day in UHT, PM and IF, respectively. The number of HCC cases associated with AFM1 exposure (0.0015 a 0.0045) was higher than the limit of 0.001 case/100,000. MOE values for AFM1 were 728 to 239, considerably below the security margin of 10,000. These results point to a potential risk to the health of Brazilian child population exposed to AFM1 in dairy products.

Efficacy of Potentially Probiotic Fruit-Derived Lactobacillus fermentum, L. paracasei and L. plantarum to Remove Aflatoxin M1 In Vitro.

This study evaluated the efficacy of potentially probiotic fruit-derived Lactobacillus isolates, namely, L. paracasei 108, L. plantarum 49, and L. fermentum 111, to remove aflatoxin M1 (AFM1) from a phosphate buffer solution (PBS; spiked with 0.15 µg/mL AFM1). The efficacy of examined isolates (approximately 109 cfu/mL) as viable and non-viable cells (heat-killed; 100 °C, 1 h) to remove AFM1 was measured after 1 and 24 h at 37 °C. The recovery of AFM1 bound to bacterial cells after washing with PBS was also evaluated. Levels of AFM1 in PBS were measured with high-performance liquid chromatography. Viable and non-viable cells of all examined isolates were capable of removing AFM1 in PBS with removal percentage values in the range of 73.9-80.0% and 72.9-78.7%, respectively. Viable and non-viable cells of all examined Lactobacillus isolates had similar abilities to remove AFM1. Only L. paracasei 108 showed higher values of AFM1 removal after 24 h for both viable and non-viable cells. Percentage values of recovered AFM1 from viable and non-viable cells after washing were in the range of 13.4-60.6% and 10.9-47.9%, respectively. L. plantarum 49 showed the highest AFM1 retention capacity after washing. L. paracasei 108, L. plantarum 49, and L. fermentum 111 could have potential application to reduce AFM1 to safe levels in foods and feeds. The cell viability of examined isolates was not a pre-requisite for their capacity to remove and retain AFM1.

Detección de aflatoxina M1 en muestras de leche cruda de vacas en tanques de enfriamiento en Boyacá (Colombia) / Detection of aflatoxin M1 in raw cow milk samples in cooling tanks in Boyacá (Colombia)

RESUMEN Una de las principales formas de contaminación de la leche con micotoxinas es el consumo de alimentos fermentados que se encuentran contaminados con mohos principalmente de Aspergillus spp., los cuales producen toxinas que pueden llegar a constituirse como un problema para la salud publica debido a su estabilidad térmica y química. El objetivo del presente trabajo fue detectar las concentraciones de aflatoxina M1 en muestras de leche de vacas en tanques de enfriamiento en cuatro municipios del departamento de Boyacá durante un año, determinando las variaciones de acuerdo con la temporada. Se realizó un estudio de corte longitudinal, descriptivo cuantitativo. Se seleccionaron aleatoriamente cuatro tanques de enfriamiento de cuatro municipios distintos del departamento; cada uno se muestreó dos veces al mes durante todo el período de estudio y se procesaron mediante metodología Charm Ez Lite . Se realizó un ANDEVA para determinar las diferencias estadísticas entre las concentraciones de la aflatoxina M1 por cada trimestre. Se determinaron diferencias estadísticas entre cada uno de los trimestres del estudio encontrando un porcentaje de positividad de 74,06% del total de muestras positivas en los trimestres de verano. 28,12% (108) de las muestras tomadas durante todo el estudio fueron positivas, con concentraciones de la toxina que oscilaron entre 0,5 y 2,0 μg/Kg de leche. Se determinó por primera vez en el departamento de Boyacá las concentraciones y variaciones estacionales de aflatoxina M1 en muestras de tanques de enfriamiento de leche, encontrando las mayores concentraciones y número de casos positivos de aflatoxina M1 en los meses de verano.

ABSTRACT One of the main forms of contamination of milk with mycotoxins is the consumption of fermented foods that are contaminated with mold, mainly Aspergillus spp, which produce toxins that can become a public health problem due to their thermal and chemical stability. The objective of the present work was to detect aflatoxin M1 concentrations in cows' milk samples in cooling tanks in four municipalities of the department of Boyacá for one year, determining the variations according to the season. A longitudinal, quantitative descriptive study was carried out, four cooling tanks from four different municipalities in the department were randomly selected, each tank, in each municipality, was sampled twice a month throughout the study period and processed using Charm methodology Ez Lite®, an ANDEVA was performed to determine the statistical differences between aflatoxin M1 concentrations for each quarter. Statistical differences were determined between each of the quarters of the study, finding a positivity percentage of 74.06% of the total positive samples in the summer quarters. 28.12% (108) of the samples taken throughout the study were positive, with toxin concentrations ranging between 0.5 and 2.0 μg/Kg of milk. Seasonal concentrations and variations of aflatoxin M1 in milk cooling tank samples were determined for the first time in the department of Boyacá, finding the highest concentrations and number of positive cases of aflatoxin M1 in the summer months.

Aflatoxin M1 in Nicaraguan and locally made hard white cheeses marketed in El Salvador.

Aflatoxin M1 is a carcinogenic and genotoxic metabolite of Aflatoxins present in food contaminated by fungi for lactating cattle, it is excreted through milk and when used to make cheese, the toxin will also be transferred to the dairy. The contamination of unripened hard white cheese with AFM1 seems to vary according to the season of the year, possibly due to the change of foodstuff, from fresh pasture in the rainy season to dried foods in the dry season and vice versa. This research determined both the prevalence and contents of AFM1 in cheeses of local and Nicaraguan origin marketed in El Salvador, as well as the changes occurred according to the season and the association between levels of AFM1 with meteorological parameters. The significantly higher prevalence of AFM1 contamination in both local cheeses and Nicaraguans, was found in the dry season and the lowest in the rainy season (41 % vs. 20 %; 31 % vs. 0%, respectively), the same trend was observed in AFM1 contents (0.076 vs. 0.036 µg/kg; 0.050 vs. 0.021 µg/kg, respectively). A significant association was demonstrated between levels of AFM1 with the averages of accumulated rainfall and relative humidity according to the sampled season. The prevalence of AFM1 in cheeses indicate that El Salvador and Nicaragua are endemic to dairy contamination by that mycotoxin. Seasonal variation may be due to a lack of rainfall, that promotes the growth of aflatoxigenic fungi in the crops of raw materials, which will be used for feedstuff intended for dairy cattle, thus, the consumption of contaminated food will cause the temporary increase of AFM1 in milk and their derivatives.

Determination of Aflatoxin M1 in Raw Milk from Different Provinces of Ecuador.

Aflatoxin M1 (AFM1) is a mycotoxin from Aspergillus flavus and A. parasiticus, classified as carcinogenic and hepatotoxic. The objective of the present investigation was to determine its presence in raw milk from north-central Ecuador, constituted by the provinces of Pichincha, Manabí, and Santo Domingo de los Tsáchilas. These areas represent approximately 30% of Ecuadorian milk production. By the end of the investigation, a total of 209 raw milk samples were collected, obtained both during the dry (June and August) and rainy seasons (April and November) of 2019. AFM1 concentrations were measured with lateral flow immunochromatographic assays, and 100% of the samples were positive for this mycotoxin, presenting a mean value of 0.0774 µg/kg with a range of 0.023 to 0.751 µg/kg. These AFM1 levels exceeded the European Union regulatory limit of 0.05 µg/kg in 59.3% (124/209) of samples, while only 1.9% (4/209) exceeded the Ecuadorian legal limit of 0.5 µg/kg. By using non-parametric tests, significant differences were determined (p ≤ 0.05) between the provinces for months of study, climatic season (being higher in the dry season), and climatic region (greater in the coast region). On the other hand, there were no significant differences (p ≥ 0.05) between the types of producers or between production systems. Therefore, AFM1 contamination in raw milk does not present a serious public health problem in Ecuador, but a monitoring and surveillance program for this mycotoxin in milk should be developed to prevent consumer health problems.

Spectroscopic studies and molecular modelling of the aflatoxin M1-bovine α-lactalbumin complex formation.

Since the high incidence of aflatoxin M1 (AFM1) in milk and dairy products poses a serious risk to human health, this work aimed to investigate the complex formation between bovine α-lactalbumin (α-La) and AFM1 using different spectroscopic methods coupled with molecular docking studies. Fluorescence spectroscopy measurements demonstrated the AFM1 addition considerably reduced the α-La fluorescence intensity through a static quenching mechanism. The results indicated on the endothermic character of the reaction, and the hydrophobic interaction played a major role in the binding between AFM1 and α-La. The binding site stoichiometric value (n = 1.32) and a binding constant of 2.12 × 103 M-1 were calculated according to the Stern-Volmer equation. The thermodynamic parameters ΔH, ΔS and ΔGb were determined at 93.58 kJ mol-1, 0.378 kJ mol-1 K-1 and -19.17 ±â€¯0.96 kJ mol-1, respectively. In addition, far-UV circular dichroism studies revealed alterations in the α-La secondary structures when the α-La-AFM1 complex was formed. An increased content of the α-helix structures (from 35 to 40%) and the ß-sheets (from 16 to 19%) were observed. Furthermore, protein-ligand docking modelling demonstrated AFM1 could bind to the hydrophobic regions of α-La protein. Overall, the gathered results confirmed the α-La-AFM1 complex formation.

Probiotic bacteria and yeasts adsorb aflatoxin M1 in milk and degrade it to less toxic AFM1-metabolites.

The presence of contaminants such as aflatoxins (AFs) in dairy products constitutes a serious risk to the health of consumers, especially children who are most sensitive to the adverse effects of AFs. The presence of Aflatoxin M1 (AFM1) in milk is a public health problem since dairy products are massively consumed worldwide. The aim of the present work was to select microorganisms capable of reducing AFM1 entry into the food chain through adsorption/degradation strategies. Moreover, the toxicity of AFM1 degradation products was evaluated. All tested strains had the capacity to adsorb 19%-61% AFM1 in milk. These strains also had the ability to degrade AFM1 into metabolites less toxic than the original toxin. Moreover, this is the first study to report harmless and probiotic Pediococcus pentosaceus and Kluveromyces marxianus have the ability to adsorb and degrade AFM1 to less toxic metabolites in milk.

Quantification of aflatoxin M1 carry-over rate from feed to soft cheese.

From January to December 2016, samples of milk and feeds of dairy cattle were monthly collected. The concentration of mycotoxins in all matrices was determined using the enzymatic immunoassay technique. The average concentration of aflatoxin B1 (AFB1), deoxynivalenol (DON) and zearalenone (ZEA) in feed was 3.01, 218.5 and 467 ug/kg, respectively. The average AFB1 carry-over rate was 0.84% with a variation between 0.05 to 5.93%. Particle size of the feed (P = 0.030) and individual milk production (P = 0.001) affected this rate. Mini-soft cheeses were produced using milk naturally contaminated with aflatoxin M1 (AFM1) as raw material to study its distribution both in whey and in cheese. The average level of AFM1 in milk was 0.014 µg/l. None of milk samples exceeded the maximum level accepted for AFB1 by the Southern Common Market (MERCOSUR) legislation (0.5 µg/l) and only 5.5% of samples exceeded the European Union (UE) regulations (0.05 µg/l). After the cheese elaboration, the concentration of AFM1 was determined in whey and in cheese. The greatest proportion (60%) was detected in whey while 40% AFM1 remained in the cheese. However, the concentration of AFM1 was higher in the cheese compared to the original milk.

Frequency and levels of aflatoxin M1 in urine of children in Bogota, Colombia.

A study was conducted to investigate the frequency and levels of AFM1 and AFM2 in urine from children who attended the emergency service of a pediatric referral hospital in Bogota, Colombia. A survey on the consumption of foods likely to be a source of aflatoxins and on sociodemographic variables was conducted as well. The frequency of AFM1 in urine was found to be 41.7% with an average concentration in positive samples of 16 pg mL-1 ± 10.7 pg mL-1 (range > LOD-48.5 pg mL-1). The presence of AFM1 in the urine was related to the consumption of cereals likely to be contaminated with AFB1, especially corn and rice. No detectable levels of AFM2 were found in any sample. The results show that children's exposure to aflatoxins in Colombia is indeed a problem and should be one of the priorities of the health authorities. Continuous monitoring of aflatoxins in foods should be carried out, in compliance with Colombian regulations, using analytical methods that allow determination and quantification of aflatoxins in different biological and non-biological matrices at trace levels.

Occurrence and seasonality of aflatoxin M1 in milk in two different climate zones.

BACKGROUND: Aflatoxin M1 (AFM1) is a mycotoxin found in milk as a result of the ingestion of aflatoxin B1 (AFB1) by dairy cattle. Because of its carcinogenic properties, the control of its occurrence in dairy products is of great importance. We evaluated the occurrence and seasonality of AFM1 in milk from farms with subtropical and temperate climates, where significant milk production occurs. Forty samples of raw milk were collected from bulk tansk milk during the summer (five samples from a subtropical climate and 14 from a temperate climate) and winter (six samples from a subtropical climate and 15 from a temperate climate) months of 2017 and conducted an analysis using an enzyme-linked immunosorbent assay (ELISA) (detection limit 5 ng L-1 ). Data from eight random samples were compared with respect to liquid chromatography with mass spectrometry detection and ELISA. A significant correlation was observed. RESULTS: The presence of AFM1 was detected in 87.50% (n = 35) of the samples analyzed (a mean of 16.66 ng L-1 and a median of 12.42 ng L-1 in positive samples); however, its concentration in all samples was below the maximum limit allowed by European (50 ng L-1 ) and Brazilian (500 ng L-1 ) legislations. There were no significant differences in the levels of AFM1 between the properties located in the two climate zones, in both summer and winter. The estimated daily intake of AFM1 based on the milk analyzed was 0.0107 ng kg-1 day-1 for adolescents, 0.0072 ng kg-1 day-1 for adults and 0.0098 ng kg-1 day-1 for the elderly. CONCLUSION: The present work demonstrated a low exposure to AFM1. © 2018 Society of Chemical Industry.

Determination of Aflatoxin M1 and Ochratoxin A in raw, pasteurizedand UHT milk in Turkey

Background: Mycotoxins produced by yeast and fungi have toxic effects on human and animal health. Aflatoxin B1 (AFB1)is the most toxic hepatocarcinogen to mammals. Aflatoxin M1 (AFM1), which has been found in milk and dairy products,is the hydroxylated metabolite of AFB1. Aflatoxin M1 is formed by the cytochrome P450 enzyme in the liver. OchratoxinA (OTA) is synthesized by Aspergillus and Penicillium species. Ochratoxin A is known to cause teratogenic, immunotoxic,nephrotoxic and carcinogenic effects. Due to the potential harmful effects on human and animal health, OTA has also beenreceiving increased attention globally; however, there is limited information on the presence of OTA in milk and dairy products. The aim of this study was to determine how mycotoxins impact the hygienic quality of raw and heat-processed milk.Materials, Methods & Results: In this study, a total of 105 milk samples were analyzed (35 raw, 35 pasteurized and 35UHT) to identify AFM1 and OTA in raw, pasteurized and ultra-high temperature processing (UHT) milk. The levels ofAFM1 were detected by using the enzyme-linked immunosorbent assay (ELISA). The milk samples were centrifuged inorder to remove the fat content from the milk. After centrifugation, the upper cream layer was withdrawn with a pipette.The non-fat liquid portion was placed in wells at 100 μL for analysis. The concentration of AFM1 in the milk sampleswas analyzed by AFM1 test kit. The milk samples with AFM1 levels greater than 50 ng/L were confirmed by using HighPerformance Liquid Chromatography (HPLC). An Ochratoxin A Serum / Milk ELISA test kit was used for the analysesof OTA. The analyses were made according to the manufacturer’s instructions, and samples were analyzed in duplicate.The absorbance value of milk samples was obtained from the ELISA plate reader at 450 nm...

Determination of Aflatoxin M1 and Ochratoxin A in raw, pasteurizedand UHT milk in Turkey

Background: Mycotoxins produced by yeast and fungi have toxic effects on human and animal health. Aflatoxin B1 (AFB1)is the most toxic hepatocarcinogen to mammals. Aflatoxin M1 (AFM1), which has been found in milk and dairy products,is the hydroxylated metabolite of AFB1. Aflatoxin M1 is formed by the cytochrome P450 enzyme in the liver. OchratoxinA (OTA) is synthesized by Aspergillus and Penicillium species. Ochratoxin A is known to cause teratogenic, immunotoxic,nephrotoxic and carcinogenic effects. Due to the potential harmful effects on human and animal health, OTA has also beenreceiving increased attention globally; however, there is limited information on the presence of OTA in milk and dairy products. The aim of this study was to determine how mycotoxins impact the hygienic quality of raw and heat-processed milk.Materials, Methods & Results: In this study, a total of 105 milk samples were analyzed (35 raw, 35 pasteurized and 35UHT) to identify AFM1 and OTA in raw, pasteurized and ultra-high temperature processing (UHT) milk. The levels ofAFM1 were detected by using the enzyme-linked immunosorbent assay (ELISA). The milk samples were centrifuged inorder to remove the fat content from the milk. After centrifugation, the upper cream layer was withdrawn with a pipette.The non-fat liquid portion was placed in wells at 100 μL for analysis. The concentration of AFM1 in the milk sampleswas analyzed by AFM1 test kit. The milk samples with AFM1 levels greater than 50 ng/L were confirmed by using HighPerformance Liquid Chromatography (HPLC). An Ochratoxin A Serum / Milk ELISA test kit was used for the analysesof OTA. The analyses were made according to the manufacturers instructions, and samples were analyzed in duplicate.The absorbance value of milk samples was obtained from the ELISA plate reader at 450 nm...(AU)

Effect of thermoultrasound on aflatoxin M1 levels, physicochemical and microbiological properties of milk during storage.

The aim of this research was to determine the physicochemical properties, microbial counts and aflatoxin M1 (AFM1) levels of thermoultrasonicated, pasteurized and untreated milk (control) at days 1, 7 and 14 of storage. Thermoultrasound treatment was performed at a rate of 20 kHz for 10 or 15 min and 95% amplitude on homogenized and non-homogenized milk samples. Results showed that most physicochemical parameters were within the Mexican norms established for milk. Ultrasound treatment for 15 min reduced solids precipitation (p < 0.05) in unhomogenized milk during storage as compared to the pasteurized milk. All samples complied with aerobic mesophilic counts limits set by the Mexican norm except the control and the homogenized milk sample which was thermoultrasonicated for 10 min. Enterobacteriaceae counts of pasteurized and 15 min-thermoultrasound homogenized milks complied with the norm. The lowest levels of AFM1 were found in the 10 min-thermoultrasound unhomogenized milk (0.15 ±â€¯0.05 pg AFM⁠1E/mL) one day after storage. Thermoultrasound did not affect the color of samples but homogenized milk treated for 10 min exhibited less total color difference. A high phenolic content was found in thermoultrasound and pasteurized milks on day 1. Thermoultrasound could be an alternative to milk pasteurization that preserves the physicochemical and microbiological quality of milk while reducing AFM1 levels.

Occurrence of Aflatoxin M1 in cow milk in El Salvador: Results from a two-year survey.

Aflatoxin M1 (AFM1) is a metabolite of Aflatoxin B1 (AFB1) and is excreted through cow´s milk. AFM1 contamination of milk is extended geographically and there might be seasons-related variations for both prevalence and contents, with higher than average values in regions with long periods of drought like El Salvador. Therefore, this project quantified AFM1 levels in raw cow milk and AFs in cattle feedstuffs, during the transitional dry-rainy seasons of two consecutive years and it determined the variation of occurrence and contents associated to drought. Significant variations were shown from year to year in the prevalence of contamination (30% vs. 20%) and in the average levels of AFM1 in milk (0.056 vs 0.039 µg/kg), associated with drought and increased temperature. The AFs median levels raised significantly with the drought period (from 22.5 to 10.3 µg/kg). A significant relationship was demonstrated between AFs levels and those of AFM1, both in the year with drought and without that condition. AFM1 positive cases and its levels in milk increase in drought and hot conditions, AFs levels in the cattle feed tend to be higher with the same, as well. Both relationship between AFs and AFM1 levels and their association with drought were demonstrated. So that, heat and drought stress conditions can evoke raising effects on both Aflatoxins level and occurrence due to AFM1 in milk is a carryover from AFs contaminated feedstuffs ingested by dairy cows.

Assessment of Aflatoxin M1 and M2 exposure risk through Oaxaca cheese consumption in southeastern Mexico.

The present study evaluated the exposure of Southeast Mexican population to Aflatoxin M1 (AFM1) and M2 (AFM2) through the consumption of Oaxaca cheese. The intake of Oaxaca cheese was assessed via a food 7-day dairy questionnaire (N = 1100, 2014 and 2015). Thirty Oaxaca cheeses were randomly sampled, and the origin of the samples was also investigated. AFM1 and AFM2 were quantified by HPLC-FD. The exposure was assessed through the combination of the Probabilistic Density Functions (probabilistic approach). The percentage of the population at risk was calculated through the population exceeding the toxicological reference values (TDI). The risk assessment revealed that the population at higher risk to AFM1 and AFM2 was the children, followed by the adolescents and adult women. To our knowledge, the present study is the first to assess the exposure risk of different age groups of a population to AFM1 and AFM2 through the consumption of cheese.