A study was conducted to screen the occurrence and level of aflatoxin M1 (AFM1) in urine samples of 206 urban and rural residents in Terengganu, Malaysia. The level of AFM1 was quantified by competitive enzyme-linked immune-absorbent assay (ELISA). Of the 206 samples, 84 were positive for AFM1 (40.8%) in a range of 0.07-5.53 ng/ml (mean = 0.589 ng/ml). Residents of Terengganu are moderately exposed to AFM1. Age, ethnicity, marital status and employment status were associated with urinary level of AFM1. Subjects aged 30 years and above, non-Malays, married, and those unemployed had significantly higher levels of urinary AFM1 (p
Probiotic Lactobacillus casei Shirota (LcS) is a potential decontaminating agent of aflatoxin B1 (AFB1). However, few studies have investigated the influence of diet, especially a high protein (HP) diet, on the binding of AFB1 by probiotics. This research was conducted to determine the effect of HP diet on the ability of LcS to bind AFB1 and reduce aflatoxin M1 (AFM1) in AFB1-induced rats. Sprague Dawley rats were randomly divided into three groups: A (HP only), B (HP + 108 CFU LcS + 25 μg AFB1/kg BW), and C (HP + 25 μg AFB1/kg BW). Levels of AST and ALP were higher in all groups but other liver function's biomarkers were in the normal range, and the liver's histology showed no structural changes. The urea level of rats in group B (10.02 ± 0.73 mmol/l) was significantly lower (p < 0.05) than that of rats in group A (10.82 ± 0.26 mmol/l). The presence of carcinoma in the small intestine and colon was more obvious in group C than in group B. Moreover, rats in group B had significantly (p < 0.05) lower AFM1 concentration (0.39 ± 0.01 ng/ml) than rats in group C (5.22 ± 0.28 ng/ml). Through these findings, LcS supplementation with HP diet alleviated the adverse effects of AFB1 by preventing AFB1 absorption in the small intestine and reducing urinary AFM1.
Aflatoxin is a food contaminant and its exposure through the diet is frequent and ubiquitous. A long-term dietary aflatoxin exposure has been linked to the development of liver cancer in populations with high prevalence of aflatoxin contamination in foods. Therefore, this study was conducted to identify the association between urinary aflatoxin M₁ (AFM₁), a biomarker of aflatoxin exposure, with the dietary intake among adults in Hulu Langat district, Selangor, Malaysia. Certain food products have higher potential for aflatoxin contamination and these were listed in a Food Frequency Questionnaire, which was given to all study participants. This allowed us to record consumption rates for each food product listed. Concomitantly, urine samples were collected, from adults in selected areas in Hulu Langat district, for the measurement of AFM₁ levels using an ELISA kit. Of the 444 urine samples collected and tested, 199 were positive for AFM₁, with 37 of them exceeding the limit of detection (LOD) of 0.64 ng/mL. Cereal products showed the highest consumption level among all food groups, with an average intake of 512.54 g per day. Chi-square analysis showed that consumption of eggs (X² = 4.77, p = 0.03) and dairy products (X² = 19.36, p < 0.01) had significant associations with urinary AFM₁ but both food groups were having a phi and Cramer's V value that less than 0.3, which indicated that the association between these food groups' consumption and AFM₁ level in urine was weak.
The determination of aflatoxin M1 in milk using high performance liquid chromatography with photochemical post-column derivatization and fluorescence detection is described. The samples were first extracted and clean-up using the immunoaffinity AFLATEST column originally targeted for aflatoxins B1, B2, G1 and G2. The separation of aflatoxin M1 were performed using C18 Hypersil gold (150mm×4.6mm, 5μm) column at 40°C under isocratic elution. Fluorescence detector (FLD) was set at 360nm and 440nm as excitation and emission, respectively. The use of methanol to replace acetonitrile as the mobile phase resulted in ∼67% peak area enhancement of AFM1. The limit of detection (LOD) and quantification (LOQ) of the analytical method after post-column derivatization without evaporation/reconstitution with mobile phase was 0.0085μgL(-1) and 0.025μgL(-1) respectively. However, LOD and LOQ improved to 0.002 and 0.004μgL(-1) respectively with the addition of evaporation/reconstitution step. The method was statistically validated, showing linear response (R(2)>0.999), good recoveries (85.2-107.0%) and relative standard deviations (RSD) were found to be ≤7%. The proposed method was applied to determine AFM1 contamination in various types of milk and milk products. Only 2 samples were contaminated with aflatoxin M1 (10% incidence). However, the contamination level is below the Malaysian and European legislation limits.
This study aimed to find the association between urinary aflatoxin M(1) level and milk and dairy products consumption. Of 160 morning urine samples collected, aflatoxin M(1) was detected in 61.3 % samples (n = 98) [mean ± SD = 0.0234 ± 0.0177 ng/mL; range = 0-0.0747 ng/mL]. Of these positive samples, 67.3 % (n = 66) had levels above the limit of detection. Respondents with intake of milk and dairy products above median (67.79 g/day) had significantly high level of AFM(1) compared to those with low intake. A significant and positive association (φ = 0.286) was found between milk and dairy products consumption and urinary aflatoxin M(1) level.
Human exposure to aflatoxin is through the diet, and probiotics are able to bind aflatoxin and prevent its absorption in the small intestine. This study aimed to determine the effectiveness of a fermented milk drink containing Lactobacillus casei Shirota (LcS) (probiotic drink) to prevent aflatoxin absorption and reduce serum aflatoxin B1-lysine adduct (AFB1-lys) and urinary aflatoxin M1 concentrations. The present study was a randomised, double-blind, cross-over, placebo-controlled study with two 4-week intervention phases. In all, seventy-one subjects recruited from the screening stage were divided into two groups--the Yellow group and the Blue group. In the 1st phase, one group received probiotic drinks twice a day and the other group received placebo drinks. Blood and urine samples were collected at baseline, 2nd and 4th week of the intervention. After a 2-week wash-out period, the treatments were switched between the groups, and blood and urine samples were collected at the 6th, 8th and 10th week (2nd phase) of the intervention. No significant differences in aflatoxin biomarker concentrations were observed during the intervention. A within-group analysis was further carried out. Aflatoxin biomarker concentrations were not significantly different in the Yellow group. Nevertheless, ANOVA for repeated measurements indicated that AFB1-lys concentrations were significantly different (P=0·035) with the probiotic intervention in the Blue group. The 2nd week AFB1-lys concentrations (5·14 (SD 2·15) pg/mg albumin (ALB)) were significantly reduced (P=0·048) compared with the baseline (6·24 (SD 3·42) pg/mg ALB). Besides, the 4th week AFB1-lys concentrations were significantly lower (P<0·05) with probiotic supplementation than with the placebo. Based on these findings, a longer intervention study is warranted to investigate the effects of continuous LcS consumption to prevent dietary aflatoxin exposure.