Aflatoxin M1 contamination in dairy products marketed in Iran during winter and summer

In the present study, 298 dairy product samples consisting of pasteurized milk (91 samples), yoghurt (68 samples), white cheese (72 samples), butter (31 samples) and ice cream (36 samples) collected from popular markets in four large Iranian cities were examined for aflatoxin M₁ (AFM₁) by thin layer chromatography (TLC) technique. The toxin was detected in 66 (72.5%) pasteurized milk samples (mean: 0.052 μg/l; range: 0.013–0.250 μg/l), 45 (66.1%) yoghurt samples (mean: 0.032 μg/kg; range: 0.015–0.119 μg/kg), 59 (81.9%) white cheese samples (mean: 0.297 μg/kg; range: 0.030–1.200 μg/kg), 8 (25.8%) butter samples (mean: 0.005 μg/kg; range: 0.013–0.026 μg/kg) and 25 (69.4%) ice cream samples (mean: 0.041 μg/kg; range: 0.015–0.132 μg/kg). The concentration of AFM₁ in 36.2%, 20.6%, 30.5%, 9.6% and 27.7% of pasteurized milk, yoghurt, white cheese, butter and ice cream samples, respectively, were higher than Iranian national standard limits. Levels of AFM₁ in samples of pasteurized milk, yoghurt, butter and ice cream collected in winter were significantly higher (P < 0.05) than those collected in summer. In the case of white cheese, level of AFM₁ was higher in winter than in summer, but the difference was not statistically significant (P > 0.05). The results indicated that the contamination of the dairy products in such a level could be a serious public health problem at the moment.     

Aflatoxin M1 and ochratoxin A in human milk in Ribeirão Preto-SP,Brazil

The objective of this study was to determine the extent of aflatoxin M₁ (AFM₁) and ochratoxin A (OTA) contamination in human breast milk in the city of Ribeirão Preto, São Paulo State, Brazil. During 2012, 100 samples of human milk were collected at the local Human Milk Bank. The method comprised, immunoaffinity column purification and isolation, liquid chromatography separation and fluorescence detection. The average percentage recoveries of AFM₁ and OTA spiked at 20 and 50 ng/L in control human milk were 78.1 ± 11.7% and 73.7 ± 9.6%, respectively. The average relative standard deviations of AFM₁ and OTA spiked at the same levels were 11.7 and 9.6% respectively. The limits of detection was 0.3 ng/L for AFM₁ and OTA. The limit of determination was 0.8 ng/L for both mycotoxins. This method was used to analyze 100 human milk samples, of which, two samples were found to contain AFM₁ at level greater than 0.3 ng/L. OTA was detected in 66 samples (66%), wherein 32 were above the limit of detection and 34 were in the range of from 0.8 to 21 ng/L. Results of our study indicate that breast-fed Brazilian infants had only an insignificant exposure to AFM₁ and OTA.     

Occurrence of aflatoxin M1 in pasteurised,UHT milk and milk powder from goat origin

In the present study, 36 samples of pasteurised, ultra-high-temperature (UHT) treated and goat milk powder traded in the city of Campinas, Brazil, were analysed for aflatoxin M₁ (AFM₁), from October to December 2004 and March to May 2005. Results showed 25 (69.4%) positive samples for AFM₁ at levels of 0.011–0.161 μg L⁻¹ of milk, which were below the tolerance limit of 0.500 μg L⁻¹ as adopted for AFM₁ in milk by Brazilian regulations. Mean levels of AFM₁ in pasteurised, UHT and goat milk powder were 0.072 ± 0.048, 0.058 ± 0.044 and 0.056 ± 0.031 μg L⁻¹, respectively. It is concluded that the incidence of AFM₁ in goat milk traded in Campinas is high, but at levels that probably leads to a non-significant human exposure to AFM₁ by consumption of goat milks.     

Presence of aflatoxin M1 in milk and infant milk products in Tehran,Iran

Aflatoxins are highly toxic, mutagenic, teratogenic and carcinogenic compounds. The purpose of this survey was to determine natural occurrence and level of AFM₁ in pasteurized liquid milk, infant formula and milk-based cereal weaning food consumed in Tehran, Iran.A total of 328 branded milk products and liquid milk samples were collected and investigated by Enzyme Linked Immuno Sorbent Assay (ELISA).The samples of pasteurized liquid milk (n = 128), infant formula (n = 120) and milk-based cereal weaning food (n = 80) showed that the incidence of contamination with AFM₁ is 96.3%, the presence of AFM₁ in each group was 72.2 ± 23.5, 7.3 ± 3.9 and 16.8 ± 12.5 ng/kg, ranging between 31–113, 1–14 and 3–35 ng/kg, respectively.In general, the amount of AFM₁ in 100 (78%) of liquid milk samples and 24 (33%) of milk-based weaning food was higher than the maximum tolerance limit accepted by European Union, but in all of the infant formula samples was lower (European Communities and Codex Alimentarius has prescribed a limit of 50 ng/kg for AFM₁ in milk and 25 ng/kg in infant milk products).     

A study on the occurrence of aflatoxin M1 in Iranian Feta cheese

This study was undertaken to determine the presence and levels of aflatoxin M₁ (AFM₁) in cheeses produced by different plants in the province of Tehran. For this purpose, a total of 80 cheese samples analyzed, and thin layer chromatography (TLC) was used to determine the presence and levels of AFM₁.AFM₁ was found in 82.5% of 80 of the cheese samples examined. The range of contamination levels varied among different months. AFM₁ in May, August, November, February samples ranged from 0.17 to 1.30, 0.15 to 2.41, 0.16 to 1.11, and 0.19 to 2.05 μg/kg, respectively, while the mean values were 0.41, 0.35, 0.36, and 0.52 μg/kg, respectively.The highest mean concentration of aflatoxin M₁ (AFM₁) was registered in February samples (0.52 μg/kg). The lowest mean concentration of aflatoxin M₁ was registered in August samples (0.35 μg/kg).Statistical evaluation showed that there were not significant differences (P > 0.05) between the concentrations of AFM₁ of cheese samples taken in May and August with November and February. In other words, AFM₁ contents of cheese samples taken in November and August were not lower than cheese samples taken in May and February. Almost 60.6% of the contaminated samples exceeded the maximum acceptable levels (0.25 μg/kg) that accepted by some of the countries such as Turkey.It was therefore concluded that, high occurrence of AFM₁ in cheese samples were considered to be possible hazards for human health.     

Aflatoxin M1 in raw milk in Croatia

In this study the levels of aflatoxin M₁ (AFM₁) of 61 milk samples delivered from small milking farms were determined in January, February, March and April (winter–spring season), and June, July and September (summer–autumn season) of 2009. The AFM₁ concentration was determined by competitive enzyme-immunoassay method. The maximum mean concentrations of AFM₁ recorded in winter–spring season were in the range of 35.8–58.6 ng/l and in summer–autumn season in the range of 11.6–14.9 ng/l. The AFM₁ levels determined in January, February, March and April were significantly higher in accordance with concentration of AFM₁ in June, July and September (P < 0.05 to P < 0.0001, respectively). Also, there was significant difference (P < 0.0001) between the mean concentrations of AFM₁ in samples taken all together in winter–spring and summer–autumn season. Only in one sample delivered in February the level of AFM₁ was higher than the maximum tolerance limit (50 ng/l). Therefore, it was concluded that in 98.4% of milk samples in Croatia the levels of AFM₁ were below maximum tolerance level accepted by the European Union.     

Estimate of aflatoxin M1 exposure in milk and occurrence in Brazil

The presence of aflatoxin M₁ (AFM₁) was investigated in 125 samples of powdered milk, pasteurized milk and ultra high treated (UHT) milk in the city of São Paulo, and estimates of AFM₁ intake were assessed. The samples were analysed using an immunoaffinity column for cleanup and a HPLC-FLD for determining AFM₁. The quantification limit was 10 ng/kg. AFM₁ was found in 119 (95.2%) at levels ranging from 10 to 200 ng/kg with mean concentration of 31 ng/kg. The average daily intake estimated for AFM₁ was 1 ng/kg bw per day for children and 0.188 ng/kg bw per day for adults.     

Occurrence of AFM1 in urine samples of a Brazilian population and association with food consumption

This survey evaluated the presence of AFM₁ in human urine samples from a specific Brazilian population, as well as corn, peanut, and milk consumption measured by two types of food inquiry. Urine samples from donors who live in the city of Piracicaba, State of São Paulo, Brazil were analyzed to detect the presence of aflatoxin M₁ (AFM₁), an aflatoxin B₁ metabolite, which may be used as aflatoxin B₁ exposure biomarker. The AFM₁ analysis was performed using immunoaffinity clean-up and detection by high-performance-liquid chromatography with fluorescence detector. A total of 69 samples were analyzed and 45 of them (65%) presented contaminations ⩾1.8 pg ml⁻¹, which was the limit of quantification (LOQ). Seventy eight percent (n = 54) of the samples presented detectable concentrations of AFM₁ (>0.6 pg ml⁻¹). The AFM₁ concentration among samples above LOQ ranged from 1.8 to 39.9 pg ml⁻¹. There were differences in food consumption profile among donors, although no association was found between food consumption and AFM₁ concentration in urine. The high frequency of positive samples suggests exposure of the populations studied to aflatoxins.     

Aflatoxin M1 levels of Turkish white brined cheese

This study was undertaken to determine the presence and levels of aflatoxin M₁ (AFM₁) in Turkish white brined cheese consumed in the province of Erzurum, Turkey. For this purpose, a total of 193 cheese samples were randomly obtained from retail outlets and Enzyme Linked Immunosorbent Assay (ELISA) technique was used to determine the presence and levels of AFM₁. AFM₁ at detectable level (50 ng/kg) was found in 82.4% of the samples. The concentration of AFM₁ in samples ranged from 52 to 860 ng/kg. Of the samples, 26.4% exceed the legal limit of 250 ng/kg established by Turkish Food Codex. It was concluded that widespread occurrence of AFM₁ in Turkish white brined cheese samples were considered to be possible hazards for public health especially children.     

Changes in the concentration of aflatoxin M1 during manufacture and storage of White Pickled cheese

In this study White Pickled cheese was produced from cow’s milk contaminated artificially with aflatoxin M₁ (AFM1) at two different levels, 1.5 and 3.5 μg/kg (ppb), and the effects of process stages on the AFM1 contents were investigated. Pasteurization at 72 °C for 2 min caused losses of AFM1 about 12% and 9%, respectively, in milk contaminated with 1.5 μg/kg AFM1, and 3.5 μg/l AFM1. These losses were found to be statistically significant (P < 0.01). After the cheese production, about 56% and 59% of total AFM1 remained in cheese–curd while about 32% of total AFM1 transferred to the whey for both 1.5 μg/kg and 3.5 μg/kg AFM1 contaminated milk. After 3-month storage in brine, AFM1 content of cheeses produced from 1.5 and 3.5 μg/kg AFM1 contaminated milks decreased by 2.9% and 2.8%, respectively. Changes in AFM1 content of cheese samples were found statistically insignificant (P > 0.05 and P > 0.01) for 3-month storage periods.     

Seasonal variation of aflatoxin M1 in raw milk from the Yangtze River Delta region of China

The objective of this study was to evaluate the occurrence of aflatoxin M₁ (AFM₁) in raw milk samples from 18 dairy farms in the Yangtze River Delta region during four different seasons. A total of 72 tank milk samples was collected with 18 samples for each season. Milk AFM₁ was detected using LC-MS/MS. The AFM₁ was detected in 43 milk samples (59.7%) ranging in concentration from 10 to 420 ng/L. The concentration of AFM₁ in raw milk was significantly higher during the winter (123 ng/L) than during other seasons (P < 0.05). There was no significant difference between the spring (29.1 ng/L), summer (31.9 ng/L), and autumn (31.6 ng/L) (P > 0.05) seasons. This indicates that raw milk collected during the winter is at high risk for AFM₁ and that seasonal factors should be considered for the management of aflatoxins in both the feed and milk.     

Aflatoxin M1 in raw,pasteurized and powdered milk available in the Syrian market

The incidence of contamination of aflatoxin M1 (AFM1) in milk samples collected from the Syrian market was investigated by using the competitive enzyme linked immunosorbent assay (ELISA) technique. A total of 126 samples composed of raw cow milk (74 samples), raw sheep milk (23), raw goat milk (11), pasteurized cow milk (10) and powdered milk (8) showed that 80% of tested samples were contaminated with various levels of AFM1 ranging from >20 to 765 ng/l. Percentages of AFM1-contaminated samples exceeding the American, Syrian and European tolerance limits were 22%, 38% and 52%, respectively.The range of contamination was relatively higher in pasteurized milk than in raw cow and sheep milk. 80% of AFM1-contaminated pasteurized cow milk samples exceeded the European tolerance limit with a range of contamination between 89 and 765 ng/l. Percentages of contaminated raw cow, sheep and goat milk exceeding the European tolerance limit were 59%, 24% and 14%, respectively.Milk powder was almost free of AFM1 contamination with only one sample containing a concentration lower than the European tolerance limit (12 ng/l).Extrapolation of aflatoxin B1 (AFB1) from AFM1 levels of contamination in milk samples indicates that contamination in dairy cattle feeds may range from 0.5 to 47.8 μg/kg.     

The seasonal variation of aflatoxin M1 in milk and dairy products and assessment of dietary intake in Punjab,Pakistan

Total 372 samples (169 sample from summer and 203 samples from winter) of milk and dairy products were collected from major cities of Punjab, Pakistan, during 2014–2015. The aflatoxin M₁ (AFM₁) levels were analyzed using HPLC, equipped with floresceⁿce detector. The results have showed that AFM₁ was detected in 77 (45.5%) samples of milk and dairy products from summer at the range of LOD to 229.6 ng/L, and 114 (56.1%) samples from winter at a range of LOD to 345.8 ng/L. The highest mean of AFM₁ i.e. 94.9 ± 5.4 ng/L from summer and 129.6 ± 8.4 ng/L from winter was detected in raw milk samples. The results have shown that 37.5% of milk, 32% of UHT milk, 12.5% of powdered milk, 20% of flavored milk, 20% of yogurt and 16% of flavored milk samples from summer were found exceeded the recommended levels of AFM₁ i.e 50 ng/L (European Union permissible limit), as compared to 38.1%, 37.1%, 15.6%, 21.4%, 27.7% and 40% samples of milk, UHT milk, powdered milk, flavored milk, yogurt and flavored yogurt from winter, respectively. The mean level of AFM₁ in samples of milk, UHT milk and powdered milk samples from winter season has significantly (p˂ 0.05) higher as compared to the mean levels in samples from summer season. The dietary exposures of AFM₁ in milk and dairy products were calculated in five different age groups and the highest level of 3.42 and 3.33 ng/L/day in summer and 4.7 and 4.6 ng/L/day in winter were found in 1–5 years of male and female infants, respectively. The results of present study have shown significant levels of AFM₁ in milk and dairy products from Punjab, Pakistan and could pose considerable thereat to the health of local population.     

A sensitive and validated method for determination of melamine residue in liquid milk by reversed phase high-performance liquid chromatography with solid-phase extraction

A sensitive and validated method for the determination of melamine residue in liquid milk is developed using reversed phase high-performance liquid chromatography-diode array detection (RP-HPLC-DAD) with solid-phase extraction (SPE). The conditions of the extraction, SPE and HPLC were investigated and optimized. The linearity is satisfactory in the range of 0.1–50 μg/mL with a correlation coefficient of 0.9998. Under the optimal conditions, the method limit of detection (LOD) and method limit of quantification (LOQ) were 18 μg/kg and 60 μg/kg, respectively. The recovery of melamine for milk samples spiked with 0.10–3 mg/kg was in the range of 85.5–99.3% with the RSDs (n = 3) of 2.3–3.7%. The intra-day assay precision (RSD) was 5.6% for five replicates of quality control milk sample at 2 mg/kg level. Confirmation of the identities of melamine was achieved by monitoring the two transitions in multiple-reaction monitoring (MRM) mode, and has been applied successfully for the determination of melamine residue in liquid milk samples. The confirmatory method can permit the detection of melamine residues at levels as low as 60 μg/kg in different liquid milks.     

Determination of Aflatoxin B1 levels in powdered red pepper

Insufficient hygiene conditions during drying, transport and storage stages in the production of red pepper could cause microbiological and mycological growth which could result in the formation of mycotoxins. This study was designed to assess the aflatoxin B₁ levels in 100 samples of powdered red pepper randomly obtained from markets in Istanbul using microtitre plate Enzyme Linked Immunosorbent Assay (ELISA). Aflatoxin B₁ levels were below the minimum detection limit (0.025 μg/kg) in 32 samples, between 0.025 and 5 μg/kg in 50 samples, whilst 18 samples had unacceptable contamination levels higher than the maximum tolerable limit (5 μg/kg), according to the Turkish Food Codex and the European Commission.     

Prevalence,genetic diversity and antimicrobial susceptibility of Listeria monocytogenes isolated from open-air food markets in Greece

A total of 210 food samples originating from milk products, ready-to-eat salads, raw meat and raw meat products purchased in ten open-air market places in Thessaloniki, Greece, were analyzed for the presence of Listeria monocytogenes. Thirty (14.3%) contained L. monocytogenes with the highest prevalence in raw meat (27.5%), raw meat products (18%) and cheese (8%). The strains were susceptible to 16 antimicrobials as determined by microbroth dilution, except one strain which displayed resistance to tetracycline (MIC > 32 μg/ml). This strain carried the tetracycline resistance gene tet(M). Pulsed-field gel electrophoresis (PFGE) revealed a low genetic diversity among the isolates, irrespective of their origin. This suggests that dominant L. monocytogenes clones are widespread in different food product types in open-air food markets in Greece. The high prevalence of L. monocytogenes in these products indicates that appropriate hygienic measures and periodic bacteriological controls are also necessary in open-air food markets to reduce contamination with food-borne pathogens. Greek specialties made with raw meat and raw milk may contain L. monocytogenes and should not be consumed by persons at risk.     

A Turkey survey of hygiene indicator bacteria and Yersinia enterocolitica in raw milk and cheese samples

In this research, a total of 200 dairy (raw milk, cheese) samples obtained from Ankara, were examined for the presence of Yersinia spp., total coliform and Escherichia coli. As expected, raw milk 55% (55/100) were significantly contaminated with Yersinia spp., than cheese samples 14% (14/100). Y. enterocolitica was the most commonly isolated species, and was recovered from 47.3% in raw milk 35.7% in cheese samples. The other Yersinia spp. were identified as Y. frederiksenii (31.0%, 21.4%), Y. kristensenii (12.7%), Y. intermedia (7.2%, 7.1%) and atypical Yersinia spp. (1.8%, 35.7%) in raw milk and cheese samples, respectively. All the samples of cheese examined were negative for Y. kristensenii. All Y. enterocolitica strains tested gave negative results in the autoagglutination tests and crystal violet binding test.Furthermore total coliform bacteria and E. coli were investigated in these samples. According to the analysis results, most of the samples containing Yersinia spp.were found high number of viable count cell total coliform than E. coli. Total coliform bacteria and E. coli, were detected (3.0 × 10⁴ cfu/ml and 1.5 × 10⁴ cfu/ml) in four milk samples containing Y. enterocolitica while, they were detected (2.5 × 10⁴ cfu/ml and 1.0 × 10⁴ cfu/ml) in eight milk samples containing Y. enterocolitica. In the present study, total coliform bacteria and E. coli were detected >1.1 × 10⁵ cfu/g in six cheese samples containing Y. enterocolitica and atypical Yersinia spp. The results indicate that Yersinia spp. is more likely to be isolated from foods with a high level of coliforms than from foods with low coliform counts.     

Validation of the procedure for the determination of aflatoxin B1 in animal liver using immunoaffinity columns and liquid chromatography with postcolumn derivatisation and fluorescence detection

The validation of the procedure for the determination of aflatoxin B₁ in animal liver (pig, chicken, turkey, beef, calf) was performed. The limit of detection (LOD) and limit of quantification (LOQ) were 2 ng/kg and 7.8 ng/kg, respectively. The repeatability of measurements, represented by the standard deviation (RSD_r) was 7.5%, 7.1%, and 4.8% at the contamination levels of 0.025 μg/kg, 0.050 μg/kg, and 0.075 μg/kg, respectively. The relative standard deviation for the within-laboratory reproducibility (RSD_R) was 18% at the level of 0.025 μg/kg and 22% at the levels of 0.050 μg/kg and 0.075 μg/kg. The measurement uncertainties at the same contamination levels were ±0.007 μg/kg, ±0.016 μg/kg, and ±0.023 μg/kg, respectively. The mean recovery was 72.8%, the decision limit (CCα) 0.063 μg/kg and the detection capability (CCβ) 0.080 μg/kg. The results indicate that the procedure is suitable for the determination of aflatoxin B₁ in animal liver and can be implemented for the routine analysis.     

Investigation of iodine in infant starting,special and follow-on formulae

Newborn babies are entirely dependent on mother’s milk and in special cases on infant starting, follow-on and special formulae as their only iodine source. In the present work, we investigated the iodine content of different infant formulae and examined the improvements made in the last decade. Radiochemical neutron activation analysis was employed to determine the content of iodine in the selected samples. We compared the values obtained with the declared values and all investigated infant formulae, with the exception of three, showed insufficient agreement with the declared values. In the case of special formulae, only one of five investigated products was in good agreement with the declared value. The values of iodine obtained for eighteen different infant formulae ranged from 0.18 to 1.82 μg/g, which converted to daily intake by considering the accepted consumption of milk for infants ranged from 20 to 220 μg/day. Calculated from our results, the range of iodine contents for starting formulae, prepared according to the producer’s recipe, was from 5.9 to 23.2 μg/100 kcal, for special formulae from 3.7 to 35.4 μg/100 kcal, and for follow-on formulae from 10.7 to 25.6 μg/100 kcal. There is still a great need for stricter quality control of the iodine content in infant formulae.     

Effect of seasonal variations and lactation times on aflatoxin M1 contamination in milk of different species from Punjab, Pakistan

During October 2009 to September 2010, aflatoxin M₁ (AFM₁) levels were analyzed by HPLC-FLD in 356 milk samples of different lactating species (buffalo, cow, goat, sheep and camel) from Punjab (Pakistan). Recoveries of AFM₁ ranged from 92 to 97% and the limit of detection (LOD) was 0.004 μg/L. For all lactating species the mean concentration of AFM₁ was significantly higher in winter season than in summer (p < 0.05). The results showed that 55, 56, 32, 58 and 27% of winter milk samples of buffalo, cow, goat, sheep and camel exceeded the EU maximum limit (0.05 μg/kg), compared with 38, 33, 21, 36 and 14% of summer milk samples, respectively. For all lactating species the mean concentration of AFM₁ was significantly higher in morning milks than in evening milks (p < 0.05). The percentage of morning milk samples exceeding the EU maximum limit was 72, 67, 69, 71 and 44% for buffalo, cow, goat, sheep and camel, while for evening milks percent non compliant rates were 39, 30, 18, 33 and 25%, respectively. The level of AFM₁ tended to be higher in animal species fed mainly on concentrate mixtures (buffalo and cow) than in other species grazing on fresh greens.