Inexpensive,rapid screening method for aflatoxins in peanuts and peanut products

Surveys of major Brazilian foodstuffs demonstrated that peanuts and peanut products continue to be very susceptible to aflatoxin contamination. To prevent, or at least minimise, the problem the aflatoxins need to be monitored by a rapid and inexpensive screening method. The AOAC Romer method has been used and found highly reliable. However, the clean-up step utilises anhydrous FeCl₃ and basic CuCO₃ which are expensive and not readily available in Brazil. Thus, the extraction (with a mixture of 270 ml methanol plus 30ml 40 g litre^?1 aqueous KCl) and clean-up (150 ml 100 g litre^?1 aqueous CuSO₄) steps of the method of Soares and Rodriguez-Amaya (1985) were combined with the AOAC minicolumn to provide a rapid, inexpensive screening technique. Fifty-two sample lots of peanuts and peanut products were screened by this and Romer's method, and the results were in complete agreement: 28 samples were negative, four < 20 μg kg^?1, 12 in the range 20–50 μg kg^?1, three in the range 50–100 μg kg^?1 and 5 >100 μg kg^?1. The results also agreed well when the extracts obtained by the two methods were submitted to quantitative TLC.     

The occurrence of aflatoxins in mustard and mustard products

Natural occurrence of aflatoxins at concentrations of 750, 87 and 1420 micrograms/kg was recorded in 44, 33 and 80 samples out of 100 samples each of seeds, oil and cakes of mustard respectively. Out of 17 species of fungi isolated from mustard seeds, percentage incidence of the Aspergillus flavus group was maximum during monsoon and summer. Twenty-five per cent of isolates (out of 1143 isolates screened) of the A. flavus group were toxigenic, producing different components of aflatoxins in varying concentrations.     

Survey for aflatoxins, ochratoxin A, zearalenone and fumonisins in maize imported into the United Kingdom

This survey examined 140 samples of raw maize as received at ports or at major maize mills in the UK and 12 after initial cleaning. Samples were examined for aflatoxins B₁, B₂, G₁ and G₂, ochratoxin A, zearalenone and fumonisins B₁, B₂ and B₃ using fully validated analytical HPL C methods with detection limits of 0.1 mu g/kg for each aflatoxin and ochratoxin A, 4 mu g/ kg for zearalenone and 10 mu g/kg for each fumonisin. 95.0% and 92.1% of samples met the new EC statutory maximum permissible level for total aflatoxins and aflatoxin B₁ respectively. The maximum concentration of ochratoxin A found was 1.5 mu g/kg. Zearalenone and fumonisins were detected in almost every sample with 41.7% of maize containing more than 100 mu g/kg of zearalenone and 48% of samples containing more than 1000 mu g/kg total fumonisins. Initial cleaning of raw maize reduced aflatoxin concentrations by about 40% and total fumonisins by 32%.     

Natural occurrence of aflatoxins in Korean meju

Aflatoxin B₁ (AFB₁) was found in 35 of 60 (58.3%) meju samples with an average concentration of 7.3ng/g by ELISA. Contamination of AFB₁ was confirmed in 25 of 60 samples (41.6%) using HPLC, with an average concentration of 6.9ng/g. Mean recoveries from meju ranged from 107% to 170% for AFB₁ using ELISA at a spiking range of 1 to 50ng/g. Over the same range, recoveries using HPLC were from 70% to 83%. The levels of AFB₁ determined by ELISA and by HPLC demonstrated a close relationship between the two methods (r2 = 0.9324) employed in this study. In order to evaluate the potential health risks of AFB₁ on Koreans consuming meju, we calculated the estimated probable daily intake (PDI) based on the average contamination levels and compared it with the estimated tolerable daily intake (TDI). The PDIs of AFB₁ from kanjang and dwenjang were determined to be 0.04 and 0.21ng/kg bw/day, respectively, and were higher than TDIs.     

Co-occurrence of fumonisins with aflatoxins in home-stored maize for human consumption in rural villages of Tanzania

This study determined maize-user practices that influence the presence of fumonisin and aflatoxin contamination of maize in food consumed in the rural areas of Tanzania. Samples of the 2005 maize harvest in Tanzania were collected from 120 households and examined for fumonisins and aflatoxins. Information on whether the maize was sorted to remove defective (visibly damaged or mouldy) maize before storage and whether the damaged and mouldy maize or the non-dehulled maize was used as food was also collected. In addition, the percentage of defective kernels in the samples was determined. Ninety per cent of the households sorted out defective maize, 45% consumed the defective maize and 30% consumed non-dehulled maize. In 52% of the samples fumonisins were determined at levels up to 11,048 µg kg^?1 (median = 363 µg kg^?1) and in 15% exceeded 1000 µg kg^?1; the maximum tolerable limit (MTL) for fumonisins in maize for human consumption in other countries. Aflatoxins were detected in 18% of the samples at levels up to 158 µg kg^?1 (median = 24 µg kg^?1). Twelve per cent of the samples exceeded the Tanzanian limit for total aflatoxins (10 µg kg^?1). Aflatoxins co-occurred with fumonisins in 10% of the samples. The percentage defective kernels (mean = 22%) correlated positively (r = 0.39) with the fumonisin levels. Tanzanians are at a risk of exposure to fumonisins and aflatoxins in maize. There is a need for further research on fumonisin and aflatoxin exposure in Tanzania to develop appropriate control strategies.     

Detection of moulds producing aflatoxins in maize and peanuts by an immunoassay

An enzyme-linked immunosorbent assay (ELISA) was developed to detect moulds producing aflatoxins in maize and peanuts by an antibody produced to extracellular antigen from Aspergillus parasiticus. This antibody recognized species with phenotypic similarities to A. parasiticus, A. flavus and the domesticated species A. sojae and A. oryzae. For maize samples that were naturally contaminated with aflatoxins, low and high levels of aflatoxin corresponded with low and high ELISA readings for mould antigens, respectively. Maize and peanuts inoculated with 10(2) spores ml(-1) of A. parasiticus and incubated at 15 degrees C for 18 days or 21 degrees C for 7 days were analyzed for mould antigens and aflatoxin levels. At 15 degrees C, mould antigens were detected by day 4 in maize when 0.16 ng g(-1) of aflatoxin was detected by ELISA but not by thin layer chromatography (TLC). Antigens were detected in peanuts by day 4 before aflatoxin was found. Likewise, at 21 degrees C, antigens were detected by day 4 in maize when less than 1 ng g(-1) of aflatoxin was detected by ELISA but not by TLC, but by day 2 in peanuts when no aflatoxin was detected. A. parasiticus could be detected before it could produce aflatoxins. Therefore, this ELISA shows potential as an early detection method for moulds that produce aflatoxins.     

Occurrence of aflatoxins in peanuts, milk, and animal feed in Trinidad

The prevalence of aflatoxin B1 (AFB1) in 186 peanut products (140 peanuts, 32 peanut butter, and 14 nut cakes) from supermarkets, road vendors, and sale outlets, and 40 feed samples from dairy farmers was determined using the radioimmunoassay method (Charm II) test for aflatoxins. The frequency of aflatoxin M1 (AFM1) was also determined in 175 raw milk samples from milk collection centers and 37 pasteurized milk samples obtained from supermarkets and sale outlets. Overall, from a total of 438 samples tested, 18 (4.1%) were positive for aflatoxin comprising 5 (2.2%) of 226 peanut products and feeds positive for AFB1, and 13 (6.1%) of 212 milk samples positive for AFM1. All 186 peanuts and peanut products were negative (0.0%) for AFB1 while 5 (7.4%) of 40 dairy feed samples were positive. Of the 175 raw milk samples tested, 13 (7.4%) were contaminated with AFM1 while all pasteurized milk samples were negative. The detection of AFB1 in feed and AFM1 in milk is of public health importance considering the practice of raw milk consumption by the farmers and their families in the country.     

Efficacy of ozone as a fungicidal and detoxifying agent of aflatoxins in peanuts

BACKGROUND: Peanut contamination by fungi is a concern of processors and consumers owing to the association of these micro‐organisms with quality deterioration and aflatoxin production. In this study the fungicidal and detoxifying effects of ozone on aflatoxins in peanuts was investigated. Peanut kernels were ozonated at concentrations of 13 and 21 mg L^?1 for periods of 0, 24, 48, 72 and 96 h. RESULTS: Ozone was effective in controlling total fungi and potentially aflatoxigenic species in peanuts, with a reduction in colony‐forming units per gram greater than 3 log cycles at the concentration of 21 mg L^?1 after 96 h of exposure. A reduction in the percentage of peanuts with internal fungal populations was also observed, particularly after exposure to ozone at 21 mg L^?1. A reduction in the concentrations of total aflatoxins and aflatoxin B1 of approximately 30 and 25% respectively was observed for kernels exposed to ozone at 21 mg L^?1 for 96 h. CONCLUSION: It was concluded that ozone is an important alternative for peanut detoxification because it is effective in controlling potentially aflatoxigenic fungi and also acts in the reduction of aflatoxin levels in kernels. Copyright © 2011 Society of Chemical Industry     

The effect of village processing techniques on the content of aflatoxins in corn and peanuts in Zambia

The effect of village processing techniques on the aflatoxin content of corn and peanut products was investigated. In 30 trials, corn kernels were dehulled (bran removal), soaked for 24 h, washed and dried before grinding into flour and boiling in water to a thick consistency (Nshima). Shelled peanuts were either dry-roasted as whole kernels or ground into peanut meal and cooked. Dehulling, following by 24-h soaking (steeping) and subsequent washing significantly (P<0·05) reduced the aflatoxin B₁ content of corn flour from 900 to 150 μg kg⁻¹, and similarly that of aflatoxin G₁ from 929 to 114 μg kg⁻¹. Preparation of Nshima did not result into a substantial reduction in aflatoxin content, neither did extension of the cooking duration of 2 h afford any further decontamination. Whereas boiling peanut meal yielded a moderate reduction in the content of aflatoxins B₁ and G₁, roasting whole peanut kernels greatly reduced (P<0·001) the concentrations of the toxins from that in raw kernels (AFB₁= 8600 μg kg⁻¹ and AFG₁=6200 μg kg⁻¹) to 1300 and 1200 μg kg⁻¹, respectively. These results indicate that specific processing techniques carried out in Zambian villages are effective in reducing aflatoxin carry-over into edible fractions, while others are not. © 1998 SCI.     

Toxic metals (Hg, Cd, and Pb) in fishery products imported into Italy: suitability for human consumption

Mercury, cadmium, and lead concentrations were determined in various fishery products (fishes, cephalopod molluscs, and crustaceans) imported into Italy from many European and non-European coastal countries. Considerable differences were found in the concentrations of these metals among the products tested. The highest mean Hg concentration was found in fishes (0.21 μg g(-1) wet weight), whereas cephalopods had the highest mean Cd concentration (0.35 μg g(-1) wet weight). Swordfish (0.80 μg g(-1) wet weight), longtail tuna (0.53 μg g(-1) wet weight), and thornback ray (0.52 μg g(-1) wet weight) had the highest concentrations of Hg, whereas maximum Cd concentrations were found in samples of common cuttlefish (0.85 μg g(-1) wet weight) and common octopus (0.64 μg g(-1) wet weight). The majority of the samples analyzed were in compliance with European Union legislation, except for a few cases. The calculated mean weekly intakes of Hg, Cd, and Pb through consumption of the fishery products tested were all below the legislated respective provisional tolerable weekly intakes. In general, the samples analyzed were considered safe to eat with regard to the metal concentrations found and the allowable intakes based on legislation. Nevertheless, the consumption of some species may be of significant importance for consumer health.     

RETRACTED ARTICLE: Assessment of aflatoxins in peanuts grown in the Pothohar area of Pakistan

Statement of Retraction

The following article has been retracted from publication in the Taylor & Francis journal, Food Additives & Contaminants: Part B:

M. Abbas, M. R. Asi, F. Anwar, T. Mahmood, A. M. Khan and T. Yaqub, Assessment of aflatoxins in peanuts grown in the Pothohar area of Pakistan, Food Additives & Contaminants: Part B, http://www.tandfonline.com/doi/full/10.1080/19393210.2013.820221. Version of record published online 26th July 2013.

The Editor of Food Additives & Contaminants: Part B and Taylor & Francis note that the policy of the journal is to consider only original material, and authors are required to make a warranty to the effect that articles are not under consideration for publication by any other journal. The article was published in good faith. Subsequently, it has become known that a similar article was submitted to and published in World Academy of Science, Engineering and Technology, Volume 69 (2012). As this is contrary to our stated policy, the article is hereby retracted and should not be cited.

It is Taylor & Francis policy that the Food Additives & Contaminants: Part B article be kept online, but also stating that the paper has been retracted, together with a link to this Retraction to ensure the integrity of the scientific record.     

Studies into the occurrence of some trichothecene mycotoxins in UK home-grown wheat and in imported wheat

A total of 199 UK home-grown wheat samples collected over three harvests (1980–82 inclusive) and 33 imported wheat samples were analysed for the presence of seven trichothecene mycotoxins (nivalenol, deoxynivalenol, fusarenon-x, neosolaniol, diacetoxyscirpenol, HT-2 toxin and T-2 toxin). Analysis was performed by a gas–liquid chromatographic method and positive results greater than 0.1 mg kg^?1 were confirmed by mass spectrometry. The only mycotoxin detected in any of the samples was deoxynivalenol (vomitoxin) which occurred in 32 out of 199 UK home-grown wheats at levels ranging from 0.02 to 0.40 mg kg^?1 and 23 out of 33 imported wheats at levels ranging from 0.02 to 1.32 mg kg^?1. Microbiological evidence suggests that the lower incidence and levels of deoxynivalenol in UK, other EEC and Western Canadian wheat compared with Eastern Canadian and Midwest US wheat may be caused by a geographical variation in the distribution of Fusarium species.     

Intake of aflatoxins through the consumption of peanut products in Brazil

To estimate daily intake of aflatoxins from peanut products consumed by the population of Paraná State (Brazil), 100 samples of peanut products were collected between July 2006 and April 2007. Aflatoxins were determined by an HPLC method with fluorescence detection. There was a 50% occurrence of aflatoxins (B₁, B₂, G₁ and G₂) in concentrations ranging from 0.5 to 113?ng?g^?1, with 13 samples with levels above 20?ng?g^?1. Intake was calculated for average and high adult consumers of peanut products and it was compared with provisional maximum tolerable daily intake (PMTDI). The estimated probable daily intake (PDI) for aflatoxin B₁ (AFB₁) varied from 0.6 to 10.4?ng?kg^?1?bw?day^?1, exceeding the PMTDI of 0.4?ng?kg^?1?bw?day^?1 for carriers of hepatitis B virus.     

Natural occurrence of aflatoxins and zearalenone in maize in Brazil. Part II

The levels of aflatoxins and zearalenone were determined in 328 samples of corn from the States of Santa Catarina, Minas Gerais, S?o Paulo, Paraná, Rio Grande do Sul and Espírito Santo by thin-layer chromatography; the samples were obtained from April 1985 through to March 1986. In 12.3% of these samples aflatoxin B1 was detected in concentrations that varied from 10 to 900 micrograms/kg (ppb); 18 samples showed levels above those tolerated by Brazilian legislation. Zearalenone was found in 4.5% of the samples analysed in concentrations that varied from 653 to 9830 micrograms/kg (ppb). The limit of detection of the method for the determination of zearalenone was 260 micrograms/kg (ppb) and the recovery was 100%.     

Limited survey for the occurrence of aflatoxins in cereals and poultry feeds from Rabat, Morocco

Fifty eight (58) samples of cereals for human consumption (20 corn flour, 17 wheat flour) and poultry feeds (n=21) purchased from popular markets of Rabat in Morocco were analyzed for aflatoxins (AF) by HPLC with immunoaffinity column (IAC) clean-up and fluorimetric detection. The incidence of AF in corn, wheat flour and poultry feeds was about 80, 17.6 and 66.6% respectively. High contamination levels were found in corn and poultry feeds samples. Levels of contamination of analyzed samples with AFB1 ranged from 0.23 to 11.2, 0.03 to 0.15 and 0.05 to 5.38 ng/g for corn, wheat and poultry feeds respectively. Results showed also that the contamination of 10% of samples of corn was higher than the limit set by EU regulations for AFB1 and total AF. This is the first report on the determination of AF in corn, wheat and poultry feeds from Morocco by HPLC and IAC.     

Survey on the occurrence of aflatoxins in rice from different provinces of Iran

Aflatoxins were surveyed in 256 rice samples taken from retail markets in different provinces of Iran during October 2007 and July 2008. A methanol/water (80?:?20,?v/v) mixture and an aflatoxin immunoaffinity column (IAC) were used for extraction and clean-up. Mycotoxins were determined using HPLC with fluorescence detection and post-column derivatization using a photo-ionization cell. Levels of contamination ranged 0.0–5.8?ng?g^?1 (mean, 1.4?ng?g^?1) and 0.1–6.3?ng?g^?1 (mean, 1.6?ng?g^?1) for AFB1 and total aflatoxins, respectively. AFB1 was detected in almost all samples. Results showed that 55 samples (21.5%) were contaminated with more than 2?µg?kg^?1 of AFB1, while seven samples (2.7 %) contained more than 4?µg?kg^?1 total aflatoxins. The calculated probable daily intake of AFB1 from rice for Iranians ranged 1.4–5.8?ng AFB1 per kg body weight per day for average consumers and, hence. exceeding the estimated provisional maximum tolerable daily intake.     

黄曲霉毒素检测方法研究进展

黄曲霉毒素主要是由黄曲霉和寄生曲霉产生的一类次级代谢产物,经常污染粮油原料及其制品,具有强致癌性.介绍了黄曲霉毒素毒性及一些国家和地区的残留限量标准;针对不同基质间组分存在较大差异,概述了液液萃取、超临界流体萃取、固相萃取及免疫亲和柱净化等样品前处理方法;同时对薄层色谱、高效液相色谱、酶联免疫吸附等测定黄曲霉毒素的方法、原理、应用及特点进行了综述;最后分析了黄曲霉毒素检测技术的发展趋势.     

Salmonella prevalence in seafood imported into Japan

A total of 353 samples of 29 types of seafood were tested for Salmonella prevalence and total microbial population. Salmonella enterica serotype Weltevreden was isolated from 2 of 47 black tiger prawn samples. The contamination levels of Salmonella were in a range of <30 to 40 most probable number per 100 g. In addition, one sample of black tiger prawns and two samples of white shrimp were positive for Salmonella invA gene on PCR assay. Although the mean aerobic bacterial count was greater than 4 log CFU/g in most of the sample types, those in the two Salmonella-isolated samples of black tiger prawn were 7.48 and 5.18 log CFU/g, respectively. These results indicate the possibility that shrimp and prawns contribute to foodborne infections. The improvement of seafood quality is an important issue, and the information on contamination by pathogens should be provided as feedback to the originating country, with the aim of increasing safety.     

The role of carotenoids in consumer choice and the likely benefits from their inclusion into products for human consumption

To the consumer, appearance is one of the most important attributes affecting choice of purchase. For food, colour is ranked alongside freshness as one of the main criteria governing selection.Naturally occurring carotenoid pigments, such as astaxanthin and canthaxanthin, may be applied in animal feed so that the resulting food products are appealing to the consumer. Whilst arguably, these pigments may be seen to be of cosmetic value, astaxanthin and canthaxanthin are both known to exert benefits on animal health and welfare. Evidence suggests that carry-over of these pigments into the human food chain could also be beneficial to human health too.