Occurrence of ochratoxin A in black pepper, coriander, ginger and turmeric in India

Ochratoxin A (OA) contamination of black pepper, coriander seeds, powdered ginger and turmeric powder was estimated using indirect competitive ELISA. Samples (1 g) were extracted with 0.5% potassium chloride (KCl) in 70% methanol (5 ml) and diluted subsequently to give two-fold to ten-fold step-wise dilutions in phosphate-buffered saline containing 0.05% Tween 20 and 0.2% bovine serum albumin (PBS-T BSA). For extracts from the spices analysed, ELISA estimates of OA concentrations were compared with those made by HPLC. All estimates were within 1-2 standard deviation of the ELISA values. More than 90% of OA added to spice samples was recovered from samples containing between 5 and 100 microg/kg OA. Extracts of OA-free spice samples contained substances that interfered with ELISA, presumably because of non-specific reactions. This effect was avoided by preparing all the test solutions in extracts of OA-free spice samples. In 126 samples obtained from retail shops, OA was found to exceed 10 microg/kg in 14 (in the range of 15-69 microg/kg) of 26 black pepper samples, 20 (in the range of 10-51 microg/kg) of 50 coriander samples, two (23 microg/kg and 80 microg/kg) of 25 ginger samples and nine (in the range of 11-102 microg/kg) of 25 turmeric samples. This is the first record in India of the occurrence of OA in what are some of the most widely used spices in Indian cooking.     

Validation data for HPLC/FLD determinations of ochratoxin A in red paprika and black pepper adopting a one-step clean-up procedure

Validation data for the determination of ochratoxin A (OTA) in two spice matrices, red paprika and black pepper, were obtained for samples prepared with a simplified single-step clean-up column. Extracts of finely ground samples of red paprika and black pepper were prepared and applied to a Mycosep® 229 Ochra clean-up column. The purified extract was then subjected to HPLC/FLD analysis. The relative standard deviation for repeatability (RSDr) of the method was 11.8% for red paprika and 9.9% for black pepper. The limit of detection (LOD) value (three times the noise) was estimated as corresponding to the response of an extract derived from a blank matrix (previously washed) and spiked at 1.0 µg kg^?1. The limit of quantitation (LOQ) (three times LOD) was 3.0 µg kg^?1. The performance of the one-step column clean-up procedure appears to be a suitable alternative to commonly used clean-up techniques and allows the precise determination of OTA in two complex matrices.     

Variations in antioxidant properties of strawberries grown in Brazilian savannah and harvested in different seasons

BACKGROUND: Strawberries are nutritive fruits and a source of antioxidants. We evaluated antioxidant properties of ‘Camino Real’ strawberries grown in the Brazilian savannah, harvested in different seasons. Analytical and meteorological data were analyzed by partial least squares regression. RESULTS: Fruits from May showed the lowest contents of total phenolics (1789.78 mg kg^?1 fresh weight (FW)), catechin (21.37 mg kg^?1 FW), quercetins (4.89 mg kg^?1 FW) and total ellagic acid (208.68 mg kg^?1 FW) and the lowest antioxidant activity by 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH) (11.39 mg Butylated hydroxytoluene (BHT) eq. g^?1 FW) and ferric reducing antioxidant power (FRAP) (22.01 mg ferrous sulfate eq. g^?1 FW) assays. Strawberries harvested in July presented the lowest concentrations of total (190.61 mg kg^?1 FW) and individual anthocyanins (73.88 mg kg^?1 FW and 5.96 mg kg^?1 FW for pelargonidin‐3‐glucoside and cyanidin‐3‐glucoside, respectively), but the highest contents of vitamin C (685.47 mg kg^?1 FW), DPPH (18.87 mg BHT eq. g^?1 FW) and FRAP (39.30 mg ferrous sulfate eq. g^?1 FW). The highest contents of free ellagic acid (26.11 mg kg^?1 FW), pelargonidin‐3‐glucoside (291.82 mg kg^?1 FW) and cyanidin‐3‐glucoside (11.84 mg kg^?1 FW) were found in strawberries from September. Rain in the previous 30 days to harvest influenced negatively many phenolics and antioxidant activity of strawberries harvested in May. In July, longer photoperiod and lower temperature at 30 days previous to harvest probably led to higher antioxidant activity and vitamin C. Increased photoperiod and temperature at the final stage of maturation seem to raise pigments and free ellagic acid in strawberries. CONCLUSION: It was possible to observe significant relationships among meteorological and antioxidant variables for strawberries grown in the Brazilian savannah. Copyright © 2011 Society of Chemical Industry     

The effect of chemical treatment on reduction of aflatoxins and ochratoxin A in black and white pepper during washing

The effect of 18 different chemicals, which included acidic compounds (sulfuric acid, chloridric acid, phosphoric acid, benzoic acid, citric acid, acetic acid), alkaline compounds (ammonia, sodium bicarbonate, sodium hydroxide, potassium hydroxide, calcium hydroxide), salts (acetate ammonium, sodium bisulfite, sodium hydrosulfite, sodium chloride, sodium sulfate) and oxidising agents (hydrogen peroxide, sodium hypochlorite), on the reduction of aflatoxins B(1), B(2), G(1) and G(2) and ochratoxin A (OTA) was investigated in black and white pepper. OTA and aflatoxins were determined using HPLC after immunoaffinity column clean-up. Almost all of the applied chemicals showed a significant degree of reduction on mycotoxins (p < 0.05). The lowest and highest reduction of aflatoxin B(1), which is the most dangerous aflatoxin, was 20.5% ± 2.7% using benzoic acid and 54.5% ± 2.7% using sodium hydroxide. There was no significant difference between black and white peppers (p < 0.05).     

Analysis of duplicate 24-hour diet samples for aflatoxin B1, aflatoxin M1 and ochratoxin A.

In the spring and autumn of 1994, a total diet study, in which 123 participants collected duplicates of their 24-hour diets, was carried out. The goal of this study was to determine the mass fractions of a number of analytes in these duplicate diets, so as to be able to establish oral daily intake values. After measurements were carried out for pesticides, PCBs, elements, sterols, nitrate and nitrite, and fatty acids, the duplicate diet study was concluded with analyses for aflatoxin M1, aflatoxin B1 and ochratoxin A. For this purpose a method of analysis was developed, that could simultaneously determine these mycotoxins at very low levels. The method involved chloroform extraction, liquid-liquid extraction, immunoaffinity cleanup and liquid chromatography. The method was supplemented with a procedure to confirm the identity of chromatographic peaks, assumed to represent aflatoxin M1, aflatoxin B1 and ochratoxin A. The method was in-house validated. Recoveries ranged from 68-74% for aflatoxin M1 (at spiking levels from 30-120 ng/kg, c.v. 7.6%), from 95-97% for aflatoxin B1 (at spiking levels from 50-200 ng/kg, c.v. 2.8%), and from 75-84% for ochratoxin A (at spiking levels from 150-600 ng/kg, c.v. 4.3%). Limits of quantitation (defined as signal/noise = 10) were estimated to be 24, 5 and 16 ng/kg lyophilised material for aflatoxin M1, aflatoxin B1 and ochratoxin A respectively. The newly developed method was used to analyse 123 samples of 24-hour diets. Aflatoxin M1 was detectable in 48% of the samples; the toxin contents remained below the limit of quantitation in all samples. Aflatoxin B1 could be detected in 42% of the samples; in 25% of the samples the levels were above the limit of quantitation. Ochratoxin A could be quantified in all samples. The analytical results were further processed to estimate levels of intake. Intake levels for the aflatoxins were very low, and could not reliably be established. The mean ochratoxin A intake was estimated to be 1.2 ng/kg body weight per day. This is well below the tolerable daily intake established by JECFA at 14 ng/kg body weight per day. The current dietary intake of ochratoxin A in the Netherlands is concluded to pose no appreciable health risk.     

The effect of chemical treatment on reduction of aflatoxins and ochratoxin A in black and white pepper during washing

The effect of 18 different chemicals, which included acidic compounds (sulfuric acid, chloridric acid, phosphoric acid, benzoic acid, citric acid, acetic acid), alkaline compounds (ammonia, sodium bicarbonate, sodium hydroxide, potassium hydroxide, calcium hydroxide), salts (acetate ammonium, sodium bisulfite, sodium hydrosulfite, sodium chloride, sodium sulfate) and oxidising agents (hydrogen peroxide, sodium hypochlorite), on the reduction of aflatoxins B₁, B₂, G₁ and G₂ and ochratoxin A (OTA) was investigated in black and white pepper. OTA and aflatoxins were determined using HPLC after immunoaffinity column clean-up. Almost all of the applied chemicals showed a significant degree of reduction on mycotoxins (p?<?0.05). The lowest and highest reduction of aflatoxin B₁, which is the most dangerous aflatoxin, was 20.5%?±?2.7% using benzoic acid and 54.5%?±?2.7% using sodium hydroxide. There was no significant difference between black and white peppers (p?<?0.05).     

黑胡椒和白胡椒精油抗氧化性能及清除自由基能力的比较

黑胡椒精油(BPEO)和白胡椒精油(WPEO)的抗氧化活性的测定是基于总体抗氧化能力、清除超氧阴离子自由基能力、清除羟基自由基能力、铁离子还原能力、抗亚油酸脂质过氧化能力五个方面,并与其他的合成抗氧化剂如BHT,PG,Vc做比较.实验结果表明,在一定浓度范围内,黑、白胡椒精油清除超氧阴离子自由基的能力强于BHT、PG和Vc;被测样品的羟自由基清除率BHT>BPEO>WPEO>PG>Vc,精油能有效抑制亚油酸的过氧化反应.实验表明黑、白胡椒精油都具有良好的抗氧化效果,且黑胡椒精油强于白胡椒精油.     

Simultaneous determination of aflatoxin B1 and ochratoxin A and their natural occurrence in Mediterranean virgin olive oil

Olive oil, the most important dietary fat source of the Mediterranean diet, can be contaminated by mycotoxins. An efficient analytical method for the simultaneous determination of aflatoxin B₁ (AFB₁) and ochratoxin A (OTA) in olive oil is reported. Thirty commercial samples of virgin olive oil, purchased in olive-press plants and supermarkets in southern Italy and North Africa, were analysed to verify the analytical procedure and monitor mycotoxin contamination. A simple, rapid and economic method was set up and tested for both the extractive step and the clean-up procedures for simultaneous AFB₁ and OTA determination in olive oil. Data obtained showed that OTA was detected with high frequency (80%) in samples from both geographical areas (up to 17.0 ng g^-1), while AFB₁ was found from three of four samples from North Africa (up to 2.4 ng g^-1). In addition, 'not labelled' oil samples proved to be more contaminated by OTA then 'labelled' samples (mean values of 2.47 and 0.66 ng g^-1, respectively). These findings indicate that olive oil can be significantly contaminated by mycotoxins and confirm that a scrupulous application of European Regulation 1019/2002 (European Commission 2002), which prohibits the sale of non-labelled olive oil, is strongly recommended. Conventional qualitative parameters such as peroxide number, spectrophotometric evaluation and acid values were not correlated with mycotoxin occurrence.     

Effect of aflatoxin,ochratoxin and their combination on protein and energy utilisation in white leghorn laying hens

The effect of dietary aflatoxin B₁ (AF) at levels of 0.5, 1 and 2 mg kg^?1, ochratoxin A (OA) at levels of 1, 2 and 4 mg kg^?1 and their corresponding combinations on protein and energy utilisation as well as energy partitioning was studied in white leghorn laying hens. Protein retention was adversely affected at all levels of AF and OA either singly or in combination, though the effect was more evident with OA and AF + OA. Minimum protein retention was recorded in hens fed the combination of toxins at their highest levels (2 mg kg^?1 AF + 4 mg kg^?1 OA). Aflatoxin at 1 and 2 mg kg^?1 and OA and AF + OA at all levels caused a significant reduction in metabolisable energy (ME) value of the diets. The minimum ME value was recorded for the diet containing both toxins at their highest levels (2 mg kg^?1 AF + 4 mg kg^?1 OA). A significant depression in egg energy deposition was observed with dietary inclusion of 1 and 2 mg kg^?1 AF, 2 and 4 mg kg^?1 OA and all levels of AF + OA in period I. In period II the reduction in egg energy deposition was significant at all levels of toxins either singly or in combination. Body energy deposition was adversely affected in hens fed the highest levels of AF (2 mg kg^?1) and OA (4 mg kg^?1) and all levels of AF + OA in period I. However, in period II a significant decrease in body energy deposition was observed at all levels of toxins except 1 mg kg^?1 OA. A significant increase in maintenance energy (ME_m/W^0.75 day^?1) requirement was recorded in hens fed 2 mg kg^?1 AF, 4 mg kg^?1 OA and all levels of AF + OA. It is suggested that AF and OA either singly or in combination affect not only protein and energy utilisation in laying hens but also energy partitioning i.e. egg and body energy deposition and maintenance energy requirement. However, the combination of toxins (AF + OA) has more severe adverse effects on all parameters than the individual toxins because of their synergistic toxicity effect. Copyright © 2007 Society of Chemical Industry     

Study of aflatoxin B1 and ochratoxin A production by natural microflora and Aspergillus parasiticus in black and green olives of Greek origin

Aflatoxin B1 (AFB1) is a carcinogenic metabolite produced by certain Aspergillus species. Ochratoxin A (OTA) is classified as "possible carcinogen" and it is a metabolite of Aspergillus ochraceus and Penicillium verrucosum. Fungi contaminate natural and processed olives which support AFB1 and OTA production. The aim of this study was to compare and investigate AFB1 and OTA production in three different varieties of damaged olives. For each variety two different treatments were applied: (1) olives with natural microflora and (2) olives inoculated with A. parasiticus after natural microflora elimination. AFB1 and OTA have been extracted simultaneously from olives, purified with immunoaffinity columns and quantitated by HPLC using fluorescence detector. The recoveries and detection limits of AFB1 and OTA were 94% and 0.15 ng AFB1 g(-1) and 102.7%, 0.41 ng OTA g(-1) respectively. Results showed that, meanwhile OTA was not found in any olive sample, AFB(1) production within the three varieties of olives with natural microflora was significantly (P< or =0.05) different regarding their substrate and time of incubation (18 days). AFB1 production in two different varieties of black olives after inoculation by A. parasiticus was not significantly higher compared with control samples. On the contrary, AFB1 production in green olives was stimulated after the 12th day. Additionally, investigation on the occurrence of AFB1 and OTA in 30 samples of olives and olive pasta from Athens market showed OTA's presence in two samples of olives contaminated at the levels of 1.18 and 1.86 ng OTA g(-1). Aflatoxin B1 was found at levels 0.15-1.13 ng AFB1 g(-1) in all samples tested.     

Survey for co-occurrence of ochratoxin A and aflatoxin B1 in dried figs in Turkey by using a single laboratory-validated alkaline extraction method for ochratoxin A

A survey was carried out to determine the co-occurrence of ochratoxin A and aflatoxin B1 in dried figs from Turkey. Samples from two seasons of crops (2003 and 2004) intended for export to the European Union and the 2004 crop obtained from the domestic Turkish market were analyzed. Affinity column cleanup methods were employed for determining separately ochratoxin A and aflatoxin B1, but for ochratoxin A an alkaline extraction procedure was employed (in contrast to the conventionally employed acidic extraction), which gave consistently higher toxin recovery. In-house validation of the ochratoxin A method gave a limit of detection of 0.15 ng/g and a limit of quantification of 0.5 ng/g with a repeatability of 5.8% in the range 5 to 10 ng/g (with a mean recovery of 94% for spiked samples). Positive results for ochratoxin A were confirmed by liquid chromatography-mass spectrometry. For the 2003 export figs (58 samples), 7 samples contained only aflatoxin B1, 2 samples contained only ochratoxin A, and 2 samples contained both toxins (with maximum concentrations of 35.1 ng/g for aflatoxin B1 and 13.0 ng/g for ochratoxin A). Similarly for the 2004 export figs (41 samples), 16 samples contained only aflatoxin B1, 4 samples contained only ochratoxin A, and 2 samples contained both toxins (with maximum concentrations of 20.6 ng/g for aflatoxin B1 and 26.3 ng/g for ochratoxin A). Of 20 retail samples of dried figs from Turkey, only one sample contained ochratoxin A (2.0 ng/g) and none were contaminated with aflatoxin B1. This survey revealed a 14 to 15% incidence of occurrence of ochratoxin A for 2 years, which is higher than previously reported.     

Long term administration of low doses of mycotoxins in poultry. 2. Residues of ochratoxin A and aflatoxins in broilers and laying hens after combined administration of ochratoxin A and aflatoxin B1

The effects of combined administration of ochratoxin A (OA) and aflatoxin B1 (AFB1) on the occurrence and the levels of residues of mycotoxins in poultry have been investigated. Male broilers and laying hens were fed from 14 days old with standard diets contaminated with 50 micrograms/kg OA and 50 micrograms/kg AFB1. Two groups of broilers and hens were withdrawn from contaminated feed at 37 and 88 days, respectively. At the time of sacrifice no significant lesions were found. Residues were compared with those found after administration of either toxin alone in former trials. Combined treatment resulted in higher content of OA in broiler livers (40 versus 5.0 micrograms/kg) and, to a lesser extent, in kidneys and skin, and of AFB1 in broiler liver and kidney (0.15 versus 0.02 microgram/kg and 0.40 versus 0.05 microgram/kg respectively). Laying hens showed smaller differences (0.20 versus 0.10 microgram/kg in liver and 0.32 versus 0.08 in kidneys). Withdrawal from treatment led to the almost complete disappearance of OA residues in broilers and in hens. These results show a synergistic effect of OA and AFB1, particularly in broilers.     

Preliminary data on the presence of mycotoxins (ochratoxin A, citrinin and aflatoxin B1) in black table olives "Greek style" of Moroccan origin

Many mould strains, in particular Aspergillus and/or Penicillium, are able to develop on olive and produce ochratoxin A (OTA) and/or citrinin (CIT) and/or aflatoxin B (AFB) after harvest, during drying and storage of olives. The development of fungi on olives is responsible for the reduction of nutritional quality of olive because they can disturb the synthesis of the fatty acids. OTA, CIT and AFB are particularly dangerous for health, inducing cancer of urinary tracts or liver carcinoma. In this study, ten olive samples bought at retailer and at supermarket in Morocco were analyzed for their OTA, CIT and AFB contents. These three mycotoxins were extracted simultaneously by a method based on solvent partition validated in-house, then separated by HPLC coupled to a fluorescence detector. All olive samples contain OTA ranging from LOQ to 1.02 microg/kg. Respectively, 50 and 25% from retailer and supermarket samples were contaminated by more than 0.65 microg/kg. In addition, 80% of olive samples contained CIT above LOD, and 100% of olive tested contained AFB above 0.5 microg/kg. As simultaneous presence of these toxins increases toxic risks, it is thus essential to have a good control of the conservation of olives after harvest.     

Essential oils: their antibacterial properties and potential applications in foods--a review

In vitro studies have demonstrated antibacterial activity of essential oils (EOs) against Listeria monocytogenes, Salmonella typhimurium, Escherichia coli O157:H7, Shigella dysenteria, Bacillus cereus and Staphylococcus aureus at levels between 0.2 and 10 microl ml(-1). Gram-negative organisms are slightly less susceptible than gram-positive bacteria. A number of EO components has been identified as effective antibacterials, e.g. carvacrol, thymol, eugenol, perillaldehyde, cinnamaldehyde and cinnamic acid, having minimum inhibitory concentrations (MICs) of 0.05-5 microl ml(-1) in vitro. A higher concentration is needed to achieve the same effect in foods. Studies with fresh meat, meat products, fish, milk, dairy products, vegetables, fruit and cooked rice have shown that the concentration needed to achieve a significant antibacterial effect is around 0.5-20 microl g(-1) in foods and about 0.1-10 microl ml(-1) in solutions for washing fruit and vegetables. EOs comprise a large number of components and it is likely that their mode of action involves several targets in the bacterial cell. The hydrophobicity of EOs enables them to partition in the lipids of the cell membrane and mitochondria, rendering them permeable and leading to leakage of cell contents. Physical conditions that improve the action of EOs are low pH, low temperature and low oxygen levels. Synergism has been observed between carvacrol and its precursor p-cymene and between cinnamaldehyde and eugenol. Synergy between EO components and mild preservation methods has also been observed. Some EO components are legally registered flavourings in the EU and the USA. Undesirable organoleptic effects can be limited by careful selection of EOs according to the type of food.     

Co-occurrence of aflatoxin B1, fumonisin B1, ochratoxin A and zearalenone in cereals and peanuts from C?te d'Ivoire.

This survey examined 30 samples of rice (n = 10), maize (n = 10) and peanuts (n = 10) from C?te d'Ivoire for aflatoxin B1, fumonisin B1 and zearalenone using immunoassays, and ochratoxin A using a validated HPLC method with fluorescence detection. In C?te d'Ivoire, as in other countries, several mycotoxins are present in the same commodities. These mycotoxins are from different structural families: aflatoxin B1, fumonisin B1, zearalenone and ochratoxin A, normally produced by fungal species from Aspergillus, Penicillium and Fusarium genera. Some samples contained four mycotoxins (86%). Four peanuts samples did not show ochratoxin A (14%), whereas they contained aflatoxin B1 concentrations above the EU regulatory limits. Concentrations of ochratoxin A, zearalenone and fumonisin B1 were low and may not cause problems per se; however, fears remain that the tolerable daily intake may be exceeded due to eating habits and synergistic effects could be important with the combination of several mycotoxins. Investigations in this direction are underway, together with isolation and characterization of the fungal species involved.     

Colonisation and aflatoxin formation by Aspergillus spp. on brown rices differing in endosperm properties

Aspergillus flavus Link and A. parasiticus Speare differed in sporulation and aflatoxin B₁ formation on 15 brown rices differing in starch properties and protein content. There was no significant correlation between the degree of spore formation by the fungi and the amount of aflatoxin they produced in the rice samples. Differences in sporulation and aflatoxin production were not correlated with the dimensions (weight and hardness) of brown rice nor with the protein content, alkali spreading value, amylose content and gel viscosity of milled rice. Aflatoxin B₁ was mainly concentrated in the bran layers. Histological examination revealed that the hyphae of A. flavus entered through cracks in the periderm and penetrated the endosperm.     

Exploiting the bioactive properties of essential oils and their potential applications in food industry

Food Science and Biotechnology - Fruits are an abundant source of minerals and nutrients. High nutritional value and easy-to-consume property have increased its demand. In a way to fulfil this...     

Pithecellobium jiringa legume flour for potential food applications: Studies on their physico-chemical and functional properties

Jering seeds are traditionally consumed as a legume in South-East Asia. In the present study, we evaluated the physico-chemical, functional and cooking properties of jering seed flour with a major aim to popularise this seed for development of new food products. The seed flour had high moisture (58.55%) and crude protein contents (14.19%). Results on the functional properties revealed significant differences in the protein solubility, which showed a decrease from pH 2 to pH 4, with high water absorption (2.83 ml/g) and oil absorption (1.83 ml/g) capacities. The emulsifying activity and stability of the seed flour was highest at 0.4 M (26.27% and 75.75%, respectively). Addition of carbohydrates (lactose, maltose and sucrose) decreased the least gelation capacity. Results of this study showed functional properties of jering seed flour to be dependent on the concentration, pH and ionic strengths, which can be suitably modified for development of new food products.