Occurrence of histamine in Brazilian fresh and canned tuna

Histamine was investigated in fresh and canned tuna in Brazil. Histamine was detected in fresh tuna (3.4%) from the wholesale market, as well as fresh (46.7%) and canned tuna (46.3%) from the retail market. The mean levels were 0.19, 1.30 and 4.41 mg/kg, respectively. Grated canned tuna contained higher levels compared to solid; canned tuna in oil contained more than in water and salt; grated tuna with tomato sauce contained the highest levels. Every sample was in compliance with world legislation. The post catching and commercialization practices of tuna are adequate, warranting good quality tuna.     

Occurrence of Ochratoxin A in Brazilian cocoa beans

In the present work studied the occurrence of Ochratoxin A (OTA) in dried beans from southern Bahia (Brazil) harvested in two periods of the year (early crop and harvest seasons) then fermented and dried under the sun. Nearly 92.5% of the cocoa samples presented OTA levels below the limits suggested by the European Community (2 μg/kg). The highest toxin content was found in fine and flavour cocoa beans harvested in the early crop. Ochratoxigenic species of the genera Aspergillus and Penicillium were isolated from the cocoa beans. Both harvesting time and production model influenced OTA content in cocoa. These results show that, according to the current world standards for Ochratoxin A levels, beans from southern Bahia give a good quality cocoa.     

Free and hidden fumonisins in Brazilian raw maize samples

Fumonisins are secondary metabolites produced primarily by fungi strains that belong to the genera Fusarium and Alternaria, which have been shown to be highly prevalent in maize crops. Some authors have documented the presence of hidden forms of fumonisins occurring in raw maize. This purpose of this study was to determine the occurrence of free and hidden fumonisins in raw maize. The concentrations of fumonisins in 72 naturally contaminated maize samples were analyzed using liquid chromatography coupled to mass spectrometry. The performance parameters of the method to determine free fumonisins forms (FB₁ and FB₂) and hydrolyzed fumonisins forms (HFB₁ and HFB₂) were evaluated using the standards from the Commission of the European Communities (Commission, 2002). The analytical methods employed fell within the established guidelines. The amount of total fumonisins measured based on the hydrolyzed forms (HFB₁ + HFB₂) was 1.5–3.8 times greater than the amount of free fumonisins (FB₁ + FB₂). The concentration of hidden fumonisins was calculated by subtracting the levels of free fumonisins from the total fumonisin levels. The levels of hidden fumonisins were calculated to be 0.5–2.0 times greater than the level of free fumonisins. A strong positive correlation (R = 0.97) was observed between free fumonisins (FB₁ + FB₂) and. total fumonisins (HFB₁ + HFB₂). Based on this correlation, a predictive model was generated to estimate the total fumonisin level based on the measured/reported free fumonisin concentration. These results show that the risk of exposure to fumonisins is likely underestimated if only free fumonisins are considered. However, the predictive model could be a novel approach to estimating the total amount of fumonisins in maize samples without needing to perform expensive and time-consuming analytical methods.     

Occurrence and legislation of mycotoxins in food and feed from Morocco

Mycotoxins are natural food and feed contaminants, mainly produced by moulds of genera Aspergillus, Penicillium and Fusarium. The number of mycotoxins known to exert toxic effect on human and animal health is constantly increasing as well as the legislative provisions taken to control their presence in food and feed. Morocco, a North African country, surrounded by the Mediterranean Sea and Atlantic Ocean, has a climate characterized by high humidity and high temperature which favor growth of moulds. This paper gives an overview about the contamination levels and the occurrence of some mycotoxins (e.g. aflatoxins, ochratoxin A, and Fusarium toxins) in cereals, bread, milk, spices, wine, olives, poultry feeds, dried fruits and nuts; the average of contaminated samples was often above 50%. A section on mycotoxin regulations by Moroccan authorities is discussed with a comparison with international and European limits. Recent data about the contamination of foods and feed from Morocco by mycotoxins are considered in this review. Finally, the paper gives a last part with conclusions and principal prospectives and recommendations that should be undertaken by authorities and scientists during monitoring of mycotoxins in food and feed produced and/or commercialized in Morocco.     

Occurrence of aflatoxin M1 in white cheese samples from Tehran, Iran

This study was undertaken to determine the occurrence of aflatoxin M₁ (AFM₁) in 50 white cheese samples from 2 dairy factories in summer 2008 and winter 2009. Enzyme-linked immunosorbent assay (ELISA) method was used for analysis of the samples. Aflatoxin M₁ was found in 60% of the cheese samples, ranging from 40.9 to 374 ng/kg. Toxin levels in 6% of the samples exceeded the Iranian national standard limit i.e. 200 ng/kg. Considering seasonal variability, mean concentration of AFM₁ in the samples collected in winter was significantly (P < 0.03) higher than those collected in summer. Therefore, high occurrence of AFM₁ in cheese samples could be a potential hazard for public health.     

Estimation of the daily intake of hexachlorobenzene from food consumption by the population of Catalonia, Spain: Health risks

In 2000 and 2006, we determined the dietary intake of hexachlorobenzene (HCB) by the population of Catalonia, Spain. In order to establish the temporal trend in the levels of HCB in foodstuffs, as well as in the dietary exposure to that environmental pollutant, the concentrations were again analyzed by HRGC/HRMS in 65 composite food samples widely consumed by the Catalan population. Food samples were randomly purchased in November-December 2008 in local markets, small stores, supermarkets, and large grocery stores from 12 representative cities from Catalonia. The daily intake of HCB associated with this consumption was estimated for four age groups of the population of Catalonia: children, teenagers, adults and seniors, which were in turn divided according to sex. The highest mean HCB levels in food were detected in oils and fats (0.297 ng/g fw), dairy products (0.225 ng/g fw), and fish and seafood (0.170 ng/g fw). In the 2000 and 2006 surveys, total dietary intakes of HCB were 166.2 and 71.6 ng/day, respectively (or 2.4 and 1.0 ng/kg of body weight per day). In the current study, it was 37.7 ng/day (or 0.54 ng/kg of body weight per day), which means considerable decreases with respect to the previous intakes. According to recommendations of international regulatory organisms, the current dietary intake of HCB should not mean any significant health risk (carcinogenic and non-carcinogenic) for any of the age/gender groups of population here assessed.     

Occurrence of ochratoxin A in cereal-derived food products commonly consumed in Turkey

Ochratoxin A (OTA) is a mycotoxin that can be found in several food commodities including cereals, wine, coffee, cacao, spices or dried fruits, resulting in chronic human exposure. The aim of our study was to investigate the presence of OTA in widely consumed cereal-derived products commercialized in Turkey. A total of 142 samples were collected from different supermarkets and traditional bazaars in Istanbul during 2008-2010 years. The analytical methods used in our study involved the liquid/liquid extraction of OTA, immunoaffinity clean-up and high performance liquid chromatography determination with fluorescence detection. The frequencies of OTA contamination were 21.62%, 19.05% and 55.95% and the mean concentrations of positive samples were 0.32 μg/kg, 0.14 μg/kg, 0.41 μg/kg for breakfast cereals, cereal-based baby foods and tarhana samples, respectively. Our findings show that contamination levels of OTA in all cereal-derived products were lower than the permitted level by European Commission Regulation.     

Occurrence of Listeria spp. in Brazilian fresh sausage and control of Listeria monocytogenes using bacteriophage P100

Since the 1980s, an increase in outbreaks of human listeriosis linked to contaminated food has been a concern of health authorities. Intensively manipulated foods, such as Brazilian fresh sausage, are frequently responsible for food-borne diseases. In this work the occurrence of Listeria monocytogenes and the efficacy of bacteriophage P100 (LISTEX?) to control the microorganism was evaluated in Brazilian fresh sausage. Eighty samples were analyzed, 40 each of swine and chicken Brazilian fresh sausage. Listeria spp. were isolated from 12 samples (15%), of which three (3.75%) were positive for L. monocytogenes. L. monocytogenes strains isolated belonged to serotype 1/2a. L. monocytogenes 1/2a was inoculated in Brazilian fresh sausage (2.1 × 10⁴ cfu/g) with the bacteriophage added thereafter (3.0 × 10⁷ pfu/g). Samples were analysed immediately (day zero) and then stored at 4 °C for 10 days. The bacteriophage P100 reduced L. monocytogenes counts by 2.5 log units at both 0 and 10 days compared to controls without bacteriophage. In spite of this, the populations of L. moncytogenes increased over the 10 day storage. Our data demonstrate that in one of the samples the use of the bacteriophage dropped the bacteria count below the level of direct detection. This study demonstrates a new alternative for pathogen control in the food industry, especially in the processes used to produce Brazilian fresh sausage.     

Occurrence of coagulase-positive Staphylococcus in various food products commercialized in Botucatu,SP, Brazil and detection of toxins from food and isolated strains

The aim of this work was to assess the microbiological quality of commercialized desserts, sandwiches and finger food in Botucatu, SP, for human consumption. A total of 172 food samples were analyzed for fecal coliforms and coagulase-positive Staphylococcus and 69 (40.1%) were in disagreement with the standards established by Decree No. 12 (Brazilian Food Sanitation Standard, 2001). Coagulase-positive Staphylococcus was isolated from 26 (15.1%) samples. Toxins were not isolated directly from foods but 27 (54%) coagulase-positive Staphylococcus strains were enterotoxigenic, and toxin type C was the most frequently detected. These results suggest that these products may act as an important vehicle of transmission for well-established pathogens.     

Analysis of aflatoxin M1 in milk and yogurt and AFM1 reduction by lactic acid bacteria used in Lebanese industry

In this study a screening survey was undertaken to determine the presence and levels of aflatoxin M1 (AFM1) in locally produced dairy products. For this purpose, a total of 138 dairy samples (milk and yogurt) were analyzed to quantify AFM1 levels in these products. Results obtained showed that AFM1 was found in 40.62% and 32.81% of milk and yogurt samples respectively. The range of contamination levels varied between lower and higher than European regulation limit. Lactic acid bacteria (Lactobacillus bulgaricus and Streptococcus thermophilus) used in the Lebanese traditional industry were screened for their ability to reduce the level of AFM1. Due to the lack in data on the natural occurrence of AFM1 in Lebanese dairy products, the aim of this work was to report some information and to state these products according to EC regulations     

Analysis of total aerobic viable counts in samples of raw meat using fluorescence-based probe and oxygen consumption assay

A simple test for determining total aerobic viable counts in raw meat is presented. Homogenates of meat samples are prepared in full PBW medium, dispensed in the wells of 96-well plate together with the oxygen-sensing probe, Redlight, covered with oil and monitored on a fluorescent reader at 30 °C. The probe produces characteristic sigmoidal profiles of fluorescence reflecting depletion of sample dissolved oxygen, with onset time indicating the initial microbial load. The test provides rapid and accurate results (1 and 12 h for contamination levels of 10⁸ and 10³ cfu/g, respectively) and correlates well with the ISO:4833:2003 method (r = 0.86), which make it useful as alternative to conventional culture methods for the quick, high throughput determination of TVC (30 °C) in meat samples.     

Occurrence of aflatoxin M1 in cheese processed and marketed in Lebanon

Aflatoxin M1 (AFM1) is the principal hydroxylated metabolite of aflatoxin B1 excreted in milk, and subsequently it can be found in a large variety of dairy products thus posing a potential risk to human health when consuming these products. Considering its significant impact on human health, determination of AFM1 levels in dairy products becomes imperative. The present study was undertaken to investigate, for the first time, the levels of AFM1 in various locally processed (halloumi, baladi, shelal, naboulsi, double cream, feta and akkawi) or imported (white and yellow) cheese types available in Lebanese markets. For this purpose a total of 111 cheese samples were randomly collected from local small dairy farms (53 samples), Lebanese leading dairy industries (38 samples) and imported cheeses (20 samples). Aflatoxin M1 was detected in 67.56% out of the 111 samples analyzed in which the levels of AFM1 in 17.33% of the samples were found to exceed the limits (250 ng/kg) allowed by European Commission (EC). Of the analyzed cheese samples, AFM1 levels in 13 cheeses from small local dairy farms were above the limits set by the EC ranging between 255 and 315 ng/kg. None of the cheese samples collected from the Lebanese leading dairy industries or from the imported types exceeded the permissible limit where the highest recorded levels were 77.2 and 3.95 ng/kg, respectively. The results of this study indicate that continuous monitoring of AFM1 levels in commonly consumed cheese in Lebanon should be regularly done. It also shows an alarming situation with respect to cheeses produced from local small farms.     

Occurrence of aflatoxin M1 in dairy products in Brazil

The objective of this study was to investigate the incidence and occurrence of aflatoxin M₁ (AFM₁) in dairy products produced in Brazil. A total of 123 samples of three different groups of dairy products (cheese, yoghurt, and dairy drinks) consumed by Brazilians were collected during 2010. All samples including 58 cheese samples, 53 samples of yoghurt and 12 dairy drinks were purchased from grocery stores in the Ribeirão Preto-SP area. Cheese samples were classified into three categories depending on their moisture and fat contents: Minas Frescal cheese, Minas Frescal light cheese and Minas Padrão cheese. Samples were analyzed for AFM₁ by a published method. The method comprised aqueous methanol extraction, immunoaffinity column purification and isolation, reversed phase liquid chromatography separation and fluorescence detection. AFM₁ was detected in 84% of the analyzed cheese samples (>3 ng/kg) with levels ranging from 10 to 304 ng/kg in 67% of the samples. AFM₁ was detected in 95% of the yoghurt and dairy drink samples with levels ranging from 10 to 529 ng/kg in 72% of the samples. Despite the lack of a Brazilian regulatory limit for AFM₁ in yoghurt and dairy drinks the survey data of this study may offer information useful in the determination of whether the occurrence of AFM₁ in Brazilian dairy products may be considered as a possible risk for consumer health and whether Brazilian regulatory guidelines for AFM₁ in dairy products are needed.     

Occurrence of aflatoxin M1 in UHT milk and pasteurized milk in China market

In the present study, the contamination of aflatoxin M1 (AFM1) in 153 UHT milk samples collected in July and September 2010, and 26 pasteurized milk samples collected in September 2010, were assessed using the ELISA method. The AFM1 was detected in 54.9% of UHT milk samples with a concentration of 0.006–0.160 μg/L. Moreover, 96.2% of pasteurized milk samples tested positive for AFM1 with concentration levels of 0.023–0.154 μg/L. The occurrence of AFM1 in all positive samples was far below China's national legal limit of 0.5 μg/L. Meanwhile, the AMF1 content in 20.3% of UHT milk samples and 65.4% of pasteurized milk samples exceeds the European Union's legal limit of 0.05 μg/L.     

Multiresidue determination of antibiotics in feed and fish samples for food safety evaluation. Comparison of immunoassay vs LC-MS-MS

Antibiotic residues (sulfonamides and tetracyclines) were determined in Gilthead sea bream (Sparus aurata) and feed samples by means of immunoassays and LC-MS-MS (liquid chromatography-mass spectrometry²). A preliminary study to know the withdrawal time of oxytetracycline in Gilthead sea bream samples was also conducted. It was carried out using immunoassays based on photometric detection of horseradish peroxidase (HRP) activity and time-resolved fluorometric detection of coproporphyrin of Platinum (II) (ELISA and TR-FIA, respectively). The results were compared to those obtained using an LC-MS-MS methodology. They showed that approximately 37 days would be the withdrawal time in order not to exceed the MRL and fish could be commercialized with safety.Regarding feed samples analysis, an LC-MS-MS method was optimized including sample treatment. Average recoveries (n = 6) ranging from 78 to 108% were obtained and precision of the method was between 0.2 and 3%. The same sample treatment was applied to the feed immunoanalysis obtaining satisfactory results.Finally, 20 fish and 4 feed samples were analysed in order to confirm the feasibility of the immunoassays for detecting antibiotic residues. Sulfonamide residues were not detected in any fish sample. Tetracycline residues were detected in some fish samples from marine farms, with total concentrations between 2.1 and 152 ng g^?1. In all cases, the obtained results correlated well with those achieved by LC-MS-MS. Therefore, the new methodology allows for food safety of the medicated fish.     

Survey of aflatoxin B1 in helva,a traditional Turkish food,by TLC

A total of 102 helva samples consisting of 34 plain helva, 34 helva containing cacao, and 34 helva containing pistachio nuts purchased from helva-factories and supermarkets in Adana of Turkey were analysed for aflatoxin B₁ (AFB₁) by thin-layer chromatography. The detection limit of AFB₁ was 1 μg kg⁻¹. Recovery experiments were carried out with spiked samples in the range 2–10 μg kg⁻¹ of AFB₁. No AFB₁ was found in any plain helva and helva containing cacao samples. On the other hand, of 34 helva containing pistachio nuts AFB₁ was determined in eight samples. AFB₁ was found in excess of Turkish legal limit of 5 μg kg⁻¹ in 4 of 102 helva samples. This paper reports the data of the first survey for the presence of AFB₁ in helva in Turkey.     

An ELIME-array for detection of aflatoxin B1 in corn samples

The aim of the present work was the development of an ELIME-array to achieve simple and rapid detection of AFB₁ in corn samples. The system is based on an indirect competitive ELISA format using magnetic beads as immobilisation support and eight magnetised screen-printed electrodes as electrochemical transducers.After an optimisation study, a corn sample treatment, employing an extraction in acetonitrile/water followed by a clean-up step and solvent evaporation, was selected.For the construction of the calibration curve, which was used to evaluate both evaluation of the matrix effect on the performances of the ELIME-array and for the analysis of Certified Reference Materials (CRMs), standard solutions of AFB₁ were added to blank dried corn extracts reconstituted in PBS. The detection limit and the sensitivity of the assay were calculated to be 0.6 ng mL^?1 and 1.5 ng mL^?1, respectively.Precision (11–26%) and recovery (95–114%) data of the ELIME-array, determined by analysing four CRMs, have shown that the proposed system appears suitable as a screening tool for the analysis of AFB₁ in corn samples.     

Occurrence of virulence factors and antibiotic resistances in Enterococcus faecalis and Enterococcus faecium collected from dairy and human samples in North Italy

The aim of this research was to study the incidence of potential virulence factors and antibiotic resistance in 38 Enterococcus faecalis and 43 Enterococcus faecium strains isolated from dairy products and human samples. The presence of the virulence factors agg, ace, esp, gelE, efaA and of the vanA and vanB genes was evaluated by PCR, while antibiotic resistance was tested by the disk diffusion method. Ent. faecalis displayed more virulence determinants than Ent. faecium, with the presence of multiple virulence traits. Virulence determinants were present in both human and dairy strains, while antibiotic resistance patterns of the two groups of strains were very different with a significant higher diffusion of resistances among human enterococci. Considering the results of our study, dairy enterococci cannot be considered the main potential source for dissemination of antibiotic resistances.