Imagine an editor of a scientific journal was impressed by your group presentation and invited you to write a literature review based on your group presentation content

Imagine an editor of a scientific journal was impressed by your group presentation and invited you to write a literature review based on your group presentation content. The editor told you that the length of the review should be between 900- 1100 words (not including the reference list) and the review should follow APA citation format.

Number of references to be included into this writing: at least 4 references.

Topic: Molds (mycotoxins) in foods and the environment. The final written report will be organized as follows: Cover page + 4-5-page writing (900-1100 words, typed double-spaced) + reference page Cover page: descriptive title + your name. 1. Introduction A brief introduction to the chemical(s) of interest; the health effect you researched; the significance of this topic. Don’t forget to include in-text citations (if needed). Don’t forget to state the purpose of this final report (e.g. “This report is to review….”). 2. Body a. Subtopic 1 (How molds (mycotoxins) occur). What is the question (or controversy)? What are your findings? Summarize each study. Do the results of the study (studies) answer the question? Is there any limitation of the study (studies)? (Remember to include in-text citations) b. Subtopic 2 (Adverse health effects). What is the question (or controversy)? What are your findings? Summarize each study. Do the results of the study (studies) answer the question? Is there any limitation of the study (studies)? (Remember to include in-text citations) 3. Conclusion The overall conclusion of the report. What do we learn after reviewing the above studies? You may also include recommendations /regulations, future research directions of this topic, etc. (If regulations come from government websites, include the websites into your in-text citations and into the reference list). Reference page List all references (For each reference, make sure you list the followings: authors, year, title of reference, title of periodical, volume number (issue number), page number). See discussions, stats, and author profiles for this publication at: https://www.researchgate.net/publication/234023849 Occurrence of fungi and mycotoxins in some some commercial baby foods in North Africa Article in Journal of Food Science and Nutrition · January 2011 CITATIONS READS 7 106 5 authors, including: Kofi Aidoo Richard F. Tester Glasgow Caledonian University Glycologic Limited 68 PUBLICATIONS 1,783 CITATIONS 113 PUBLICATIONS 7,695 CITATIONS SEE PROFILE Some of the authors of this publication are also working on these related projects: Carbohydrate based therapeutics View project Carbohydrate based therapeutics View project All content following this page was uploaded by Kofi Aidoo on 02 June 2014. The user has requested enhancement of the downloaded file. SEE PROFILE 751 Food and Nutrition Sciences, 2011, 2, 751-758 doi:10.4236/fns.2011.27103 Published Online September 2011 (http://www.SciRP.org/journal/fns) Occurrence of Fungi and Mycotoxins in Some Commercial Baby Foods in North Africa Kofi Edirisah Aidoo1*, Shadlia Matug Mohamed1,3, Alan Alexander Candlish1, Richard Frank Tester1, Ali Mohamed Elgerbi2 1 School of Biological and Biomedical Sciences, Glasgow Caledonian University, Glasgow, UK; 2Department of Food Technology, Sebha University, Faculty of Engineering and Technology, Brack Ashati, Libya; 3Present address: Renewable Energies and Water Desalination Research, Center, Tajoura, Libya. Email: *K.Aidoo@gcu.ac.uk Received February 14th, 2011; revised July 21st, 2011; accepted July 28th, 2011. ABSTRACT Aflatoxins, are one of over 200 known mycotoxins produced by filamentous fungi. They are toxic, carcinogenic, and mutagenic and may be present in many raw and processed food commodities including cereals and milk used as ingredients in infant food products. Consumption of these commodities may pose a potential risk to the health of infants. The mycoflora of 84 samples of baby food commercially available in North Africa was determined. The feeds were screened for mycotoxins using thin layer chromatography (TLC) and further analyses were carried for the total aflatoxins by high performance liquid chromatography (HPLC) using a Kobra cell to derivatise the aflatoxins (B1, G1, B2 and G2). Twenty-four fungal isolates were recovered from the samples consisting of 5 Aspergillus. spp, 13 Penicillum. spp, 5 Mucor. spp and an unidentified species Of these, 45.8% of the isolates were found to be mycotoxigenic however only 2.4% of the samples contained aflatoxins (19 to 70 µg·kg–1) and the remaining contained undetectable levels of the toxin. Storage at elevated relative humidity for 7 days showed a slight increase in the fungal counts but the toxin levels were unaffected. The results show the importance of periodic testing regime of ingredients used infant food formula for the presence of fungal contamination. Keywords: Mycotoxins, Aflatoxins, HPLC, Infant Food, North Africa 1. Introduction Powdered infant formula and feed products have been associated with serious illness and death in infants due to microbial infections, in particular pathogenic bacteria. Cereals, dairy products, fruits and nuts are some of the materials used in the formulation of baby food. Baby food and feed formula can be contaminated with microorganisms through inadequate manufacturing process. During the preparation of infant formula, inappropriate handling practices can exacerbate the problem. The FAO/WHO, European Commission and Food and Drug Administration have set permissible levels for total bacterial counts in infant food and formula, however there is very information on levels of fungi in such products. Agricultural products may become contaminated with fungi during drying and storage. The FAO estimates that mycotoxins contaminate 25 percent of agricultural crops worldwide [1]. Mycotoxins are produced by various strains of fungi, Copyright © 2011 SciRes. particularly Penicillium, Aspergillus and Fusarium. Mycotoxins are well known as a worldwide health problem particularly in countries with high ambient temperature and relative humidity typical of tropical countries [1-3]. A great deal of attention has been given to aflatoxigenic fungi such as Aspergillus flavus and A. parasiticus. Of the aflatoxins, aflatoxin B1 (AFB1) is considered by the International Agency for Research on Cancer [4] to be the most carcinogenic. About 250,000 hepatocellular carcinoma related deaths are reported to occur annually in Africa due to aflatoxin ingestion where 80% of cases and deaths of liver cancer occur in Western and Central Africa [5,6]. The carcinogens may be present in many raw and processed foods and feeds. Among these products, cereals and milk are very susceptible to mycotoxin contamination and are often used as ingredients in many infant food products [7-10]. Consumption of foods produced from these commodities may pose a potential risk to the health of the infants since the toxins are resistant to various food processes, including heat treatment [11-14]. FNS 752 Occurrence of Fungi and Mycotoxins in Some Commercial Baby Foods in North Africa Regulations to control the mycotoxin content of foods have been established in about one hundred countries, out of which fifteen are African, to protect the consumer [15-17]. The European Community and Codex Alimentarius have set a maximum level of total aflatoxin (AF) exposure in infant foods, AFB1 and aflatoxin M1 (AFM1) at level 0.04 µg·kg–1, 0.02 µg·kg–1 and 0.025 µg·kg–1 respectively [18,19]. Most African countries have a climate characterised by high humidity and high temperature which favours the growth of fungi in food products, and therefore the potential for the production of mycotoxins. Hence, there is a need to investigate the occurrence of aflatoxins in infant foods since some of the ingredients used in the foods are usually prone to fungal contamination. The objective of the present work was to determine the mycoflora of a range of commercial baby foods, evaluate toxigenic capability of the isolates and the effect of storage conditions on the samples. Natural occurrence of aflatoxins in the samples was also determined. It is anticipated that the results from this study would help to understand the general mycoflora and potential mycotoxins which may be present in infant food and feed formulae retailed in North Africa. 2. Materials and Methods 2.1. Mycological Examination of Infant Food Samples Eighty-four samples of baby food were collected from several local sources including retailers, factories and stores in Libya. The ingredients of the samples comprised of rice flour, wheat flour, mixed grain cereal, wheat, rice, barley, and oat flour, skimmed milk powder or whole milk powder and in various combinations. The samples were examined for mycological profile before storage at 22?C and 80% relative humidity in humidity chamber (Cryotechnics, 2000 Series, Edinburgh, UK) for 7 days. Standard methods were used for isolation, enumeration and identification of fungi [20]. Samples were reconstituted in maximum recovery dilutent (MRD, Oxoid, Basingstoke, UK) and plated out on malt extract agar (MEA, VWR International, Lutterworth, UK) and potato dextrose agar (PDA, Oxoid CM 139). The plates were then incubated at 25?C for 5 days. cutting the fungal colony to a diameter of 5 mm. The plugs were immersed in 2 mL of methanol for extraction of toxin from fungi and culture medium centrifuged (Stuart 2500 RMP) at 2500 rpm for 30 s. The extracts (10 μL) were spotted on TLC plates (20 ? 20 cm, Merck) coated with 0.25 mm thin layer of silica gel. Subsequently, 10 μL of mycotoxin standard solutions total aflatoxins, ochratoxin A (Biopharm, Glasgow, UK) and citrinin (Sigma-Aldrich, Dorset, UK) were used as reference standards (40 μg·mL–1) and spotted along with the fungal samples extract. The plates were developed in a solvent tank containing toluene—ethyl acetate—formic acid (5:4:1) for 1h and viewed under long wave UV light (365 nm). Sample extracts were compared with reference standards spots. 2.3. Detection of Aflatoxins in the Samples by High Performance Liquid Chromatography Technique (HPLC) 2.3.1. Sample Extraction and Preparation Food samples (50 g) were extracted using 250 mL of methanol/water (60/40, v/v) containing 4 g NaCl and homogenised for 1min using a high speed homogeniser. Distilled water (250 mL) was added and this extract was filtered through a Whatman No 4 filter paper (55mm) and the filtrate collected. The filtrate was then analysed by passing 10 mL through an immunoaffinity column followed by 10 mL distilled water (twice) to remove any interfering material. Aflatoxins were eluted by passing 1 mL of acetonitrile through the column. The stock solution and standards were prepared and determined as described by the manufacturer and Candlish et al. [22]. Quantitative analysis was conducted on all samples by injection of 100 µL extract through the HPLC system and using total aflatoxins (AFs) as standards (Biopharm Rhone, Glasgow, UK). 2.2. Thin Layer Chromatography (TLC) Assay 2.3.2. Preparation of Artificially Contaminated Sample Infant food samples free of aflatoxins (AFs) were artificially spiked with 10 ng of AFs/g (in triplicate) and extracted as above and then passed a known volume of sample through an immunoaffinity column. Recovery of aflatoxins (AFs) from immunoaffinity columns was expressed as a percentage of aflatoxins detected by HPLC compared to the known concentration of aflatoxins added to the 10 ml sample filtrate. Twenty five fungal strains isolates were grown on malt extract agar (MEA, VWR International, Lutterworth, UK) and potato dextrose agar (PDA, Oxoid CM 139), the culture plates were incubated at 25?C for 7 days and examined for mycotoxins using the TLC technique as reported by others [20,21]. Agar plugs were prepared by 2.3.3. Chemicals, Reagents and HPLC Conditions Acetonitrile and methanol were purchased from Fisher Scientific (Loughborough, UK). Aflatoxin standard solutions and immunoaffinity columns (Aflaprep®) were purchased from R-Biopharm Rhone Ltd (Glasgow, Scotland). The HPLC system consisted of a pump (Wellchrom Copyright © 2011 SciRes. FNS Occurrence of Fungi and Mycotoxins in Some Commercial Baby Foods in North Africa K 1001 Knauer) and a fluorescence detector (Waters 470, UK) combined with a Kobra cell® (R-Biopharm Rhone Ltd, Glasgow) as an electrochemical reaction cell. The mobile phase consisted of water-acetonitrile-methanol (60: 20:20, v/v/v) with 350 µL of 4 M nitric acid and 119 mg of potassium bromide per litre and flow rate of 0.8 mL/min for aflatoxins detection in both the standard and the extracts from the baby food samples. Aflatoxins were derivatised in the Kobra cell and later detected at λex = 366 nm, λem = 465 nm. The aflatoxins B1, B2, G1 and G2 were detected by HPLC and the four peaks quantified. 2.4. Statistical Analysis All tests were conducted in triplicate. Colonies were counted and expressed logarithmically (log10 CFUg–1). Mean and standard deviation (SD) were calculated using Microsoft Office Excel 2003 software (Microsoft Corporation, Redmont, USA). The toxin values obtained for samples were acquired and analyzed using SPSS version 15 and averages results are expressed with standard deviation mean (SD). The t-test was used to compare the differences in recoveries and detection limits. 3. Results and Discussion 3.1. Mycological Profile of Infant Food Products A total of 84 baby food samples were tested for the presence of fungi and metabolites produced by these isolates. Table 1 shows the fungal counts in the infant products as received and after storage of samples at 25?C and 80% relative humidity for 7 days. For products which were positive for presence of fungi, the count was between 1.1 and 4.7 log10CFUg–1. Two samples (2.4%) showed the highest fungal counts of ≥4.0 log10CFUg–1. Fungi were not detected in 50 of the samples (17.9%) on any of the 2 media even after incubation of products at 25?C and 80% humidity The genera Aspergillus spp., Penicillum spp. and Mucor were isolated from the samples but no further morphological studies were conducted to classify the isolates to species level. The twenty four isolated strains consisted of five Aspergillus spp., thirteen Peniciillum spp., five Mucor and one unknown. There was a slight increase in the count of fungi in most of samples after 7 days incubation at 25?C and 80% relative humidity, although one sample showed an increase in the count from 3.43 log10CFUg–1 to 4.48 log10CFUg–1. 3.2. Occurrence of Mycotoxigenic Fungi and Mycotoxins in Infant Food Products. The mycotoxins produced by the isolated strains on two mycological media are shown in Table 2. Both media showed similar results. The TLC analysis indicated that Copyright © 2011 SciRes. 753 all stains of Aspergillus spp isolates were able to produce aflatoxins, seven out of thirteen strains of Penicillium spp were mycotoxin positive and most strains were able to produce citrinin; five strains produced unidentified fluorescent bands, which are thought to be either unidentified mycotoxins or pigments produced by fungi. The results also indicated that there was a slight increase ≤ 1.0 log10CFUg–1 in the total number of fungi in some samples after storage of the samples at 80% relative humidity (Table 1). The percentage recoveries of AFs in the products spiked with 10 ng of AFs·g–1 were 98% for AFB1, 95% for AFB2, 90% for AFG1 and 94% for AFG2. In this study, aflatoxins were not quantifiable in the majority of samples (97.6%), while 2.4% of the samples were found to contain the toxins. The amounts of aflatoxins (AFs) of the two samples were 19 and 70 µg·kg–1 as shown in Figures 1(c) and (d). In view of the high recovery of aflatoxins from artificially contaminated samples this indicates that these samples indeed contained significant levels of aflatoxin (Table 3). These amounts were higher than the maximum tolerance limit accepted by European Union as guideline levels for cereal-based feeds (5 µg·kg–1 for AFB1 and 10 µg·kg–1 for total aflatoxin in cereal based feeds) [19]. However, common aflatoxin producing fungi such as A. flavus and A. parasticus were not isolated from positive samples. The production of mycotoxins does not correlate directly with the growth of the fungi and it is possible that the mycotoxins may have been within the raw materials before processing. Since mycotoxin limits have not been established in Libya, limits for the EC Regulations were used as a guide for this study. Many studies on the presence and quantity of mycotoxins in food and feed products have been conducted worldwide [23-25] but only a few studies for the presence of mycotoxins in baby food [7,26,27]. This is in spite of the fact that cereals and dried fruits are used as ingredient in infant food in combination with milk. In a Korean study, 85% infant formulae samples were found to be contaminated with AFM1 with a mean concentration of 46 ng·kg–1 [28]. Araguas et al. [29] examined twenty samples of cereals-based baby foods in Spain (Navarra) for OTA contamination. Ochratoxin A was detected in fourteen of the samples (limit of detection 0.035 µg·kg–1). In another survey Razzazi-Fazeli et al. [30] examined twelve baby foods and found no aflatoxins in the products. Sewram et al. [31] investigated corn-based infant food from markets in Brazil. They found that AFB1 was present in seven of eight samples ranging from 30 to 6127 µg·kg–1 and two of eight samples were positive for AFB2 ranging from 53 to 1738 µg·kg–1. A study of mycotoxins in infant foods including cereal-based infant foods—soy, wheat, oat, FNS 754 Occurrence of Fungi and Mycotoxins in Some Commercial Baby Foods in North Africa Table 1. Total count of fungi before and after storage of samples at 25?C and 80% relative humidity (RH) for 7 days. Sample Number 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 Main ingredients Rice flour, maltodextrin. Rice flour, malt maltodextrin. Wheat flour, sugar, vegetable. Wheat flour, vegetable. Rice flour with nuts Rice flour, maltodextrin. Rice flour, maltodextrin. Cereal with milk Rice flour with milk Rice flour with milk Rice flour, malt maltodextrin. Rice flour, malt maltodextrin. Wheat flour, banana, skimmed milk powder, whole milk powder, malt extract, milk fat. Wheat flour, vegetables (carrot, tomato, peas, spinach), skimmed milk powder, malt extract, milk fat. Wheat flour, corn starch. Milk, cereal, orange and honey, skimmed milk, wheat flour. Rice flour. Wheat flour, vegetable. Wheat flour, corn starch. Rice flour with nuts Wheat flour, corn starch. Rice flour Wheat flour, corn starch. Milk, cereal, orange and honey, skimmed milk, wheat flour. Milk, cereal, orange and honey, skimmed milk, wheat flour. Wheat flour, skimmed milk powder, banana, malt extract, milk fat. Wheat flour, banana, skimmed milk powder, whole milk powder, malt extract, milk fat. Rice flour. Wheat flour, vegetables (carrot, tomato, peas, spinach), skimmed milk powder, malt extract, milk fat. Cereal with milk Ground nuts and mixed grains. Ground nuts and mixed grains. Ground nuts and mixed grains. Ground nuts and mixed grains. Rice flour with milk Milk, cereal, orange and honey, skimmed milk, wheat flour. Milk, cereal, orange and honey, skimmed milk, wheat flour. Milk, cereal, orange and honey, skimmed milk, wheat flour. Skimmed milk, wheat flour, fruit concentrates (orange,banana, lemon). Skimmed milk, wheat flour, fruit concentrates (orange,banana, lemon). Wheat flour, corn starch. Rice flour Wheat flour, vegetable. Wheat flour, corn starch. Ground nuts and mixed grains. Ground nuts and mixed grains. Ground nuts and mixed grains. Wheat flour, vegetable. Ground nuts and mixed grains. Wheat flour, banana, skimmed milk powder, whole milk Copyright © 2011 SciRes. Storage at room Temp (21?C ± 1?C) Total count of fungi log10CFUg–1 ND 2.6 ± 0.0 3.0 ± 0.1 2.9 ± 0.0 2.8 ± 0.1 3.2 ± 0.1 2.3 ± 0.0 2.1 ± 0.0 2.5 ± 0.1 ND ND ND Storage at 25?C with 80% RH Total count of fungi log10CFUg–1 ND 2.8 ± 0.0 3.5 ± 0.2 2.9 ± 0.1 2.7 ± 0.0 3.9 ± 0.2 2.7 ± 0.0 2.9 ± 0.1 2.7 ± 0.0 ND 1.1 ± 0.0 ND 2.8 ± 0.1 2.8 ± 0.1 2.4 ± 0.0 2.6 ± 0.1 2.5± 0.0 2.8 ± 0.0 2.8 ± 0.0 2.7 ± 0.1 2.5 ± 0.0 2.4 ± 0.2 1.5 ± 0.0 2.4 ± 0.1 2.8 ± 0.1 ND 2.6 ± 0.1 2.9 ± 0.1 2.6 ± 0.0 2.4 ± 0.1 2.9 ± 0.1 3.3 ± 0.2 ND 2.7 ± 0.1 3.1 ± 0.2 2.4 ± 0.1 1.2 ± 0.1 3.8 ± 0.2 3.0 ± 0.1 3.9 ± 0.1 ND 1.3 ± 0.1 2.9 ± 0.0 3.4 ± 0.2 2.8 ± 0.0 3.0 ± 0.1 3.2 ± 0.2 ND 3.3 ± 0.4 3.5 ± 0.1 1.9 ± 0.0 1.5 ± 0.0 3.7 ± 0.3 ND 3.7 ± 0.1 3.9 ± 0.1 3.9 ± 0.1 1.6 ± 0.1 2.8 ± 0.1 2.6 ± 0.1 2.8 ± 0.1 2.7 ± 0.2 3.3 ± 0.1 3.6 ± 0.4 ND 1.3 ± 0.0 ND ND ND 3.6 ± 0.1 ND 2.9 ± 0.1 4.4 ± 0.2 3.4 ± 0.2 1.8 ± 0.0 3.4 ± 0.1 3.5 ± 0.2 3.4 ± 0.0 ND 3.8 ± 0.2 ND 2.8 ± 0.1 4.9 ± 0.1 3.5 ± 0.2 1.7 ± 0.1 3.1 ± 0.1 3.9 ± 0.2 3.4 ± 0.2 FNS 755 Occurrence of Fungi and Mycotoxins in Some Commercial Baby Foods in North Africa 51 52 53 54 powder, malt extract, milk fat Rice flour, maltodextrin. Wheat flour, vegetables (carrot, tomato, peas, spinach), skimmed milk powder, malt extract, milk fat.. Cereal with milk Ground nuts and mixed grains. 3.7 ± 0.1 3.7 ± 0.1 3.4 ± 0.1 3.6 ± 0.1 3.3 ± 0.1 3.43 ± 0.17 3.3 ± 0.0 4.5 ± 0.1 Values are mean (n = 3) ± standard deviation; ND = not detected