Creating novel approaches to mitigate aflatoxin risk in food and feed with lactic acid bacteria - mold growth inhibition and aflatoxin binding

Aflatoxins, produced by Aspergillus fungi, are ubiquitous toxins and they can present a severe health risk to humans and animals if contaminated food and feed is consumed. Fungi live in the soil and on the surface of the crop and Aspergillus species are dominant in favorable conditions of maize cultivation areas. Climate change could threaten the production of safe food by promoting Aspergillus growth and aflatoxin production in food and feed. A novel biological approach using lactic acid bacteria (LAB) could reduce the health risks of aflatoxins through inhibiting mold growth, thus aflatoxin production and by binding existing aflatoxins. LAB are commonly used in fermented food production; they are also known to inhibit mold growth and interact with aflatoxins. LAB provide a potential novel approach to mitigate the mould growth and aflatoxin production in maize during storage and after food consumption. Mold growth inhibition by certain LAB strains may be caused by competition for resources between bacterial cells and fungi and/or production of antifungal compounds such as organic acids. Aflatoxin binding is more complex. Binding is a reversible reaction, which occurs on bacterial surfaces and involves interaction with carbohydrates, peptidoglycan and to some extent protein structures. Aflatoxin binding seems to be highly related to strain, matrix, temperature, pH, incubation time and related conditions. There are two different aspects of aflatoxin risk mitigation in this research. First is the fungal growth inhibition with LAB and second is aflatoxin binding from food and feed with LAB. We have isolated 200 strains of bacteria from 21 different indigenous fermented dairy and cereal products prepared locally in different parts of Kenya. Firstly, these strains are being tested for their growth inhibition abilities against aflatoxin producing Aspergillus fungi in laboratory conditions. Secondly, the same strains are tested for their abilities to bind and retain aflatoxin M1 and B1. Later, these same effective strains will be tested in various food and feed matrices against Aspergillus growth and then the ones with most potential will be identified. This approach aims at providing a safe method of reducing aflatoxin absorption in human gastrointestinal tract after ingesting fermented maize or dairy products, which are contaminated with aflatoxins. Novel biological methods can have a role in preventing toxic effects of aflatoxins in food and feed. Exploitation of LAB is a good option for existing methods as LAB are generally recognized as safe. This research is done as part of FoodAfrica programme, which is a research, and development programme and the main funding agency being Finnish Ministry for Foreign Affairs. The research is partnering with MTT Agrifood Research Finland and ILRI International Livestock Research Institute

Multi-ethnic genome-wide association study for atrial fibrillation

Atrial fibrillation (AF) affects more than 33 million individuals worldwide and has a complex heritability. We conducted the largest meta-analysis of genome-wide association studies (GWAS) for AF to date, consisting of more than half a million individuals, including 65,446 with AF. In total, we identified 97 loci significantly associated with AF, including 67 that were novel in a combined-ancestry analysis, and 3 that were novel in a European-specific analysis. We sought to identify AF-associated genes at the GWAS loci by performing RNA-sequencing and expression quantitative trait locus analyses in 101 left atrial samples, the most relevant tissue for AF. We also performed transcriptome-wide analyses that identified 57 AF-associated genes, 42 of which overlap with GWAS loci. The identified loci implicate genes enriched within cardiac developmental, electrophysiological, contractile and structural pathways. These results extend our understanding of the biological pathways underlying AF and may facilitate the development of therapeutics for AF

Creating novel approaches to mitigate aflatoxin risk in food and feed with lactic acid bacteria: Fungal growth inhibition

Aflatoxins, produced by Aspergillus fungi, are ubiquitous toxins and they can present a severe health risk to humans and animals if contaminated food and feed is consumed. Fungi live in the soil and on the surface of the crop and Aspergillus species are dominant in favorable conditions of maize cultivation areas. A novel biological method could reduce the health risks of aflatoxins through inhibiting mold growth and thus aflatoxin production. Lactic acid bacteria (LAB) are commonly used in fermented food production; they are also known to inhibit mold growth. Mold growth inhibition by certain LAB strains may be caused by competition for living conditions between bacterial cells and fungi and/or production of antifungal compounds such as organic acids. 200 LAB strains of bacteria have been isolated from 21 different indigenous fermented dairy and cereal products prepared locally in different parts of Kenya. These strains are being tested for their growth inhibition abilities against aflatoxin producing Aspergillus fungi in laboratory conditions. Later, these same effective strains will be tested in various food and feed matrices against Aspergillus growth and then the ones with most potential will be identified. Novel biological methods can have a role in preventing toxic effects of aflatoxins in food and feed. Exploitation of LAB is a good option for existing methods as LAB are generally recognized as safe

Potential of lactic acid bacteria in aflatoxin risk mitigation

Aflatoxins (AF) are ubiquitous mycotoxins contaminating food and feed. Consumption of contaminated food and feed can cause a severe health risk to humans and animals. A novel biological method could reduce the health risks of aflatoxins through inhibiting mold growth and binding aflatoxins. Lactic acid bacteria (LAB) are commonly used in fermented food production. LAB are known to inhibit mold growth and, to some extent, to bind aflatoxins in different matrices. Reduced mold growth and aflatoxin production may be caused by competition for nutrients between bacterial cells and fungi. Most likely, binding of aflatoxins depends on environmental conditions and is strain-specific. Killed bacteria cells possess consistently better binding abilities for aflatoxin B-1 (AFB(1)) than viable cells. Lactobacilli especially are relatively well studied and provide noticeable possibilities in binding of aflatoxin B-1 and M-1 in food. It seems that binding is reversible and that bound aflatoxins are released later on (Haskard et al., 2001; Peltonen et al., 2001). This literature review suggests that novel biological methods, such as lactic add bacteria, show potential in mitigating toxic effects of aflatoxins in food and feed.201

Analysis of antibiotic residues in milk from smallholder farms in Kenya

The aim of this study was to determine the occurrence of antibiotic residues in Kenyan smallholder farm milk using screening tests, and to identify the antibiotic residue group. A total of 480 milk samples were analyzed. All samples were analyzed with the Delvotest® screening test. A Hundred and fourteen (24%) samples were positive, 71 (15%) unclear and 295 (61%) negative. Sixty-two samples were further tested with the group specific Trisensor test. Twenty four percent (15/62) were positive. This indicated that by estimation, 9% of all the 480 samples have been positive with the Trisensor test and 5% would have contained beta-lactams, 2.5 % sulfonamides and 0.6 % tetracyclines. Samples with a positive Trisensor test results were further analyzed with HPLC but no antibiotics could be identified. Seventy six percent of the Delvotest® positive samples were negative in Trisensor test. Microbiological inhibitor methods are demanding for the sample conditions and were found not to be best suited to the conditions encountered in smallholder farms in Kenya. The results indicate that antibiotic residues are found in milk produced on small scale farms in Kenya and suggest that training is needed on the use of veterinary drugs

Aspergillus flavus growth inhibition by Lactobacillus strains isolated from traditional fermented Kenyan milk and maize products

Certain strains of lactic acid bacteria have been reported to inhibit fungal growth and may so be potential as biocontrol agents. In this study, 171 LAB strains were isolated from traditional fermented Kenyan milk and maize products and tested against aflatoxin-producing A. flavus fungi. The three LAB strains showing highest antifungal activity were identified as Lactobacillus plantarum. None of the strains were able to completely inhibit fungal growth under conditions favorable for fungi and suboptimal for LAB. These conditions probably reduced the growth and metabolic activity of some LAB isolates, as several growth-related aspects like production of antifungal biomolecules and other metabolites contribute to the inhibiting activity. The results suggest that certain LAB strains could be employed in food to control the growth of aflatoxigenic fungi. Further studies to establish the efficacy of the potential LAB strains in fermented products are in progress