Effect of Saccharomyces cerevisiae yeast on ruminal detoxification of aflatoxin B[1]

Background: Yeasts are microorganisms that have the ability to absorb aflatoxins

Objectives: The effect of the yeast Saccharomyces cerevisiae [PTCC 5177] on aflatoxin B] detoxification and absorption of toxin in in vitro [the cow rumen] was investigated

Methods: For this purpose, the yeast used in various treatments [live-treated, autoclave, heat-treated, treated with acid 100 °C] was prepared and added to the rumen of cattle. Af-latoxin E in different doses [0, 5, 10,20] ppb in the rumen were added and were incubated at 37°C for one and two hours. The amount of toxin residues was measured by ELISA using Europroxima kits. RESULTS: The results showed that microorganisms that have been treated in an autoclave have the highest amount of toxin removal [90.5%] [p<0.05]. Also, with increases in the incubation time, the amount of toxin absorbed significantly increased [78%] [p<0.05] and with increasing concentrations of toxin in vitro the yeast's ability to absorb toxin increases. These results demonstrate that the major toxin is absorbed by the yeast cell wall and therefore non-living microorganisms shown an ability to absorb higher. This is because the composition of the yeast cell wall mannoprotein that are effective at absorb in toxin

Conclusions: As a strategy for the animal feed industry the use of glycomannan yeast cell wall can be useful for reducing aflatoxin B

In vitro antimicrobial activity of the essential oil of Ziziphora clinopodioides L. on food spoilage and pathogenic bacteria

The genus Ziziphora clinopodioides Lam. [Lamiaceae] are grown in most part of Iran. This plant has been used as an additive in yoghurt and other dairy products, but there is little study about antimicrobial activity of Ziziphora clinopodioides on food spoilage and pathogenic bacteria. The main goal of this study was to evaluate the antimicrobial activity of the essential oil of Ziziphora clinopodioides against some food spoilage and pathogenic bacteria and determine Minimum inhibitory concentration [MIC] and minimum bactericidal concentration [MBC]. Essential oil of Ziziphora [Ziziphora clinopodioides L.] was tested for it s growth inhibitory and bactericidal effect on 6 Gram-negetive [Enterobacter aerogenes, Escherichia coil, Klebsiella pneumoniae, Salmonella enteritidis, Pseudomonas aeroginosa and Shigella dysenteria] and 3 Gram-positive species [Listeria monocytogenes, Staphylococcus aureus and Bacillus cereus]. Minimum inhibitory concentration [MIC] was determined using dilution method and minimum bactericidal concentration [MBC] was taken from the concentration of the lowest dosed test tube showing no growth on subcultured. All test organism were inhibited by Ziziphora clinopodioides L. except Pseudomonas aeroginosa and Shigella dysenteria. The MIC and MBC for Gram-negetive bacteria, including Enterobacter aerogenes, Escherichia coil, Klebsiella pneumoniae and Salmonella enteritidis were 250, 500,125 and 250 /tg/ml respctivily. The MIC for Gram-negetive bacteria, including Listeria monocytogenes, Staphylococcus aureus and Bacillus cereus were 125, 1000, 125 /g/ml respctivily. It is concluded that essential oil of ziziphora has antimicrobial activity on food spoilage and pathogenic bacteria. According to the results of this study, It is applicable to use essential oil of Ziziphora as the natural preservatives and flavoring agents in food products