Inhibition of growth and mycotoxin production of aspergllus and penicillium by some selected food additives [Eugenol, soeugenol and monolaurin]

Sabouraud dextrose agar was prepared to contain up to 300 ppm of eugenol, isoeugenol or monolaurin. Eight strains of mycotoxin and non-mycotoxin producing Aspergillus spp. and Penicillium spp. were tested in this study. Spore suspensions of the molds were spotted in the center of agar plates and the linear [radial] growth rate was monitored during incubation. All agents inhibited mold growth on agar surface, but isoeugenol and eugenol were more effective than monolaurin. The average decrease in linear growth rate in the presence of eugenol, isoeugenol and monolaurin was 62, 51 and 21% at 100 ppm and 84, 88 and 26% at 200 ppm, respectively. At 300 ppm of eugenol and isoeugenol, the surface growth of all fungi was inhibited completely. However, monolaurin up to 2000 ppm did not prevent the growth of the molds. Molds tested, except P. viridicatum NRRL 6062, did not vary significantly [at P = 0.05] in degree of inhibition by a particular antifungal agent. A. parasiticus was grown in modified yeast extract dextrose broth containing 100 ppm of the antifungal agents. Decreases in mycelial dry weight in the presence of eugenol, isoeugenol or monolaurin were 5.3, 7.9, 10.5%, respectively, and the corresponding reductions in aflatoxin B1 synthesized were 58, 57 and 25%. In conclusion, eugenol and isoeugenol have strong antifungal properties which are best manifested when the surface growth of molds on solid media is monitored

Enteric organisms prevalent in market fish with special reference to E coli

Fifty random samples of apparently fresh fish [20 from each of Carp and Tilapia nilotica besides ten samples from Clarias lazera] were collected from fish markets in Zagazig and were subjected to bacteriological examination for detection of enteric microorganisms. The obtained results revealed that Enterobacter aerogenes, and Proteus morganii were detected from various fish species, while neither salmonellae not shigellae could be obtained. The incidence of other enteric genera of microorganisms were recorded in different fish species. The serotyping of isolated E.coli showed that one isolate from Crap belonged to O[119]: K[59], while the other from Tilapia nilotica belonged to O[44]: K[74]. The public health importance of such existence was also discussed