Effect of naturally occurring antimicrobials and chemical preservatives on the growth of Aspergillus Parasiticus

Abstract

Effect of water activity (aw, 0.99), pH (4.5) and their interaction on the growth inhibition of Aspergillus parasiticus was studied on potato dextrose agar (PDA) using various antimicrobial agents (citral, carvacrol, eugenol, cineole, thymol guaiacol, vanillin, anethol, potassium sorbate and sorbic acid). The results demonstrate that colony diameter (mm) exhibited a constant increase with time (zero order kinetics) for all antimicrobials evaluated. Eugenol and sorbic acid inhibited the test fungi at 300 and 600 ppm, respectively. Radial growth rate (RGR) of A. parasiticus was significantly (p < 0.05) different among different antimicrobials as well as the concentrations tested. However, this difference was not observed with higher concentration of citral, eugenol, vanillin and sorbic acid. Among the antimicrobials evaluated potassium sorbate, cineole, anethol and guaiacol were least effective. Thymol, eugenol and carvacrol were more effective in inhibiting A. parasiticus even with low concentration (150 ppm) as their mean RGR was zero even after 20 days of incubation (pH 4.5).

Evaluation of Pyrolysis Oil as Carbon Source for Fungal Fermentation

“…Its toxicity is based on its membrane activity (Mörsen and Rehm, 1990). Similar effects of guaiacol on A. parasiticus have been published (Pillai and Ramaswamy, 2012). At the lowest tested concentration of phenol, cresols, and guaiacol, more malic acid was detected than in the control approach, indicating either a promoting effect of phenol on malic acid production or a better release of the organic acids from the cell.…”

Banana by-products: an under-utilized renewable food biomass with great potential

“…Current trends of industry show increase awareness towards the drawbacks of synthetic chemical preservatives and opt for minimally processed food or employing natural techniques in food preservation (Tiwari et al 2009). Natural antimicrobials from numerous plant sources including spices and herbs have been well documented in suppressing food spoilage microbes and foodborne pathogens (Kumar and Tanwar 2011;Kumudavally et al 2011;Pillay and Ramaswamy 2012;Padam et al 2012a) further strengthens the concept of natural ingredients for food preservation. Antibacterial compounds such as ß-sitosterol, 12-hydroxystrearic acid and malic acid isolated from banana peels (Musa paradisiaca) shown to be a good suppressor of foodborne pathogens including Staphylococcus aureus, Bacillus cereus, Salmonella enteritidis and Escherichia coli (Mokbel and Hashinaga 2005) and could potentially be applied into food systems in the future.…”

Microwave-assisted hydrodistillation of essential oil from rosemary

“…Spices, herbs and their essential oils have varying degree of biological activity. There has been growing interest in the use of naturally occurring substances as antioxidants and antimicrobials in recent years (Pillai and Ramaswamy 2011). R. officinalis L. has been shown to exhibit antimicrobial and antioxidant activities (Baratta et al 1998;Pintore et al 2002;Angioni et al 2004;Saccheti et al 2005;Okoh et al 2010;Karpiǹska-Tymoszezyk 2011).…”