Effects of hurdle technology on Monascus ruber growth in green table olives: a response surface methodology approach

ABSTRACT An ascomycetes fungus was isolated from brine storage of green olives of the Arauco cultivar imported from Argentina and identified as Monascus ruber. The combined effects of different concentrations of sodium chloride (3.5-5.5%), sodium benzoate (0-0.1%), potassium sorbate (0-0.05%) and temperature (30-40 °C) were investigated on the growth of M. ruber in the brine of stored table olives using a response surface methodology. A full 24 factorial design with three central points was first used in order to screen for the important factors (significant and marginally significant factors) and then a Face-Centered Central Composite Design was applied. Both preservatives prevented fungal spoilage, but potassium sorbate was the most efficient to control the fungi growth. The combined use of these preservatives did not show a synergistic effect. The results showed that the use of these salts may not be sufficient to prevent fungal spoilage and the greatest fungal growth was recorded at 30 °C.

Chemicals and lemon essential oil effect on Alicyclobacillus acidoterrestris viability

Alicyclobacillus acidoterrestris is considered to be one of the important target microorganisms in the quality control of acidic canned foods. There is an urgent need to develop a suitable method for inhibiting or controlling the germination and outgrowth of A.acidoterrestris in acidic drinks. The aim of this work was to evaluate the chemicals used in the lemon industry (sodium benzoate, potassium sorbate), and lemon essential oil as a natural compound, against a strain of A.acidoterrestris in MEB medium and in lemon juice concentrate. The results pointed out that sodium benzoate (500-1000-2000 ppm) and lemon essential oil (0.08- 0.12- 0.16%) completely inhibited the germination of A. acidoterrestris spores in MEB medium and LJC for 11 days. Potassium sorbate (600-1200 ppm) was more effective to inhibit the growth of the microbial target in lemon juice than in MEB medium. The effect of sodium benzoate, potassium sorbate and essential oil was sporostatic in MEB and LJC as they did not affect spore viability.

In vitro activity of sodium-benzoate against isolates of methicillin-resistant Staphylococcus aureus / Actividad In Vitro del Benzoato de Sodio contra los Aislados de Staphylococcus aureus Resistentes a la Meticilina

BACKGROUND: Worldwide, methicillin-resistant Staphylococcus aureus (MRSA) rates have increased dramatically during the last decades. Sodium benzoate (SB) is a chemical substance that is used for preparing food and drinks and in the treatment of some metabolic (urea cycle disorders and hepatic coma) diseases. No studies were found which focussed on the effects of SB in MRSA infections. The aim was to determine in vitro activity of sodium benzoate against MRSA clinical isolates. METHODS: In this study, MIC for SB in 36 MRSA and 29 methicillin-sensitive Staphylococcus aureus (MSSA) isolates were determined by a broth microdilution method recommended by the National Committee for Clinical Laboratory Standards. RESULTS: The MIC at which all of the MRSA and MSSA strains were inhibited was at 32 microg/ml and higher concentrations. CONCLUSION: Sodium benzoate showed good in vitro activity against clinically relevant MRSA and MSSA isolates. It is suggested in this study that this cheap substance, which has been used for systemic and local treatment of infection in humans, may be used alternatively for the treatment of MRSA infections. However, it is clear that more comprehensive and in vivo studies are needed to further elucidate the activity of SB against MRSA infections

Antecedentes: A nivel mundial, los índices de Staphylococcus aureus resistente a la meticilina (SARM) han aumentado dramáticamente durante las últimas décadas. El benzoato de sodio (BS) es una sustancia química que se usa ampliamente en la preparación de comidas y bebidas, y en el tratamiento de algunas enfermedades metabólicas (trastornos del ciclo de la urea y coma hepático). No encontramos ningún estudio dedicado específicamente a los efectos del BS en las infecciones por SARM. Nos trazamos como objetivo determinar la actividad in vitro del benzoato de sodio contra los aislados clínicos de SARM. Métodos: En este estudio, se determinaron la concentración mínima inhibitoria (CMI) para el BS en 36 SARM y 29 aislados de Staphylococcus aureus sensible a la meticilina (SASM), mediante un método de microdilución en caldo, recomendado por el Comité Nacional para las Normas de Laboratorios Clínicos. Resultados: La CMI a la que se inhibieron todas las cepas de SARM y SASM fue de 32 µg/ml y concentraciones más altas. Conclusión: El benzoato de sodio demostró ser bueno en la actividad in vitro contra los aislados de SARM y SASM clínicamente relevantes. Sugerimos que esta sustancia económica, que se ha usado para el tratamiento sistémico y local de infecciones en los seres humanos, puede usarse alternativamente para el tratamiento de infecciones por SARM. Sin embargo, está claro que se requieren estudios in vivo y más exhaustivos, que contribuyan a un entendimiento aún más claro de la actividad del BS contra las infecciones por SARM.

Evaluation of crude sesquiterpenoid extract of Phellinus fastuosus as a natural preservative.

It has been revealed that the use of synthetic food preservatives has variety of various side effects and hence search of safe and effective natural preservative has become a need. With the afore said objective the present study to screen the possibility of using sesquiterpenoid extract of local folk mushroom Phellinus fastuosus as food preservative was undertaken. Microbial growth inhibition by sesquiterpenoid extract of Phellinus was evaluated in the media with natural ingredient such as milk agar (MA), tomato juice agar (TJA), wheat flour agar (WFA) and pineapple juice agar (PAJA) with the composition with Phellinus extract, sodium benzoate and combinations. Three strains of bacteria and one strain of fungus were used astest organisms. The sesquiterpenoid extract of Phellinus at 0.02% concentration significantly inhibited the growth of all test organisms on natural media and the results were comparable with sodium benzoate. Similarly combination of Phellinus extract and sodium benzoate completely inhibited the growth of all microorganisms in all media, suggesting the possibility of using the Phellinus extract as food preservative.