Fulya Turantaş

Decontamination efficiency of high power ultrasound in the fruit and vegetable industry, a review☆

Decontamination of fresh fruits and vegetables is an important unsolved technological problem. The main focus of this review is to summarize and synthesize the results of studies and articles about ultrasonic processing which can be adapted to the wash water decontamination process for fruits and vegetables. This review will also provide an overview about the importance of an effective wash water decontamination process in fruits and vegetables, the increase of foodborne outbreaks caused by fresh fruits and vegetables, microbial inactivation using ultrasound, and an interpretation of the high power ultrasound results in the fruits and vegetable industry. In addition, the limitations of ultrasonic processing in commercial applications have also been introduced.

Effect of potassium sorbate and sodium benzoate on microbial population and fermentation of black olives

Black olive fermentation characteristics and diffusion of preservatives into olives were evaluated in brines containing 500 ppm potassium sorbate, 1000 ppm sodium benzoate, 500 ppm sodium benzoate + 250 ppm potassium sorbate and no preservative (control). Changes in brine pH, acidity and microbial population (lactic acid bacteria, yeasts, moulds) were followed during fermentation and storage. Results indicated that K-sorbate when used at 500 ppm concentration in black olive fermentation had a slight stimulatory effect on the growth of lactic acid bacteria. The yeast counts of brines containing 500 ppm K-sorbate and 1000 ppm Na-benzoate were lower than for the brine containing 250 ppm K-sorbate + 500 ppm Na-benzoate and for the control with no preservative, while mould growth was completely inhibited in all treatments during fermentation. Mould counts stayed below the detection limit (<10 cfu g−1) during 214 days of vacuum-packaged storage. Yeast counts showed a progressive decline within 28 days of storage and then stayed relatively constant in all treatments thereafter. The level of yeast population was higher in the control sample than in the sample containing both preservatives during storage. The diffusion of Na-benzoate and K-sorbate into the olives after equilibrium was 64% and 80% during fermentation respectively. © 1999 Society of Chemical Industry