Perspectives for chitosan based antimicrobial films in food applications

Climate change associated effects on grape and wine quality and production

Plant extracts for the control of bacterial growth: efficacy, stability and safety issues for food application.

Fresh produce is more susceptible to disease organisms because of increase in the respiration rate after harvesting. The respiration of fresh fruits and vegetables can be reduced by many preservation techniques. Modified atmosphere packaging (MAP) technology is largely used for minimally processed fruits and vegetables including fresh, “ready-to-use” vegetables. Extensive research has been done in this research area for many decades. Oxygen, CO 2 , and N 2 , are most often used in MAP. The recommended percentage of O 2 in a modified atmosphere for fruits and vegetables for both safety and quality falls between 1 and 5%. Although other gases such as nitrous and nitric oxides, sulphur dioxide, ethylene, chlorine, as well as ozone and propylene oxide have also been investigated, they have not been applied commercially due to safety, regulatory, and cost considerations. Successful control of both product respiration and ethylene production and perception by MAP can result in a fruit or vegetable product of high organoleptic quality; however, control of these processes is dependent on temperature control.

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Modified atmosphere packaging of fresh produce: Current status and future needs

Summary
This paper proposes a review of some alternative approaches for food stabilisation and shelf life prolonging (based on the use of natural compounds and/or non-thermal techniques). After a brief description of food structure implication on the way of using the alternative approaches, two paragraphs summarise the topics of natural molecules (essential oils, lysozyme, lactoferrin and lactoperoxidase system, fatty acids, chitosan) and non-thermal approaches (high hydrostatic and homogenisation pressures, pulsed electric fields, high power ultrasound and irradiation). Finally, the last sections deal with the use of combined hurdles (along with the proposal of three possible modes of action of a multi-target preservation), the mathematical approaches for shelf life evaluating and some critical issues to be addressed in the future for a real scaling up of the proposed techniques.

Prolonging microbial shelf life of foods through the use of natural compounds and non-thermal approaches – a review

Effect of temperature on shelf life and microbial population of lightly processed cactus pear fruit

Summary
In enology, alcoholic fermentation is a complex process involving several mechanisms. Slow and incomplete alcoholic fermentation is a chronic problem for the wine industry and factors leading to sluggish and stuck fermentations have been extensively studied and reviewed. The most studied cause of sluggish and stuck fermentation is the nitrogen content limitation. Nevertheless, other factors, such as temperature of fermentation and sugar concentration can affect the growth of yeasts. In this study we modelled the yeast growth-cycle in wine model system as a function of temperature, sugar and ammonium concentrations; the individual effects and the interaction of these factors were analysed by means of a quadratic response surface methodology. Cell concentrations and weight loss were monitored in the whole wine fermentation process. The results of central composite design show that lower is the availability of nitrogen, higher is the cell growth rate; moreover, initial nitrogen concentration also influences survival time of Saccharomyces cerevisiae.

Effects of temperature, ammonium and glucose concentrations on yeast growth in a model wine system

Summary A study on the microflora of table olives »Bella di Cerignola«, produced according to Spanish style and natural processing, is presented. The samples (olives and brines) were taken at different fermentation phases; olives, before treatments, were analyzed too. pH was monitored and microbial populations were assessed by standard plate count. Determination of the following microbial groups was carried out: mesophilic bacteria, lactic acid bacteria, Enterobacteriaceae, Pseudomonadaceae, staphylococci, Micrococcaceae and yeasts. In the second phase, the identification of mesophilic bacteria, lactic acid bacteria and yeasts was performed. The amount of lactic acid bacteria and yeasts increased during the storage in all the samples, but no significant differences were observed between the two styles. At the end of fermentation an increase of Pseudomonadaceae cell load was observed, which was absent in the first phase of fermentation. The samples analyzed were extremely unsteady, therefore the addition of starter lactic acid bacteria could standardize olive processing. Lactobacillus plantarum, Bacillus spp. (mainly B. subtilis) and Candida spp. were the predominant species at the end of the processing.

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Daniela D’Amato

Papers

Prolonging microbial shelf life of foods through the use of natural compounds and non-thermal approaches – a review

Effect of temperature on shelf life and microbial population of lightly processed cactus pear fruit

Effects of temperature, ammonium and glucose concentrations on yeast growth in a model wine system

Microbial Characterization of Table Olives Processed According to Spanish and Natural Styles

Combined effects of temperature, water activity, and pH on Alicyclobacillus acidoterrestris spores.