https://ucanr.edu/datastoreFiles/608-176.pdf

Fresh-cut product sanitation and wash water disinfection: Problems and solutions

Application of ultraviolet light-emitting diodes (UV-LEDs) for water disinfection: A review

Nonthermal plasma (NTP) is electrically energized matter and is composed of highly reactive species including gas molecules, charged particles in the form of positive ions, negative ions, free radicals, electrons and quanta of electromagnetic radiation (photons) at near-room temperature. NTP technology is an emerging nonthermal technology with potential applications for sterilization in the food industries. An upsurge in the research activities for plasma-based inactivation of food-borne pathogens is evident in recent years. These studies have shown that NTP can be used for the surface decontamination of raw produce including; dried nuts and packaging materials. This paper reviews the action of plasma agents on the microbial classes and describes proven and potential applications in food processing. Novel developments in the technology and a future outlook for the application to foods are discussed.

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Nonthermal Plasma Inactivation of Food-Borne Pathogens

Cold plasma is a novel nonthermal food processing technology that uses energetic, reactive gases to inactivate contaminating microbes on meats, poultry, fruits, and vegetables. This flexible sanitizing method uses electricity and a carrier gas, such as air, oxygen, nitrogen, or helium; antimicrobial chemical agents are not required. The primary modes of action are due to UV light and reactive chemical products of the cold plasma ionization process. A wide array of cold plasma systems that operate at atmospheric pressures or in low pressure treatment chambers are under development. Reductions of greater than 5 logs can be obtained for pathogens such as Salmonella, Escherichia coli O157:H7, Listeria monocytogenes, and Staphylococcus aureus. Effective treatment times can range from 120 s to as little as 3 s, depending on the food treated and the processing conditions. Key limitations for cold plasma are the relatively early state of technology development, the variety and complexity of the necessary equipment, and the largely unexplored impacts of cold plasma treatment on the sensory and nutritional qualities of treated foods. Also, the antimicrobial modes of action for various cold plasma systems vary depending on the type of cold plasma generated. Optimization and scale up to commercial treatment levels require a more complete understanding of these chemical processes. Nevertheless, this area of technology shows promise and is the subject of active research to enhance efficacy.

Cold plasma decontamination of foods.

Exploitation of vegetables and fruits through lactic acid fermentation

Pulsed light (PL) is a technique to decontaminate surfaces by killing microorganisms using pulses of an intense broad spectrum, rich in UV-C light. The present review is focused on the application of PL for food decontamination. It revises the mechanism of microbial inactivation (UV-C as the most important part of the spectrum, photothermal and photochemical mechanisms, inactivation curve, peak power dependence, and photoreactivation), the factors affecting its efficacy, the advantages and problems associated with PL treatment, and results obtained in vitro. Examples of applications to foods are given, including microbial inactivation, and effects on food matrices.

Pulsed light for food decontamination: a review

Minimally processed fruits and vegetables (MPFV) have a short shelf-life due to their metabolism and the action of spoilage microorganisms. Chlorine dioxide is a powerful oxidizing agent that can be used as decontaminant. It does not form significant amounts of chlorinated by-products like as do chlorine. This article revises the characteristics of chlorine dioxide, the basis of its antimicrobial action, and its effect on microorganisms and on the sensory quality and shelf-life of fresh produce and mainly MPFV. Moreover, it discusses its effects on the physiology and nutritional quality of MPFV, and provides information on its toxicity and legal status.

Chlorine dioxide for minimally processed produce preservation : a review

Intense light pulses decontamination of minimally processed vegetables and their shelf-life.

V.M. GOMEZ-LOPEZ, F. DEVLIEGHERE, V. BONDUELLE AND J. DEBEVERE. 2005. Aim: To determine the influence of several factors on the inactivation of micro-organisms by intense light pulses (ILP). Methods and Results: Micro-organisms on agar media were flashed 50 times under different conditions and their inactivation measured. Micro-organisms differed in sensitivity to ILP but no pattern was observed among different groups. Several enumeration methods to quantify the effect of ILP were investigated and showed relevant differences, shading effect and photoreactivation accounted for them, the strike method yielded the most reliable results. Higher decontamination efficiencies were obtained for Petri dishes located close to the strobe and inside the illumination cone. Decontamination efficacy decreased significantly at contamination levels >6AE85 log10. After 13 successive treatments, no resistance to ILP could be demonstrated. Media warming up depended on the distance from the strobe and the number of flashes. Conclusions: For an industrial implementation: the position and orientation of strobes in an unit will determine the lethality, products should be flashed as soon as possible after contamination occurs, a cooling system should be used for heat-sensitive products and flashed products should be light protected. No resistant flora is expected to develop. Significance and Impact of the Study: Conclusions derived from this work will allow a better implementation of this decontamination technique at industrial level.

Factors affecting the inactivation of micro‐organisms by intense light pulses

Ultrasonic treatments were applied at a frequency of 20 kHz and three wave amplitudes for 2, 4, 6, 8 and 10 min, to orange juice with added calcium. Aerobic mesophilic count (AMC), yeast and mold counts (YMC), Hunter color values, ascorbic acid concentration and sensory attributes were measured. Wave amplitude of 89.25 μm for 8 min was selected for final treatment of the juice, and storage studies were performed at 4 and 10 °C. Microbial inactivation followed Geeraerd, Herremans, and Van Impe (2000) model. The treatment decreased AMC by 1.38 log CFU/ml, and YMC by 0.56 log CFU/ml. The sensory quality of the juice was slightly deteriorated after treatment, but during storage, it degraded faster for controls than for treated samples. Controls were rejected by the sensory panel after 6 days storage at 4 °C due to off-flavor, and ultrasonicated juice after 10 days due to off-odor. Consequently, a shelf-life extension of 4 days was achieved. At both times (6 or 10 days) AMC reached 6.5 log CFU/ml, which suggests a relation between sensory deterioration and bacterial activity. Sonication also affected color and decreased ascorbic acid content. This study shows that ultrasonication may be useful to extend the shelf-life of orange juice.

Vicente M. Gómez-López

Papers

Pulsed light for food decontamination: a review

Chlorine dioxide for minimally processed produce preservation : a review

Intense light pulses decontamination of minimally processed vegetables and their shelf-life.

Factors affecting the inactivation of micro‐organisms by intense light pulses

Microbiological and sensory quality of sonicated calcium-added orange juice