INTRODUCTION. Food industry challenges

Transcription

1 COLD PLASMA

2 INTRODUCTION Food industry challenges Consumers expect that the food they consume is safe to eat. In addition, the consumer also wants the food to have high nutritional value with minimal preparation times, as evidenced by the growth in products such as convenience ready-to-eat (RTE) foods and minimally processed fresh produce. In order to meet these demands, food manufacturers are looking for new methods and technologies. A new technology which may meet manufacturers needs is cold plasma. History The word "PLASMA" was first applied to ionized gas by Dr. Irving Langmuir, an American chemist and physicist, in 1929.

3 WHAT IS PLASMA? Plasma is often called the "Fourth State of Matter," the other three being solid, liquid and gas. A plasma is a distinct state of matter containing a significant number of electrically charged particles, a number sufficient to affect its electrical properties and behavior. In an ordinary gas each atom contains an equal number of positive and negative charges; the positive charges in the nucleus are surrounded by an equal number of negatively charged electrons, and each atom is electrically "neutral." A gas becomes a plasma when the addition of heat or other energy causes a significant number of atoms to release some or all of their electrons. The remaining parts of those atoms are left with a positive charge, and the detached negative electrons are free to move about. Those atoms and the resulting electrically charged gas are said to be "ionized." When enough atoms are ionized to significantly affect the electrical characteristics of the gas, it is a plasma

4 METHODS OF GENERTIING PLASMA

5 GENARATION OF COLD PLASMA

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7 APPLICATION OF COLD PLASMA IN FOOD INDUSTRY Surface decontamination: Cold plasma can be used for decontamination of products where micro organisms are externally located. Unlike light (UV decontamination), plasma flows around objects, ensuring all parts of the product are treated. Mild surface decontamination For products like cut vegetables & fresh meat, there is no mild surface decontamination technology available currently; cold plasma could be used for this purpose..

8 A plasma torch can be applied to uncooked chicken in an effort to reduce its pathogen load. After treating the poultry for various times ranging up to 180 seconds, the plasma entirely or substantially reduced low levels of bacteria from both skinless chicken & chicken skin. Even bacteria levels on highly contaminated samples were significantly lowered.

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10 Cold plasma use in food packaging technology. Cold plasma technology is an emerging, green process offering man potential applications for food packaging. it was originally developed to increase the surface energy of polymers, enhancing adhesion,printability & sealability. it has recently emerged as a powerful tool for surface decontamination food packaging materials. Gas plasma reactions establish efficient inactivation of micro-organisms (bacterial cells, spores, yeasts and moulds) adhering to polymer surfaces within short treatment times. Packaging materials such as plastic bottles, lids and films can be rapidly sterilised using cold plasma, without adversely affecting their bulk properties or leaving any residues New trends aim to develop in package decontamination, offering non-thermal treatment of foods post packaging. (active packaging technique) it ia effective & quick method to destroy microbes.

11 Kevin Keener a professor of food science is developing methods using cold plasma to kill bacteria on in-package foods Kevin Keener, looks for new ways to kill harmful bacteria, such as E.coli and Salmonella, that contaminate foods and cause serious illnesses and deaths. His method uses electricity to generate a plasma, or ionized gas, from atmospheric gases inside the food package. This process creates a wide variety of bacteria-killing molecules including ozone, nitrogen oxides, hydrogen peroxide and others. These molecules only exist for a few hours and then revert back to the original atmospheric gas, leaving a bacteria-free product.

12 . Mode of action in decontamination food stuff/packaging material by cold plasma At the beginning.the vacuum ultraviolet (VUV) energy is very effective in the breaking most organic bonds (i.e., C-H,C-C, C=C, C-O, and C-N) of surface contaminants. This helps to break apart high molecular weight contaminants. A second cleaning action is carried out by the oxygen species created in the plasma (O2+, O2-, O3, O, O+, O-, ionised ozone, metastably-excited oxygen, and free electrons). These species react with organic contaminants to form H2O, CO, CO2, and lower molecular weight hydrocarbons. The resulting surface is ultraclean/sterilised. Thus, destruct the microbial cells by Disrupting bacteria cell membrane Denaturing proteins Damaging bacteria DNA

13 .Mode of action continue. pathogens such as Salmonella, Escherichia coli, Listeria monocytogenes, Staphylococcus aureus can be reduced by greater than 5 logs following treatment with cold plasma. Depending on the processing conditions, treatment times can range from 120 seconds to as little as 3 seconds Cold plasma, therefore, holds promise as a rapid, effective non thermal food processing technology

14 Nevertheless, this area of technology shows promise and is the subject of active research to enhance efficacy. Advantages & limitation of using cold plasma as a novel method if food industry. flexible sanitizing method uses electricity Eg: plasma torch. antimicrobial chemical agents are not required to inactivation prcess. Cost effective method compared to other chemical & thermal decontamination methods. Less time consuming method.( need few seconds to inactivate microbes within the food surface & mild surface) green technology ( since harmfull effects to environment has not idetified yet) Key limitations 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.

15 Applying cold plasma technology to Sri Lankan food industry. Adapting the technology for liquids could allow development of portable devices to clean drinking water in areas with contamination or that lack other purification methods or it can be used instead of using chlorination method. Also It could allow food processors to bottle juices or dairy industry without first heating them, a process widely used to kill bacteria that can alter products which is similar to pasteurization process.( however without the heat and quality changes that occur with that process.)

16 References JOURNALS INTERNATIONAL JOURNAL OF EMEGING TRENDS IN ENGINEERING & DEVLOPMENT JOURNAL OF FOOD ENGINEERING E-BOOKS TRENDS IN FOOD SCINECE & TECHNOLOGY BY S.K. Pankaj, C. Bueno-Ferrer, N.N. Misra, V. Milosavljević, C.P. O Donnell, P. Bourke, K.M. Keener, P.J. Cullen WEBSITES of_cold_plasma_technology_in_food_packaging strawberry-

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