Page 32 - FoodFocusThailand No.218 MAY 2024

SPECIAL FOCUS

water medium. The heat consumption of HPTP is lower than freshness. The electrostatic field is suitable for preserving
pasteurization and ten production times shorter than perishable food and is divided into two patterns: low and
conventional canned food. It can be applied in a wide range of high-voltage. The high-voltage provides more than 10 kV/m;
foods, for example, green peas with ham, steamed meat, therefore, it is a short time consumption, convenient, and
vegetable soups, and baby meals. The advantage of this maintains overall quality. Nonetheless, this pattern may be a
process is the suppression of pathogens and microbial spores risk of electric shock. While a low voltage is a safe and more
only through controlling the pressure and temperature, so low- acceptable level. Fresh fruits and vegetables normally contain
acid foods are stable during storage and lead to sterilization biologically active substances that are electrically charged.
for commercial products. When these raw materials are placed in an electric field
between parallel electrodes as a strong electric field source,
the charge will move and cause energy distribution within the
fruit and vegetable cells. These phenomena can inhibit
biochemical reactions after harvesting; meanwhile, electric
fields also create the ionization of surrounding air, which affects
microorganisms. In particular, fresh broccoli treated with high
electrostatic field technology of 50-400 kV/m at a temperature
of 4 C can maintain its hardness, green color, and freshness
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for up to 40 days. Using a low-voltage electrostatic field
technique of 500 V in strawberries can delay spoilage for up
to 10 days.

Expanding Food Preservation with Microwaves
Microwave pasteurization of packaged food has shortened
processing time. Consequently, it is suitable for several foods
such as pre-packaged ones that are heat sensitive, high
viscosity food, semi-solid food, solid food, and ready-to-eat
Replacement of Hazardous Substances with meals containing many components. The microwave system
consists of a horizontal cylindrical pressure vessel with internal
Ozone
Ozone is a gas consisting of three oxygen atoms. The United equipment categorized into four sections: pre-heat,
equilibrating, holding, and cooling. Two microwave frequency
States Department of Agriculture (USDA) and the Food and
Drug Administration (FDA) have certified ozone as a safe levels are used in the food products: 915 and 2,450 MHz.
A frequency of 915 MHz is utilized for the production of
solvent (GRAS) to be used against airborne and foodborne
pathogens. Ozone is beneficial in both production and in-package meals ranging from 300 - 2,500 grams. This
frequency has penetrated deeper into the food than the 2,450
packaging, especially in maintaining the quality of post-harvest
agricultural products like vegetables and fruits. Because the MHz frequency and provides a consistent temperature. For
instance, the production of ready-to-eat pasta using a
preparation of fresh-cut fruits causes physical changes and
tissue damage, which facilitates the growth of microorganisms, microwave system started with loading pasta into the tray,
sealing it, and then pre-heating it at 60 C for 40 minutes.
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it is necessary for proper preparation. Chlorine solutions are
often used in the food industry for washing fruits and vegetables. After that, the heated pasta is pasteurized by a 4.5 KW
microwave under a frequency of 915 MHz at a rate of
However, chlorine brings about the residue of trihalomethanes,
which is classified as a carcinogen. Thus, ozone is an 76.2 cm/min until the cold point reaches a temperature of
86 C. This tray was held at 90 C for 10 minutes before being
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alternative option to eliminate microorganisms and reduce the o
production of ethylene gas in fruits. For instance, spinach has cooled down to 23 C for 5 minutes, resulting in a total of
65 minutes of processing time. Currently, advances in
a longer shelf life when treated with ozone water at a
concentration of 3 ppm for 4 minutes under a temperature of microwave technology are being applied to the development
of high-moisture ready-to-eat meals for astronauts. This is
4 C. It can inhibit ethylene gas during storage for up to 7 days.
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Additionally, ozone is also applied to control the quality of fruit because these prepared meals are the only source of energy
that is free of microorganisms and long storage for at least
juice. The pasteurization of juice often uses ozone in a gas
form. Using ozone gas with a concentration of 860 ppm for 28 3-5 years. Microwave technology is feasible in terms of
production and selection of appropriate packaging to extend
minutes can extend the shelf life of apple juice for 21 days, as
well as applying ozone gas to both clear and cloudy watermelon shelf life and be convenient for consumption.
Ready-to-eat food in Thailand has continued growth in
juice for 25 minutes can kill yeast and mold.
both domestic production and export to foreign markets. These
Retard the Deterioration with Electrostatic Field foods provide convenience for consumers and are beneficial
Techniques to producers for long-distance transportation. Therefore,
matching production technology with food suitably is important
Electrostatic field technology is a non-thermal process that can
preserve flavor, nutritional, and sensory qualities as well as to maintain food safety and prolong shelf life.
inhibit enzyme activity and microorganisms’ growth both inside
and outside the food. This technology differs from traditional
thermal processes; thus, it can prolong shelf life and maintain
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