Food Processing

Food production

Air quality and the risk of surface contamination play a vital role for food processing, production, packaging as well as growing and storage of fruits and vegetables. UV sterilization of both the air and/or the surface of the product and packaging can dramatically reduce the possibilities of contamination and can extend produce shelf-life by destroying the off-gassing (i.e. ethylene) that causes produce to age faster.

BENEFITS

  • Dramatically improve facilities’ Indoor Air Quality by destroying airborne bio-chemical contaminants such as viruses, bacteria, mould and chemicals which may result in surface contamination and pre-mature aging of fruits and vegetables
  • Surface sterilization of products and packaging (i.e. eradicate listeria from meat surfaces)
  • Incorporate UV fixtures into the production line (i.e. over conveyer belts) to bask the products and surfaces prior to packaging maintaining a sterile product ready for distribution or consumption<
  • UV Lamp Systems that use TEFLON coating to prevent any UV Lamp contents from escaping in the event of Lamp breakage
  • Reduce or eliminate unpleasant odors which may result from outside air or re-circulated air within the building
  • Improve equipment efficiency while reducing energy costs
  • Maintain a clean evaporator coil saving time and resources on coil cleaning
  • Combination UV /HEPA Stand-Alone Systems designed for particulate filtration and UV sterilization
  • UVC has been tested by the EPA & National Homeland Security
  • A “Green” Technology

Some examples on the antimicrobial and hormetic effects of UV radiation treatment on fresh produce are listed in the following table.

UV-C Radiation Effects on Fresh Produce

TOMATO

UV-C light can improve the nutritional value and increase the lycopene level without modifying the physical properties of tomatoes during postharvest storage. At low concentrations (about 4 kJ/m2), the UV-C radiation can induce the expression of a number of defence response genes, and suppress the expression of genes involved in cell wall disassembly, lipid metabolism and photosynthesis. The defence response genes delay the tissue softening, preserve the nutritional and sensory attributes, thus they let to extend the shelf-life of tomato fruit.

MUSHROOMS

UV-C radiation has an antimicrobial effect, thus it could be applied as a sanitizer tool on mushrooms. UV-C radiation at doses of 0.45-3.15 kJ/m2 let to reduce Escherichia coli O157:H7 by 0.67-1.13 log CFU/g.

BABY SPINACH

UV-C radiation applied at proper doses and to both sides of the baby spinaches could reduce microbial growth and extend the shelf-life without compromising the fresh-cut baby spinach quality. UV-C radiation at doses from 2.4 to 24 kJ/m2 can limit the growth of Listeria monocytogenes,Salmonella enterica, Pseudomonas marginalis, psychrotrophic andEnterobacteriaceae. However, UV-C light applied at low doses is effective on initial microbial reduction at the beginning of storage, for this reason the fresh-cut spinach shelf-life varies from 4 to 5 days at 5°C.

BROCCOLI

Floret yellowing is a serious critical issue limiting the shelf-life and quality of broccoli. UV-C radiation applied at doses from 4 to 14 kJ/m2 can retard the chlorophyll degradation and increase the antioxidant activity in the vegetable.

PEPPER

UV-C light can reduce the incidence and the severity of chilling injuries on pepper during postharvest storage at low temperatures. UV-C radiation applied at dose of 7 kJ/m2 can retard the symptoms due to chilling injury and  maintain the tissue firmness.

STRAWBERRY

UV-C radiation applied at doses from 0.43 to 4.30 kJ/m2 can delay the tissue softening acting on antioxidant and enzymatic activity in strawberry. UV-C light treatment at hormetic doses induces the expression of the defence response genes, which stop the cell wall degradation controlling the softening or defend the strawberry fruit against infections, such as the gray mold caused by Botrytis cinerea.

BLUEBERRY

UV-C radiation can reduce the berries decay caused by ripe rot (Colletotrichum acutatum) and enhance the antioxidant compounds level, such as total anthocyanin and total phenolics. The optimal UV-C doses to improve the phytochemical properties of blueberries range from 2.15 to 4.30 kJ/m2.

APPLE

UV-C radiation applied at the dose of 1.2 kJ/m2 can sanitize the apple surface, stop the oxidative enzymes, prevent tissue browning and off-odors development. In addition, UV light creates a dried protective film which inhibits microbial growth and juice leakage, this film is not perceived by consumer.

WATERMELON

UV-C radiation applied at doses from 1.4 to 2.8 kJ/m2 can reduce microbial growth and catalase enzyme activity on fresh-cut watermelon. However, the efficacy of UV-C light depends on initial microbial contamination and surface exposure to the treatment.

The authors of the review concluded that the UV radiation efficacy in prolonging the fresh produce shelf-life depends on produce (species and variety, intact or minimally processed fruit and vegetables), initial microbial contamination, UV light application system (moment of application, duration and dose of treatment) and on plant surface exposed to the irradiation.

UV-C radiation represents a valid alternative to the sanitizers currently used, which may release residues on the product or altering its quality, however monitoring of UV applications is still necessary as the efficacy of UV treatment can change according to the type of fruit or vegetable.