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Title: EFFECT OF ACIDIFIED SODIUM CHLORITE APPLICATIONS ON MICROBIAL GROWTH AND THE QUALITY OF SHREDDED CARROTS

Author
item RUIZ-CRUZ, SAUL - CRFD, MEXICO
item Luo, Yaguang - Sunny
item GONZALEZ, ROLANDO - UMN
item TAO, YANG - UMD
item GONZALEZ, GUSTAV - CRFD, MEXICO

Submitted to: Journal of the Science of Food and Agriculture
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/17/2006
Publication Date: 11/22/2006
Citation: Ruiz-Cruz, S., Luo, Y., Gonzalez, R., Tao, Y., Gonzalez, G. 2006. Effect of acidified sodium chlorite applications on microbial growth and the quality of shredded carrots. Journal of the Science of Food and Agriculture. 86(12):188-1893.

Interpretive Summary: Food quality and safety are indivisible important attributes of a food product. It is therefore essential to evaluate the impact on both food quality and safety when devising a new technology. We previously identified a new sanitizer, acidified sodium chlorite (ASC), with a strong killing effect on human pathogenic bacteria on shredded carrots. It was a high potential for food safety applications. In this study, we investigated the effect of ASC applications on the food quality attributes of color, texture, pH, and overall visual appearance. The growth of spoilage microorganisms was also evaluated. We found that the effect of ASC on food quality and microbial growth was highly influenced by treatment concentration and exposure time; shredded carrots received the optimum ASC treatment had the best overall visual quality and the lowest microbial growth. These findings are important to the fresh-cut produce industry and sanitizer manufactures for developing new methods to improve food quality and safety.

Technical Abstract: The efficacy of acidified sodium chlorite (ASC) application at different concentrations on the physiological changes, microbial growth and quality of shredded carrots was evaluated. Shredded carrots were immersed for 1 min. in 100, 250, or 500 µl L-1 ASC solutions, or for 2 min in 200 µl L-1 chlorine or water control. Treated samples were spin-dried and packaged in polypropylene bags and stored at 5 °C for up to 21 days. At 7-day intervals, carrots were removed from the storage and evaluated for sensory quality, package atmosphere composition (O2 and CO2), product firmness, tissue electrolyte leakage and pH. The microbial growth including total aerobic bacteria counts, total coliforms/E. coli, molds and yeasts counts, and lactic acid bacteria counts, on the products was also determined. Treatments with all concentrations of ASC reduced 1.2 to 2.0 log cfu g-1 aerobic bacteria count, coliforms/E.coli counts, molds and yeasts counts, and lactic acid bacteria populations, compared with water washed and unwashed samples. During storage, shredded carrots received no wash treatment had a sharp increase in lactic acid bacteria populations accompanied by a sharp decline in pH readings and rapid loss in texture and tissue integrity; samples washed with 100 µl L-1 ASC maintained the best overall visual quality, accompanied by the retention of tissue integrity and texture. The treatment with 100 µl L-1 ASC was determined to be the optimum concentration of ASC for maintaining overall quality and firmness, inhibiting microbial growth, and prolonging shelf life of shredded carrots.