P3-103 Assessing the Microbiological and Physicochemical Characteristics of Processing Water and Their Impact on Safety of Ready-to-Eat Vegetables

Wednesday, July 31, 2013
Exhibit Hall (Charlotte Convention Center)
Daniele Maffei, University of So Pulo, So Pulo, Brazil
Anderson Sant'Ana, University of So Paulo, So Paulo, Brazil
Ana Carolina Perez, University of So Paulo, So Paulo, Brazil
Fabiana Silva, University of So Paulo, So Paulo, Brazil
Bernadette D.G.M. Franco, University of So Paulo, So Paulo, Brazil
Introduction: Water used in processing of ready-to-eat vegetables (RTEV) plays an important role in the quality and safety of the final product.

Purpose: This study aimed at assessing the impact of the physicochemical and microbiological characteristics of water used in RTEV processing plants on their safety.

Methods: A total of 34 water samples, collected from the tap water supply (n = 10), pre-washing (n = 9), washing (n = 10) and rinsing water tanks (n = 5) in ten RTEV processing plants located in the State of Sao Paulo, Brazil were tested for temperature, pH, organic load (mg/l), chlorine concentration (mg/l), redox potential (mV) and conductivity (s/cm). Vegetable samples were collected before (n = 36) and after (n = 48) washing step. All water and vegetable samples were submitted to counts of mesophiles, yeasts and molds (except for water samples), Enterobacteriaceae, total coliforms and E. coli. Presence of Salmonella was also investigated.

Results: Enterobacteriaceae and total coliforms were found in water samples collected from the pre-washing, washing and rinsing water tanks, in counts varying from 1.0-3.7 log CFU/g and 2.2->23 MPN/g. Pre-washing and rinsing water also contained E. coli (6.9->23 MPN/g). pH, conductivity and redox potential varied between 6.2-7.6, 125-216 s/cm, 324-529 mV. Counts of mesophiles, yeasts and molds, Enterobacteriaceae and total coliforms in final products processed with ozonated or refrigerated water (9.5°C or 12.3°C) varied between 1.6-4.4 and 2.0-4.3 log CFU/g or MPN/g. These counts were significantly lower (P < 0.05) than in final product processed with water containing only chlorine-based sanitizers (50-240 mg/l) or with non-refrigerated water at the washing-disinfection step. Overall, the processing caused 0.5 to 1 log CFU/g or MPN/g reductions in the counts of mesophiles, yeasts and molds, Enterobacteriaceae, total coliforms and E. coli in the RTEV. Salmonellawas not detected in any water or RTEV sample.

Significance: Our data indicate that water characteristics and practices applied during RTEV processing influence microbial quality of these products.