Reduction of Escherichia coli, as a surrogate for Salmonella spp., on the surface of grapefruit during various packingline processes

• Published in: Food microbiology 2019-04, Vol.78, p.188-193
• Main Authors: Danyluk, Michelle D., Friedrich, Loretta M., Dunn, Laurel L., Zhang, Jiuxu, Ritenour, Mark A.
• Format: Article
• Language: English
• Subjects: Citrus; Citrus paradisi - microbiology; Colony Count, Microbial; Corrective measures; E. coli; Escherichia coli O157 - isolation & purification; Food Handling; Food Microbiology; Food Packaging; Fruit - microbiology; Grapefruit; Packingline; Salmonella; Salmonella - isolation & purification; Temperature; Validation
• ISSN: 0740-0020; 1095-9998
• DOI: 10.1016/j.fm.2018.10.014

The US Produce Safety Rule allows for use of water that does not meet its microbial standards if corrective measures are employed. This research was initiated to determine the suitability of nonpathogenic Escherichia coli as a surrogate for Salmonella during citrus washing, and to evaluate the removal of E. coli from grapefruit on two pilot packinglines (CREC and IRREC) as corrective measures. Whole grapefruit were inoculated with either E. coli or Salmonella and dried, and exposed to a variety of treatments on a lab-scale brush wash system. Individual processes were evaluated on the pilot packinglines with E. coli only. In all lab-scale brush wash system treatments, bacterial population reductions between E. coli and Salmonella were not significantly different (P ≤ 0.05). On pilot packinglines, E. coli populations were reduced by 3.59 to >5.11 log CFU/grapefruit at the CREC packingline, and by 3.30 to >5.13 log CFU/grapefruit at the IRREC packingline. Treatment of fruit through complete packingline processing at both locations reduced E. coli populations to levels below the detection limit (5.0 log CFU/fruit.•Background populations were reduced from 0.6 to 4.0 log CFU/grapefruit.