Cost modelling of Pseudomonas fluorescens and Pseudomonas chlororaphis as biocontrol for competitive exclusion of Salmonella enterica on tomatoes

† All authors have contributed equally. N.B. Mention of trade names or commercial products is solely for the purpose of providing specific information and does not imply recommendation or endorsement by the U.S. Department of Agriculture (USDA) and the University of Maine. USDA is an equal opportunity provider and employer.

ABSTRACT

Published research on process-based models for biocontrol of foodborne pathogens on produce is limited. The aim of this research was to develop cost model estimates for competitive exclusion (CE) process using Pseudomonas fluorescens and Pseudomonas chlororaphis (non-plant pathogenic and non-human pathogen) as biocontrol against Salmonella enterica on tomatoes. Cost estimates were based on material inputs, equipment, facilities, and projected processing conditions of post-harvest packaging of tomatoes. The microbiological data for inactivation of S. enterica was based on published papers. The small-scale processing facility was assumed to have a processing capacity of 2000 kg of tomatoes/hour for 16 h per day, operational 6 days a week, and for 3-months /year. The large-scale facility was assumed to have a processing capacity of 100,000 kg of tomatoes/hour. Estimated initial capital investment costs for small and large-scale models (production facility) were US$391,000 and US$2.1 million. Application of CE for biocontrol of S. enterica on tomatoes was estimated at US$0.0058–0.073/kg of tomatoes during commercial processing operations. This exceeds chlorine wash technology estimated at US$0.00046/kg and is competitive with gaseous chlorine dioxide at US$0.02–0.21/kg. For high-value produce, CE may complement existing technologies increase food safety, reduce storage loses, and extend shelf life of produce.

KEYWORDS:

• Competitive exclusion
• biocontrol
• process model
• cost estimates
• green tomatoes
• Salmonella

Acknowledgements

We thank The USDA-ARS, Northern Regional Research Center, Peoria, IL and Dr David Weller of USDA-ARS, Biological Control Laboratory at Pullman, WA for supplying the isolates used in microbiological assays for biological control processes. We are grateful to Dr Kayimbi Tubajika for the review of this manuscript and for valuable comments.

Disclosure statement

No potential conflict of interest was reported by the authors.

Notes

† All authors have contributed equally. N.B. Mention of trade names or commercial products is solely for the purpose of providing specific information and does not imply recommendation or endorsement by the U.S. Department of Agriculture (USDA) and the University of Maine. USDA is an equal opportunity provider and employer.