Factors that influence the introduction, fate and mitigation of foodborne pathogens on mangoes throughout the production chain

Understanding the persistence and mitigation of foodborne pathogens on the surface of mangoes is essential to the establishment of Best Management Practices for the responsible handling, packing, distributing, and importing of mangoes, and is a fundamental management prerequisite to providing customers with safe mangoes. There is inadequate science-based data to establish management standards and criteria for mangoes to meet pending requirements of the Food Safety Modernization Act. The purpose of this research project is to evaluate the persistence of foodborne pathogens on the surfaces of whole and fresh-cut mangoes, assess potential mitigation strategies for control of pathogens on mango surfaces, and appraise the ability of Salmonella to infiltrate mangoes under standard packinghouse conditions and then to determine the fate of the internalized cells. The data resulting from the proposed research will specifically address data gaps the National Mango Board currently faces, and will provide research-based metrics to validate mitigation strategies.

Mangoes have previously been linked to outbreaks of salmonellosis in North America, and limited information about the persistence or control of foodborne pathogens on mangoes exists in the published literature. The objectives of this study are designed to generate a scientific basis for minimizing and controlling pathogen presence on fresh mangoes during postharvest packing, distribution, and retail. Three objectives are included in this proposal: 1) Evaluate the fate of foodborne pathogens on the surfaces of whole and fresh-cut mangoes; 2) Assess the risk of contamination with foodborne pathogens from practices that are common in mango packinghouses; and 3) Evaluate the ability of Salmonella to infiltrate mangoes, and then to determine the fate of the internalized cells. The majority of the work will focus on Salmonella and ‘Tommy Atkins’ mangoes, but experiments are proposed to also evaluate Shiga-toxin producing Escherichia coli, Listeria monocytogenes and Vibrio cholerae, as well as ‘Ataulfo’ and ‘Keitt’ mangoes. Currently, no scientific data exists to support postharvest intervention or a postharvest storage time for mangoes covered under the FSMA Produce Safety Rule that may have been exposed to water not meeting the standards currently in the proposed rule. For those packinghouses falling under the FSMA Preventive Controls Rule, the validation of risk-based preventive controls or processes will be key. The data generated in this proposal will specifically address these data gaps and will identify the appropriate pathogen of concern, and validated reduction strategies.

1. Evaluate the fate of foodborne pathogens on the surfaces of whole and fresh-cut mangoes. 

2. Assess the risks of contamination with foodborne pathogens from handling practices that are common in mango packinghouses. 

3. Evaluate the ability of Salmonella spp. to infiltrate into mangoes and to determine the fate of internalized cells after infiltration.

• No meaningful reductions of Salmonella or L. monocytogenes were observed on the surface of whole mangoes. These results imply that postharvest microbial reduction rates should not be relied on as a Corrective Measure to meet the Produce Safety Rule requirements for mangoes. 

• If control of bacterial hazards is identified during the cold chain as a Process Preventive Control in the Hazard Analysis of a Food Safety Plan for fresh-cut mangoes under the Preventive Controls for Human Foods Rule of FSMA, Salmonella, not L. monocytogenes, should be identified as the bacterial hazard, as it has the fastest growth rate. 

• Use of an overhead spray wash, with either PVC or brush rollers, can be used as a Corrective Measure as defined by the Produce Safety Rule, and as a Process Preventive Control as defined by the Preventive Controls for Human Food Rule. o Highest reductions are seen following 60 s with 100 ppm free chlorine and 80 ppm PAA. o Specific reductions needed in validations will be based on the roller type, sanitizer type, and contact time. 

• Salmonella populations present in hydrocooling water can internalize into mango flesh, and the internalization is variable depending on variety and if mangoes are cooled at ambient temperature prior to hydrocooling. Proper control of the sanitizer in hydrocooling water is needed to prevent internalization.