The risk of pathogenic microbiological contamination of South African fresh fruit for the export and local market

Thesis (MScFoodSc)--Stellenbosch University, 2020.

ENGLISH ABSTRACT: In South Africa microbiological safety of fresh fruit is not verified independently, and microbiological safety of fruit depends on producers and implementers of food safety systems and food safety auditors. Research and documented outbreaks of food poison incidents indicates that pathogens such as Salmonella spp., Escherichia coli and Listeria monocytogenes are associated with the fruit production and packing environment. The mechanisms of contamination in these environments were well established, but the amount of fruit produced makes it difficult to determine risk by doing microbiological analysis on randomly drawn samples from export batches or consignments of fruit. This study investigated the microbiological safety of fresh fruit produced in South Africa. Results from microbiological testing on samples drawn from fruit exported to Indonesia, which was the only export market requiring batch microbiological analysis, was used. 2688 Samples were analysed, including citrus fruit, pome fruit and table grapes for the presence of Salmonella and E. coli. Only 3 pear samples tested positive for E. coli, but still within acceptable levels. This study also indicated that consumers need to be educated on food safety principles in selecting and consuming fresh fruit, as some fruit varieties proved to be at higher risk than others for example, melons were classified as high risk as opposed to citrus fruit which was of low risk. The study emphasized the importance of food safety programs in making sure that fresh fruit was produced and packed in environments where microbiological risks was managed. It also confirmed that environmental microbiological testing is the preferred tool in determining risk and prevention of microbiological contamination. A final important factor established was that implementers of food safety systems should have good knowledge of microbiological risks in their environments and be able to interpret microbiological analysis correctly to prevent contamination of fruit produced. Authorities evaluating the implementation of food safety systems should be equipped with suitable knowledge.

AFRIKAANSE OPSOMMING: In Suid Afrika word die mikrobiologiese veiligheid van vars vrugte nie deur ‘n onafhanklike regulerende instansie bepaal nie en die mikrobiologiese veiligheid van vrugte is afhanklik van produsente, die implimenteerders van voedselveiligheidsisteme en voedselveiligheids auditeurs. Navorsing en gedokumenteerde voedselvergiftigingsuitbrake dui daarop dat patogene soos Salmonella spp., Escherichia coli and Listeria monocytogenes dikwels geassosieer word met vrugte, vrugteproduksie en die pakhuis omgewing. Die meganismes van kontaminasie van vrugte en die produksie omgewing met hierdie patogene is bekend, maar die groot volumes vrugte wat geproduseer word maak dit moeilik om met mikrobiologiese toetse op monsters wat ewekansig uit hierdie groot volumes vrugte getrek word, presiese mikrobiologiese risiko of teenwoordigheid van patogene op uitvoer vragte vrugte te bepaal. Hierdie studie het die mikrobiologiese veiligheid van Suid Afrika se uitvoervrugte ondersoek. Die resultate van mikrobiologiese ontledings op vrugte bestem vir die Indonesiese uitvoermark was gebruik in die studie aangesien die mark die enigste mark is wat vereis dat vrugte mikrobiologiese ontledings moet ondergaan. 2688 vrugtemonsters (sitrus, kernvrugte en tafel druiwe) wat getoets was vir die teenwoordigheid van Salmonella en E. coli se resultate was nagegaan. Uit hierdie monsters was daar net 3 monsters wat positief getoets het vir E. coli, alhowel dit nog heeltemal binne aanvarbare norme was. Die studie het aangedui dat verbruiker opvoeding aangaande voedselveiligheids beginsels rondom vars produkte soos vrugte belangrik is aangesien die risiko van voedselvergiftiging gekoppel aan vrugte nie dieselfde is vir all vrugte nie en dat vrugte soos spanspek en avokados ‘n groter risiko het as bv. Sitrus vrugte en appels. Die studie het die belangrikheid van voedselveiligheids programme in die produksie sowel as pakhuis omgewing uitgelig sowel as die noodsaaklikheid van goeie voedselveilgheids opleiding en verantwoordelike produsente. Die studie het bevestig dat mikrobiologiese omgewings studies meer waarde het om potensieele bronne van mikrobiologiese kontaminasie te indentifiseer en dan te bestuur. Die laaste belangrike aspek wat uitgelig was, was dat die implimenteerders van voedselveiligheids sisteme besonder goeie kennis van die mikrobiologiese risiko’s veral in die produksie omgewing moet handhaaf en veral instaat moet wees om mikrobiologiese resultate korrek te kan interpreteer om moontlike kontaminasie van vrugte te kan voorkom. Dit is ook belangrik dat instellings verantwoordelik vir die implemntering van voedselveiligheid in die vrugte produksie omgewing baie goed opgelei moet wees.

Masters