Improving market access for smallholder farmers : socio-economic determinants of pre-and post-harvest practices - and their potential role for microbial contamination of fresh produce.

Abstract

Fresh produce is known to carry a natural microbial community however, during agricultural production and processing, any ready-to-eat fresh produce can become contaminated with pathogenic microbial organisms if inappropriate hygiene practices are used. As such fresh produce items go through minimal, if any inactivation or preservation treatments during further processing, hygiene quality and safety of the produce may be compromised thereby limiting market access and endangering consumer health. This study was conducted to determine if the Marianhill Agri-hub smallholder farmer socio-economic characteristics influence pre- and post-harvest practices and hygiene practices adopted. Furthermore, the contributions of these practices to microbial contamination of ready-to-eat fresh produce and its implications for market access, health and household food security were evaluated. Questionnaire results indicated a literate farmer community (88%), reliant on diversified income sources and farming as a livelihood strategy. Moderate interest in gaining market access to supplement household income was a key characteristic (61%). Most farmers utilized natural water sources (Mnini pond, Mnini river, stream and rain-fed) for irrigation, however, only a few (18%) pre-treated water prior to irrigation. Statistical analysis (Pearson Chi-square tests) indicated that farmer education levels and exposure to prior training have a statistically significant (p<0.05) impact on selected pre-and post-harvest practices implemented, highlighting the importance of farmer education and training. Microbiological analysis of fresh produce samples such as lettuce, parsley, carrots and spinach collected over at least a three month period from the main Agri-hub, showed the presence of total (ranging from 130-79000 MPN/g) and faecal coliforms (ranging from 22-1400 MPN/g) as well as E. coli (ranging from 2.2-49 MPN/g). These values were not satisfactory with respect to total coliform levels and presence of E.coli in view of South African legislation. In irrigation water samples, faecal coliforms were present up to 7000 MPN/100ml thereby frequently not meeting the WHO irrigation water quality requirements. Additionally, a number of irrigation water samples did not meet the South African standards for irrigation water applied to minimally-processed fresh produce of ≤ 1 E. coli/100ml, with values between 9.3-1400 MPN/100ml. Salmonella spp. was not detected in fresh produce and irrigation water samples. Antibiotic susceptibility patterns of 155 randomly selected E. coli isolates from both fresh produce and irrigation water were determined using the EUCAST disk diffusion method. The highest percentage of antibiotic resistance in E.coli isolates was detected against the antibiotic streptomycin at >94%. However, while 6% of the tested E. coli isolates were susceptible to all tested antibiotics, 2% of the E. coli isolates were multidrug-resistant. Multidrug-resistant strains of E. coli are concerning, as resistance genes are easily transferable to other potentially pathogenic bacteria present on produce, which might render the treatment of such pathogens difficult. Scanning Electron Microscopy showed the ability of E.coli isolates to form biofilms on PVC coupons mimicking contact surfaces. Antibiotic resistant and biofilm forming E.coli isolated from fresh produce and associated production and processing surfaces highlight the need of implementation of appropriate pre-and post-harvest hygiene practices. Stringent microbiological quality standards governing entry into high-value markets need to be adhered to by smallholder farmers. Therefore, understanding of smallholder farmer socio-economics is imperative to improving pre-and post-harvest hygiene practices, as the use of proper hygienic pre-and post-harvest practices is essential to prevent microbial contamination and improve quality of ready-to-eat fresh produce which will, in turn, facilitate improved market access.