Μικροβιολογική ποιότητα μαρουλιού τριών διαφορετικών συστημάτων καλλιέργειας
Date Issued
2017
Author(s)
Advisor
Abstract
Fresh fruits and vegetables have a crucial role in human nutrition. However, food-borne diseases by eating contaminated fresh products of plant origin are a powerful barrier to ensure public health. Α holistic monitoring approach of their causative parameters, their sources of contamination and introduction of a uniform-targeted legislative framework on supply chain is required. The purpose of this study is to characterize and compare the microbiological quality of three cultivation systems operating in Cyprus, conventional, organic and aquaponics. Ιt is very important to ensure the microbiological safety of conventional and organic products available in the market and to assess the microbiological quality of aquaponics products. A comparison was made based on lettuce and irrigation water. All samples were obtained and analysed by validated I.S.O. microbiological methods. Overall, they have been collected 111 lettuce samples (36, 37 και 38 conventional, organic and aquaponics, respectively). Their edible part has analysed for the quantitive determination of Total Aerobic Count, Yeasts and Moulds, Enterobacteriaceae, Escherichia coli and Salmonella spp. The mean counts of Total Aerobic Count are 5.96±0.54log c.f.u./g, 6.36±0.49log c.f.u./g and 4.61±1.20log c.f.u./g for conventional, organic and aquaponics cultivated lettuce, respectively. The mean counts of Yeasts and Moulds are 4.29±0.36log c.f.u./g and 4.48±0.57log c.f.u./g and 3.96±0.78log c.f.u./g for conventional, organic and aquaponics cultivated lettuce, respectively. The mean counts of Enterobacteriaceae are 4.19±0.69log c.f.u./g, 4.57±0.73log c.f.u./g and 2.37±1.76log c.f.u./g for conventional, organic and aquaponics cultivated lettuce, respectively. The mean counts of Escherichia coli are 0.70±1.26log c.f.u./g and 0.52±1.11log c.f.u./g for conventional, organic cultivated lettuce, respectively. The mean count of Escherichia coli of aquaponics produced lettuce is under the detection limit. The results of quantitive determination for Salmonella spp. is under the detection limit. Moreover, they have been collected 17 irrigation water samples (7 and 10 samples of irrigation water used for soil substrate and as water substrate of aquaponics systems). They have been analysed for quantitive determination of Heterotrophic Bacteria Count of mammalian and environmental origin, Enterococcus spp. and Escherichia coli. The mean counts of Heterotrophic Bacteria Count of mammalian origin are 2,73±0,72log c.f.u./100ml and 2,89±2,03log c.f.u./100ml of irrigation water used for soil substrate and as water substrate of aquaponics agriculture, respectively. The mean counts of Heterotrophic Bacteria Count of environmental origin are 3,99±0,88log c.f.u./100ml and 4,04±0,94log c.f.u./100ml of irrigation water used for soil substrate and as water substrate of aquaponics agriculture, respectively. The mean counts of Escherichia coli of irrigation water for soil substrate are 1,20±0,95log c.f.u./100ml. The mean counts of Escherichia coli of irrigation as water substrate of aquaponics are under the detection limit. The mean counts of Enterococcus spp. are 2.28±1.27log c.f.u./100ml and 0,36±0,68lοg c.f.u./100ml of irrigation water used for soil substrate and as water substrate of aquaponics agriculture. The results of this study highlighted the contribution of both microbiological quality of water on microbiological quality of fresh lettuce. Finally, noteworthy is the fact of the absence of microbiological substantial difference in conventional and organic lettuces, the qualification of aquaponics lettuces as retail products and their superior microbiological quality.
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