Microbiological quality of freshcut jackfruit and pineapple and the antimicrobial potential of organic acids and probiotics

摘要

Freshcut processing is useful for large, difficult-to-handle fruits such as jackfruit and pineapple, as it can cater to high consumer demand for convenient fresh products. Consequently, technological challenges become greater because freshcut produce deteriorates quickly and is susceptible to contamination by microorganisms. This study examined the microbial load on ripe 'EVIARC Sweet' jackfruit arils and 'Queen' pineapple slices from wet markets and supermarkets following standard sampling and platingmethods. The fresh cut products were then used to determine the efficacy of organic acids (1.5-2.5% ascorbic and lactic acids as 2-min dip) and probiotic lactic acid bacteria [Lactobacillus acidophilus and Lb. plantarum applied at 109 CFU mL~(-1) cell suspensionas 1-3% protected culture) in reducing microbial load and maintaining product quality. A 2 min wash in 150 ppm chlorine and the commercial probiotic formulation Protexin (10s CFU g-1) as protected culture served as control treatments. Product samples were packed in sterile resealable 50 urn-thick polyethylene bags and stored at 7-10°C for 5 days before evaluation. Coliform, aerobic bacteria and yeast and mold counts on freshcut pineapple and jackfruit from wet markets were 0.66-0.78 and 0.70-1.0 log higher than from supermarkets, respectively. Ascorbic acid at 2.5% and lactic acid at 1.5% significantly reduced total aerobic counts while lactic acid was more effective against coliforms as well as yeast and mold proliferation on both freshcuts.Probiotic treatment was generally less effective and Protexin had no significant effect. Lb. plantarum was more promising than Lb. acidophilus. Lb. plantarum at 3% was most effective against aerobic bacteria, coliform and yeast and mold proliferation. Inmost cases, the antimicrobial activities of organic adds and Lb. plantarum were comparable to or better than chlorine after five days of storage. The antimicrobial agents had no adverse effects on the physicochemical and sensory qualities of produce.