Microbial and physiochemical quality of post harvest apples (Malus domestica Borkh) influenced by storage condition

This study assess the microbial and physiochemical quality of post-harvested apples (Malus domestica) under varying storage conditions, specifically ambient temperature and refrigeration temperature. Microbial analyses revealed distinct trends in bacterial and fungal counts. Standard microbiological and physiochemical techniques were adopted. For refrigerated apples, the total heterotrophic bacteria count peaked on Day 15 (1.8×105 CFU/g), contrasting with the lowest count on Day 3 (3.6×103 CFU/g). Similarly, ambient temperature of storage exhibited highest aerobic bacteria growth on Day 15 (3.3×104 CFU/g) and lowest on Day 2 (5.0×103 CFU/g). Staphylococcus counts in refrigerated apples peaked on Day 3 (3.6×103 CFU/g) and ambient temperature storage on Day 15 (7.4×103 CFU/g). The study identified seven bacterial genera, including Staphylococcus (19.6%), Bacillus (21.6%), and Proteus (17.6%) being prominent. Others were; 11.8% Micrococcus; 21.6% , Corynebacterium,; 13.7% Pseudomonas and 5.9% Citrobacter. Physiochemical attributes exhibited temperature-dependent variations. pH levels in refrigerated apples were lowest on Day 15 (2.88) and highest on Day 12 (3.80), whereas ambient temperature storage showed the highest pH (3.59) on Day 0 and lowest on Day 12 (3.42). Moisture content ranged from 80.2% (Day 3) to 87.8% (Day 15) for refrigerated apples, and from 85.7% (Day 1) to 87.8% (Day 15) for ambient temperature storage. Specific gravity decreased from 0.64 (Day 0) to 0.51 (Day 15) for refrigerated apples and from 0.64 (Day 0) to 0.59 (Day 15) for ambient temperature storage. Total suspended solids (TSS) fluctuated from 17.86% (Day 0) to 12.01% (Day 15) for ambient temperature and 12.54% (Day 15) for refrigerated temperature. The study recommends implementing optimized refrigeration protocols, considering the observed microbial growth patterns, could enhance the preservation of apples. While emphasizing stringent hygiene practices within storage facilities to be crucial, regular cleaning and disinfection routines even in refrigerators is a necessity.