At ambient room temperature ($20-35^\circ\text{C}$), microbial spoilage of properly retorted cans almost invariably results from can seam leakage (leaker spoilage / post-processing can seam contamination) during cooling in untreated chlorination-deficient water, which permits non-sporeforming mesophiles (e.g., coliforms, micrococci, lactic acid bacteria) to enter. In contrast, underprocessing typically yields single heat-resistant sporeformers, and TA (thermophilic anaerobe) spoilage occurs only at elevated temperatures ($\gt 43-55^\circ\text{C}$).

Evaluating factors influencing microbial resistance:
Statement (A) is correct: Polysaccharide capsules shield bacteria from thermal penetration, chemical disinfectants, and phagocytosis.
Statement (B) is correct: High lipid and wax content in bacterial envelopes (as in Mycobacteria) confers substantial resistance to drying, heat, and chemical biocides.
Statement (C) is incorrect: Capsule formation confers protection, making cells harder, not easier, to kill.
Statement (D) is correct: Spherical cocci possess lower surface-area-to-volume ratios than elongated bacilli/rods, making vegetative cocci (such as Staphylococcus and Enterococcus) generally more resistant to heat, desiccation, and osmotic stress than vegetative rods.