Utilisation of antimicrobial agents at pre- or post-smoking processes was considered for the microbial quality of hot-smoked trout fillets prepared at plant scale. Potassium sorbate (PS) and sodium lactate (SL) were used separately or in combinations at 3% (w/v) in brine for pre-smoking or with spraying at post-smoking. Pre-smoking usage could reduce the total aerobic mesophilic bacteria (TAMB) values better than the post-smoking usage during storage. However, post-smoking application was more effective at preventing the moulds and yeasts (MY) growth. PS in brine at pre-smoking was most efficient, which could keep trout fillets for even four weeks at 6±1°C storage within the range of consumable limits. Additionally, PS usage reduced the contaminated bacterial diversity and especially eliminated the outgrowth of Serratia liquefaciens. As a conclusion, pre-smoking application repressed the contaminated microbial growth during the storage of smoked trout fillets, which may eliminate the microbial risks.