There are high chances of cross-contamination by workers due to the manual processing process in simple processed fishery products. As a result of poor safety management among workers, these processed fishery products are likely to get contaminated by foodborne pathogenic bacteria such as Staphylococcus aureus. In addition, the frequency of S. aureus detection in simple processed fishery products is high due to the analysis of samples and final products. The source of S. aureus contamination is mainly from its parasitism on the workers’ skin. In the present study, we collected simple processed marine products which are processed by workers at different time intervals and these products were also analyzed in order to check the S. aureus contamination. For this study, three shellfish processing plants include salted chub mackerel, frozen oysters, and shucked oyster, which are produced manually by most of the workers at different times such as 6 hours, 8 hours, and at the end of work. Total 103 samples were collected for the analysis of different microbiological hazards such as anaerobic bacterial count, coliform group, E. coli, S. aureus, Salmonella sp. and Listeria monocytogenes. The result showed that in salted chub mackerel-processing factory where worker changed their gloves every 2 hours, no hygienic indicator bacteria and pathogenic microorganisms were detected in all samples. In frozen oyster processing factory where the gloves were sterilized every 30 minutes, only S. aureus was detected. However, most of the samples were found to have high bacterial counts in the case of shucked oyster contained in poultry kidneys, which not reused and periodically replaced with new gloves. Therefore, considering the case of salted chub mackerel and frozen oysters, it is necessary to reinforce the workers hygiene safety management such as disinfection and replacement of gloves periodically in order to reduce the contamination of foodborne bacteria such as S. aureus.