In each food business, a food safety culture (FSC) with a certain maturity level prevails. Previous research has demonstrated that the maturity level of the prevailing FSC can be assessed, but empirical proof of FSC maturity improvement remains limited especially in food processing companies. This study aimed to zoom in on the food safety culture improvement trajectory of four food processing case studies, focusing on human-organizational dimensions of food safety culture. First, a pre-assessment of the maturity of the prevailing food safety culture was executed in each case company (assessment time 1) by application of a validated mixed-methods methodology which includes three different tools (the food safety climate questionnaire, management interview, and on-site evidence collection visits). Based on this pre-assessment, underdeveloped dimensions or gaps in the prevailing food safety culture were identified to find improvement needs. In each of the 4 included distinct case companies, an intervention was implemented. In the first case company, case 1, a food safety key performance indicator (KPI) system was implemented as the intervention, with shared monitoring and shared responsibilities for KPI improvement. Coincidentally, case company 2 and case company 4 selected the same intervention. Case 2, as well as case 4, decided to implement structured group discussions with operators to collect input for collaborative action point selection, aiming for their active involvement in food safety. In case 3, a food safety culture check system was implemented for systematic reward and recognition. After intervention implementation, the post-assessment was conducted (assessment time 2), applying the exact same methodology as the pre-assessment. To investigate the extent of improvement, comparison of the pre- and post-assessment in each of the four cases was first done descriptively by comparing the means. Next, data collected via the food safety climate questionnaire was compared statistically via Mann-Whitney U tests. Analyses showed a substantial objective and subjective (employees’ perceptions) improvement of the targeted food safety culture gaps in companies 1 and 2, demonstrating that food safety culture improvement was achievable through a science-based and cocreated intervention process and implementation plan compliance. In cases 3 and 4, marginal improvements and unchanged scores were revealed. Comparison of cases’ trajectory characteristics and resulting success rates demonstrated that senior management involvement was essential for interventional success, as well as implementing culture interventions on an organizational or group level, instead of only including selected employees.