Evaluation of the Physicochemical and Microbiological Quality of Cream Cakes Marketed in Trabzon: A Pearson Correlation and Principal Component Analysis (PCA) Approach

Abstract

Cream cakes are among ready-to-eat foods that are highly susceptible to microbial growth due to their high water activity, near-neutral pH values, and rich nutrient content. In this study, the physicochemical and microbiological properties of 15 cream cake samples collected from different sales points in the city center of Trabzon were evaluated. Within the scope of the research, analyses of dry matter, ash, pH, and water activity (aw) were performed on the samples, along with counts of total aerobic mesophilic bacteria (TAMB), total aerobic psychrophilic bacteria (TAPB), Enterobacteriaceae, coliform bacteria, yeast-mold, and Staphylococcus aureus. Additionally, the relationships between quality parameters were examined using Pearson correlation analysis and Principal Component Analysis (PCA). According to the results, dry matter, ash, pH, and water activity values ranged from 40.1–71.4%, 0.39–1.25%, 4.20–8.00, and 0.835–0.887, respectively. Microbiological analyses revealed that in some samples, TAMB, Enterobacteriaceae, yeast-mold, and S. aureus counts reached levels of 5.9, 5.7, 5.6, and 5.0 log CFU/g, respectively. In particular, the S. aureus loads detected in samples CC8, CC11, and CC12 exceeded the limits specified in the Turkish Food Codex Communiqué on Food Safety Criteria, posing a public health risk. Pearson correlation analysis showed a very strong positive correlation between Enterobacteriaceae and coliform bacteria (r = 0.98) and a strong positive correlation between yeast-mold and psychrophilic bacteria counts (r = 0.89). According to the PCA results, the first two principal components explained 64.59% of the total variance and demonstrated that microbiological load was one of the main factors in the discrimination of the samples. The findings indicate that cream cakes offered for sale in Trabzon exhibit insufficient microbiological quality and that improvements in production hygiene and cold chain practices are necessary.