Assessment of bacterial contamination, physical quality, and internal pH (albumen and yolk) of table eggs in Khartoum North.

Table eggs are a vital dietary component owing to their nutritional value; however, bacterial contamination, particularly of eggshells, poses significant public health risks. In Sudan, these risks are exacerbated by inadequate hygiene, poor storage conditions, and limited regulatory oversight, which compromise egg safety in local markets. This preliminary, exploratory, cross-sectional, laboratory-based study aimed to evaluate bacterial contamination, assess physical characteristics, examine the pH of albumen and yolk, and investigate the associations among these factors in table eggs from Khartoum North. A total of 46 samples (three eggs per sample, totalling 138 eggs) were randomly collected from five types of retail outlets in Khartoum North in September 2020. Eggshell, albumen, and yolk samples were tested for aerobic bacterial contamination and total viable bacterial counts (TVC) using standard microbiological methods. Physical characteristics, including yolk colour, shell thickness, albumen height, shell strength, Haugh unit (HU), and albumen weight, were assessed using a Digital Egg Tester 6000, whereas pH levels were measured using a HI98107 pH meter. ANOVA and Pearson's correlation were used to evaluate relationships, and Bayesian statistics were applied to estimate the pH values. Eggshell contamination by Staphylococcus spp. is widespread. (89.1%), Corynebacterium spp. (23.9%) being the most prevalent, followed by Escherichia coli (19.5%) and Salmonella spp. (15.2%). No bacteria were isolated from the albumen or yolk. A significant positive correlation was observed between the TVC and albumen pH (r = 0.540, P < 0.001), whereas other internal traits showed weak, non-significant correlations. The physical classification identified Grade AA (32.6%), A (34.8%), and B (32.6%) eggs. Weak correlations were found between shell strength and HU (r = 0.155, 95% CI: -0.141 - 0.427, P = 0.302) and between egg weight and HU (r = - 0.175, 95% CI: -0.434-0.121, P = 0.244). ANOVA revealed no significant differences in shell strength (F = 2.622, P = 0.084) or thickness (F = 0.115, P = 0.892) across grades. Bayesian estimates showed slight pH increases from Grade AA to B in yolk (6.363-6.555; 95% CrIs: 6.135-6.791) and albumen (8.463-8.604; 95% CrIs: 8.013-9.071), but non-significant differences. However, the overlapping CrIs indicated that these differences were not significant. The presence of Staphylococcus and E. coli on eggshells indicates inadequate hygiene. Bacterial load is linked to albumen pH, indicating that external microbes influence internal composition. Quality variations were observed based on egg grade and source, with contamination undermining the internal defences. Albumen pH is an indicator of freshness. Monitoring the shells and conducting physicochemical tests could enhance the traditional methods. Policymakers must enforce standards to ensure the safety of eggs. Given the preliminary and exploratory nature of this study, coupled with the limitations of a small and uneven sample size, the findings should be interpreted with caution. These results are meant to generate hypotheses, highlighting the need for further research with larger, more representative samples, balanced sampling strategies, and more comprehensive methods. Such efforts are crucial for validating and expanding these observations and deepening our understanding of bacterial contamination and egg quality.