本研究旨在研究不同温度下加工日期糊和糖浆中沙门氏菌和单核细胞增生李斯特菌的行为。商业产品用大约6logCFU/mL肠球菌或单核细胞增生李斯特菌接种,并在4、10和24°C下储存90天。S.enterica能够在日期产品中存活,直到4°C储存结束。在这个温度下,椰枣浆中的数量减少了2.1logCFU/g,椰枣糖浆中的数量减少了3.4logCFU/g;然而,在10°C,细胞减少>4.2logCFU/g,通过直接铺板在日期糊中或通过在糖浆中富集(完全消除)检测不到.Further,在24°C,在30天和7天时,在日期糊和糖浆中实现了肠球菌的完全消除,分别。在4、10和24°C下储存90天的日期糊中,单核细胞增生李斯特菌的数量减少了1.4、4.4和>4.6logCFU/g,分别。在日期糖浆中,在4、10和24°C时,单核细胞增生李斯特菌的数量减少到50、14和4天,分别,通过直接电镀,在10和24°C下储存50和30天,观察到完全消除,分别。枣膏和糖浆的初始pH值分别为4.7和4.8,并且保持稳定直到储存结束,除了单核细胞增生李斯特菌接种的糖浆。实际应用:肠道沙门氏菌和单核细胞增生李斯特菌可以很容易地在枣膏和糖浆中存活,特别是在冰箱温度下,这解释了防止食源性病原体污染日期产品的必要性。
This study aimed to investigate the behavior of Salmonella enterica and Listeria monocytogenes in processed date paste and syrup at different temperatures. Commercial products were inoculated with approximately 6 log CFU/mL of S. enterica or L. monocytogenes and stored at 4, 10, and 24°C for 90 days. S. enterica was able to survive in date products until the end of storage at 4°C. At this temperature, numbers decreased by 2.1 log CFU/g in date paste and by 3.4 log CFU/g in date syrup; however, at 10°C, cells were reduced >4.2 log CFU/g and were undetectable by direct plating in date paste or by enrichment (complete elimination) in syrup. Further, at 24°C, complete elimination of S. enterica was achieved in date paste and syrup by 30 and 7 days, respectively. L. monocytogenes numbers decreased by 1.4, 4.4, and >4.6 log CFU/g in date paste stored at 4, 10, and 24°C for 90 days, respectively. In date syrup, numbers of L. monocytogenes decreased to undetectable levels by 50, 14, and 4 days at 4, 10, and 24°C, respectively, by direct plating and complete elimination was observed at 10 and 24°C by 50 and 30 days of storage, respectively. The initial pH values of date paste and syrup were 4.7 and 4.8, respectively, and remained stable until the end of storage except for L. monocytogenes-inoculated syrup. PRACTICAL APPLICATION: Salmonella enterica and Listeria monocytogenes can easily survive in date paste and syrup particularly at refrigerator temperature, which explains the necessity of preventing the contamination of date products with foodborne pathogens.