Awaad Shimaa S, Sherief Marwa A, Mousa Sahar M, Orabi A, Abdel-Salam Ayah B
Department of Food Hygiene and Control, Faculty of Veterinary Medicine, Cairo University, Giza, Egypt.
Inorganic Chemistry Department, Advanced Materials Technology and Mineral Resources Research Institute, National Research Centre, Giza, Egypt.
Vet World. 2023 Sep;16(9):1991-2001. doi: 10.14202/vetworld.2023.1991-2001. Epub 2023 Sep 23.
Yeasts are common contaminants in the cheese industry, which frequently arise from raw milk, the surrounding environment, and equipment, resulting in economic losses in addition to health hazards. This study aimed to compare the antifungal effect of chitosan and nano-chitosan as natural preservatives with a commonly used chemical preservative (potassium sorbate) against and .
Laboratory Karish cheese was manufactured with the addition of potassium sorbate, chitosan, nano-chitosan, and their combinations at different concentrations. The survival of and was monitored in different treatments (CR, PR1, PR2, CR1, CR2, NR1, NR2, MR, CC, PC1, PC2, CC1, CC2, NC1, NC2, MC) during storage in a refrigerator with continuous measurement of pH. The impact of using these antifungal agents on the organoleptic parameters of Karish cheese during storage was also evaluated.
There was a significant decrease in the count of yeasts in all treatments from the 3 day of storage, while the mixture of 0.1% potassium sorbate (MR) and 2% chitosan (MC) improved the antifungal effect of chitosan with a lower potassium sorbate concentration and showed the best antifungal effects against both and . This combination reduced the yeast count from 8.92 and 9.57 log colony-forming unit (CFU)/g in MR and MC treatments, respectively, until it became undetectable on the 9 day of storage, which was earlier than for all other treatments. It was noted that the addition of chitosan nanoparticles (ChNPs) at either 0.25% (NR1 and NC1) or 0.5% (NR2 and NC2) during the manufacturing of Karish cheese significantly lowered the counts of and compared with chitosan with a higher molecular weight, but significantly lower than potassium sorbate until 6 day of storage as all treatments of chitosan nanoparticles became significantly higher than potassium sorbate treatments. After 9 days of storage, NR2 and NC2 treatments showed the most significant decreases in count (3.78 and 4.93 log CFU/g, respectively), indicating better stability of ChNPs. At the end of the storage period, PR2, PC2, CR2, and CC2 showed significantly high pH values among the groups of 4.8, 5.0, 4.8, and 5.1, respectively. The overall acceptability was significantly higher in treated Karish cheese samples than in the control group, especially at the end of the storage period.
Potassium sorbate, chitosan, and ChNPs are effective antifungal preservatives against and . In addition, the combination of chitosan with potassium sorbate showed synergistic antifungal activity. These additives also preserve the sensorial criteria longer than for cheese without preservatives.
酵母是奶酪行业常见的污染物，常源自原料奶、周围环境及设备，不仅会造成健康危害，还会导致经济损失。本研究旨在比较壳聚糖和纳米壳聚糖作为天然防腐剂与常用化学防腐剂（山梨酸钾）对[具体菌种1]和[具体菌种2]的抗真菌效果。
制作实验室卡瑞什奶酪时添加不同浓度的山梨酸钾、壳聚糖、纳米壳聚糖及其组合。在冰箱储存期间，监测不同处理组（CR、PR1、PR2、CR1、CR2、NR1、NR2、MR、CC、PC1、PC2、CC1、CC2、NC1、NC2、MC）中[具体菌种1]和[具体菌种2]的存活情况，并持续测量pH值。还评估了使用这些抗真菌剂对储存期间卡瑞什奶酪感官参数的影响。
从储存第3天起，所有处理组中的酵母数量均显著减少，而0.1%山梨酸钾（MR）和2%壳聚糖（MC）的混合物以较低的山梨酸钾浓度提高了壳聚糖的抗真菌效果，对[具体菌种1]和[具体菌种2]均显示出最佳抗真菌效果。该组合使MR和MC处理组中的酵母数量分别从8.92和9.57 log菌落形成单位（CFU）/g降至储存第9天时检测不到，比所有其他处理组更早。值得注意 的是，在制作卡瑞什奶酪时添加0.25%（NR1和NC1）或0.5%（NR2和NC2）的壳聚糖纳米颗粒（ChNPs），与较高分子量的壳聚糖相比，显著降低了[具体菌种1]和[具体菌种2]的数量，但在储存6天前显著低于山梨酸钾，因为所有壳聚糖纳米颗粒处理组的数量后来都显著高于山梨酸钾处理组。储存9天后，NR2和NC2处理组的数量下降最为显著（分别为3.78和4.93 log CFU/g），表明ChNPs具有更好的稳定性。在储存期结束时，PR2、PC2、CR2和CC2组的pH值分别显著高于其他组，为4.8、5.0、4.8和5.1。处理后的卡瑞什奶酪样品的总体可接受性显著高于对照组，尤其是在储存期结束时。
山梨酸钾、壳聚糖和ChNPs是针对[具体菌种1]和[具体菌种2]的有效抗真菌防腐剂。此外，壳聚糖与山梨酸钾的组合显示出协同抗真菌活性。这些添加剂还比未添加防腐剂的奶酪更长时间地保持感官标准。
