寿命可靠性计算在食品货架期分析中的初步应用

以市售灭菌乳为研究对象,应用Weibull模型通过对食品非感官指标的分析,预测食品的货架期。灭菌乳分别在25、30、35、40℃环境下恒温储藏45d,并定期随机抽样进行感官检验和测定酸度。应用Weibull hazard analysis(WHA)方法分析非感官试验数据来预测样品货架期,并进行了寿命可靠性分析。     

复合天然保鲜剂在低温肉制品保鲜中的应用试验

针对当前低温肉制品的保鲜难题,本试验利用丹尼斯克复合天然保鲜剂葆先丹PM21,在肉制品工厂烟熏烤肠中试中同现有的肉制品保鲜方案进行应用比较.恒温保藏研究证实,葆先丹PM21肉制品保鲜剂性能显著优于同类产品,在30天内能有效抑制低温烤肠微生物数量在国家标准范围之内,同时样品感官质量保持良好,具有良好的防腐性能价格比.     

烧鸡综合保鲜技术研究

根据栅栏因子保鲜理论,采用多种栅栏因子科学合理的组合,对烧鸡进行了综合保鲜研究。结果表明:复合防腐剂(Nisin0.05%、溶菌酶0.05%、乳酸钠2%和双乙酸钠1%)+真空包装+水浴热处理(85～90℃水浴杀菌30min,流水冷却30min)的综合保鲜技术可使烧鸡在常温下(15～20℃)贮藏60d。     

BOPP瓶装饮料货架期透氧性研究

以纯净水、茶饮料、果汁和加味水为试验对象,对BOPP瓶装饮料货架期透氧性进行研究,找出了BOPP透氧性的变化规律。     

基于特定致腐菌的调理肉饼货架期预测模型构建

为建立调理肉饼中特定致腐菌的货架期预测模型。将特定致腐菌乳酸菌接种于经臭氧减菌化处理的调理肉饼中,真空包装后分别于-1℃、4℃、10℃、15℃和22℃条件下(温度波动为±1℃)贮藏,在贮藏期间(0～11 d)测定调理肉饼挥发性盐基氮值、pH值、硫代巴比妥酸值及菌落总数等指标,并进行感官评价,利用修正的Gompertz方程和平方根模型(B?lehrádek),建立以特定致腐菌乳酸菌为关键品质因子的调理肉饼微生物货架期模型。结果表明:修正的Gompertz方程能较好地拟合不同贮藏温度下微生物的生长曲线,应用平方根模型(B?lehrádek)描述温度对最大比生长速率(μ_(max))和迟滞期(Lag)的影响,均表现出良好的线性关系(R~2分别为0.98和0.83)。调理肉饼在-1℃、4℃、10℃、15℃和22℃下乳酸菌货架期最小腐败量对数平均值为(6.94±0.21) lg(cfu/g),平均最大菌数对数值为(8.65±0.16)lg(cfu/g),得到了在-1℃～22℃贮藏温度下调理肉饼的货架期预测模型。预测模型通过10℃和15℃贮藏温度下的货架期实测值来进行验证,相对误差均小于10%,表明基于平方根方程建立的模型可以有效地预测调理肉饼在-1℃～22℃贮藏温度条件下的特定致腐菌乳酸菌的货架期。     

不同贮藏温度下稻花鸡肉优势腐败菌变化及Arrhenius货架期预测模型的建立

为获得稻花鸡肉腐败菌的Arrhenius货架期预测模型,采用培养基初步筛选与16S rDNA全基因序列鉴定优势腐败菌,研究不同贮藏温度（25、4、0℃）下优势腐败菌和菌落总数的生长变化,通过化学反应动力学方程构建菌落总数、假单胞菌和沙雷氏菌货架期预测模型并进行验证。结果表明,稻花鸡肉在贮藏过程中逐渐占主导地位的优势腐败菌是假单胞菌属莓实假单胞菌和肠杆菌科沙雷氏菌属液化沙雷氏菌。稻花鸡肉25℃常温贮藏下货架期不超过0.5 d,腐败中后期沙雷氏菌占主导地位,4℃冷藏保鲜货架期不超过4 d,假单胞菌和沙雷氏菌均随贮藏时间的延长呈增长趋势,0℃冰温贮藏货架期不超过10 d,贮藏后期假单胞菌和沙雷氏菌差异性不显著。利用菌落总数、假单胞菌、沙雷氏菌3个指标建立货架期预测模型,3种货架期预测模型预测值与实测值对比,平均相对误差均在允许范围内,预测效果最佳的是假单胞菌货架期预测模型。菌落总数、假单胞菌和沙雷氏菌货架期预测模型均能对稻花鸡肉的货架期进行真实预测。     

Effect of vacuum packaging on shelf-life extension of cooked and peeled harpiosquillid mantis shrimp (Harpiosquilla raphidea) during refrigerated storage

Effects of vacuum packaging (VP) on quality changes of cooked and peeled harpiosquillid mantis shrimp (HMS) during storage at 4 °C of 15 days were investigated. VP inhibited bacterial growth as ascertained by the lower rate of increases in total viable and psychrotrophic bacteria counts as well as other pathogenic and spoilage bacteria counts. VP samples had lower total volatile base and trimethylamine contents as compared to the sample packed in air (AP). Clostridium perfringens was undetectable in both samples. During storage, VP samples possessed lower pH than AP counterpart. Exudate and TCA-soluble peptide (TSP) contents of sample increased during the storage, regardless of packaging atmospheres. Fatty acid (FA) content, especially PUFA and MUFA, was decreased after 9 and 15 days of storage for AP and VP samples, respectively. The cooked and peeled HMS contained 32 volatile organic compounds, consisting of several aldehydes and alcohols. Carnobacterium and Pseudomonas were mainly involved in spoilage in samples as confirmed by next generation sequencing.     

Gas exchange in modified atmosphere packaging. 1: A new theoretical approach for micro-perforated packs

Gas transport and exchange through the perforations in micro-perforated packs used in modified atmosphere packaging were numerically modelled by using Stephan-Maxwell laws, and, outside these perforations, by Fick's law. the model accounts simultaneously for oxygen, carbon dioxide, nitrogen, argon and water vapour. Fruit and vegetable respiration was approximated by Michaelis-Menten kinetics depending on oxygen concentration with an uncompetitive inhibition due to carbon dioxide. Concentration equilibrium was reached after 2 to 3 days, depending on the void volume and on the diffusion properties of the packs. the equilibrium concentrations were dependent on the number of perforations, their diameter, the thickness of the film and the temperature. However, a pack which makes 10% oxygen possible within the pack at 10°C might induce anaerobiosis at 20°C.