IRTA, Food Safety Programme, Finca Camps i Armet s/n, E-17121 Monells, Spain.
Department of Nutrition, Food Sciences and Gastronomy, XaRTA, INSA, School of Pharmacy and Food Sciences, University of Barcelona, Avinguda Prat de la Riba, 171, E-08921 Santa Coloma de Gramenet, Spain.
Food Res Int. 2019 Dec;126:108578. doi: 10.1016/j.foodres.2019.108578. Epub 2019 Jul 22.
Temperature is one of the main factors governing the growth of microorganisms. The aim of the present study was to provide temperature conditions representative of the food products stored in domestic refrigerators and to assess the impact of the temperature (fluctuation) on the shelf-life of refrigerated cooked meat products, from the safety and the spoilage point of view. The analysis of the time-temperature profiles recorded from 160 domestic refrigerators of households from small (28%) and large (72%) municipalities in Catalonia (Spain) showed that the 24 h-mean temperature could be described by a normal distribution (mean = 5.4 °C, standard deviation = 2.3 °C) with a mean value within the upper limit of the appropriate storage temperature of refrigerated products (i.e. ≤6 °C). The impact of door openings or day and night was not significant. Temperature distribution showed differences depending on the season, being higher in the cold season than in the warm one. Noteworthy, refrigerators of elderly (≥ 65 years old) households showed a higher percentage of time at temperatures >8 °C in comparison with those of the general population. Overall, the 75th percentile of the distribution of the 24 h-mean temperature values was 6.7 °C. This study can be used as a scientific evidence of the consumer storage stage when food business operators or laboratories conduct shelf-life studies. According to the simulation of the growth of Listeria monocytogenes and lactic acid bacteria in cooked meat products, risk scenarios were identified in which the critical level of the pathogen could be reached before lactic acid bacteria achieved the spoilage level. The fluctuation of the refrigerator temperature ranged from 0.5 up to 12.2 °C within the 24 h-profile. The assessment of the safety of cooked meat products stored at constant temperature or under different time-temperature profiles showed that both the mean and the fluctuation of the profile had an impact on the shelf-life, which was higher at low temperatures. The improvement of the household refrigerated storage would be an effective way to increase food safety of refrigerated ready-to-eat food.
温度是影响微生物生长的主要因素之一。本研究旨在提供家庭冰箱中储存食品的代表性温度条件，并从安全性和变质的角度评估温度（波动）对冷藏熟肉制品保质期的影响。从加泰罗尼亚（西班牙）的小（28%）大和（72%）城市的 160 户家庭的 160 台家用冰箱中记录的时间-温度曲线的分析表明，24 小时平均温度可以用正态分布来描述（平均值为 5.4°C，标准差为 2.3°C），平均值在冷藏产品的适当储存温度上限内（即 ≤6°C）。门的开关或白天和黑夜的影响并不显著。温度分布因季节而异，冬季比夏季高。值得注意的是，与一般人群相比，≥65 岁的老年人家庭的冰箱在温度 >8°C 的时间百分比更高。总体而言，24 小时平均温度值分布的第 75 百分位数为 6.7°C。这项研究可以作为食品经营者或实验室进行保质期研究时消费者储存阶段的科学依据。根据熟肉制品中李斯特菌和乳酸菌生长的模拟，确定了风险情景，在这些情景中，在乳酸菌达到变质水平之前，病原体的临界水平可能会达到。冰箱温度的波动在 24 小时内从 0.5°C 到 12.2°C 不等。在恒温或不同时间-温度曲线下储存的熟肉制品的安全性评估表明，平均温度和温度曲线的波动都对保质期有影响，低温下的保质期更高。改善家庭冰箱冷藏储存将是提高冷藏即食食品安全性的有效途径。
