PETpla.net Insider 05 / 2021

PETplanet Insider Vol. 22 No. 05/21 www.petpla.net 37 TRADE SHOW REVIEW Solutions for extending shelf life of low-temperature fresh milk by Song Junjie, Director, Cheng Wenjie, Deputy General Manager and Zheng Lishen, Manager, Tech-Long The rapid development of cities, the rise of fresh food e-commerce and the improvement of cold chain fresh food logistics have contributed to the rising popularity of low-temperature fresh milk, which requires refrigeration, in many regions in China. It has a flavour close to fresh milk, has a fresher taste and nutrient loss is lower than that of normal temperature sterilised milk. Low-temperature fresh milk cur- rently accounts for about eight per cent of the entire domestic dairy product market, according to the Huajing Infor- mation Network; UHT normal tem- perature sterilised milk accounts for about 22%. As its nutritional and fresh characteristics meet consumer needs for healthy drinking, annual sales of fresh milk have been growing rapidly; at more than 10% since 2018. It has become a golden track that cannot be ignored in the dairy industry. Factors restricting development The shelf life of most low-tem- perature fresh milk on the market is limited by current production technol- ogy and is generally within three to seven days, with some up to 10 days or more. The short shelf life leads most low-temperature fresh milk sales to be regional. Production costs of traditional low-temperature fresh milk include packaging material, produc- tion equipment energy usage, sourc- ing, labour, product promotion and logistics. Disadvantages of traditional bottle dry production technology The traditional ultra-clean process sees the bottle sent first through the bottle loading platform/air duct/bottle unscrambler to the filling machine’s hydrogen peroxide sterilisation sta- tion. It then enters the hot air drying station to evaporate, dry and remove residue. The sterilised bottle then proceeds to the filling and capping machine. Cap sterilisation is usually by ultraviolet or pulsed light spectrum. Safety issues affecting shelf life The spectrum/ultraviolet method has a shadow effect, which means that sterilisation is incomplete, where light cannot be directly exposed to the thread of the cover. Light sterilisation has a poor killing effect on mould. As bottles can be loaded into the filling machine only by unscrambler, air duct, or manual bottle loading, it is difficult to avoid secondary pollution during the bottle transfer process. Dry sterilisation omits mechanical washing, which will affect the transfer process. Contami- nated debris is difficult to remove, and there are safety hazards. The space and internal surface area of large bot- tles, with capacities of over one litre, mean that sterilisation efficiency is difficult to guarantee. External clean- ing and disinfection of the equipment is usually done manually, which has been found to leave ‘dead’ corners, which have not been totally cleaned efficiently. The filling machine and capping machine are placed in the one-hundred-level space of the main machine. The filling environment inside the equipment is difficult to guarantee; it is easy for it to become to be envi- ronmentally compromised during the production process. Energy consumption The drying process after hydrogen peroxide sterilisation consumes a lot of electricity. Heat sterilisation and drying requires bottles to be heated, which restricts the latitude to reduce bottle weight and thus makes it impossible to reduce the amount (and therefore cost) of packaging materials. Total energy consumption for sterilisation and heat- ing of large bottles is very significant. High production costs and short shelf life of current production technology are the main factors restricting the develop- ment of low-temperature fresh milk. Tech-Long launches a PET bottle solution PET bottles have the following advantages, compared with HDPE bottles: The cost of raw materials is lower than that of HDPE; bottle weight is less, for the same capac- ity. PET is tougher and stronger, has better sealing performance, no leak- age of products, and less loss. The oxygen barrier is much better than HDPE, leading to better preserva- tion of taste and flavour are better preserved. Shelf life is longer, under the same storage conditions. Colour masterbatch can be added to PET, for a good light barrier effect for some photosensitive products. Tech-Long’s exhibition specialist Xuxiao at Chinaplas