In filling lines, even those featuring advanced technologies, containers sterility is a critical issue of the whole production process, especially in the case of delicate and perishable products requiring a long shelf-life while leaving their organoleptic properties unchanged . As a matter of fact, containers that are not properly decontaminated and sterilized, make the whole filling process futile, and generate products deprived of the characteristics required by the current legislation. Promec has decided to face these problems investing in two directions: ultraclean and aseptic. For an effective sterilisation, top of the range machines use peracetic acid (APA) and peroxide, or hydrogen peroxide (H2O2), perfect for containers used to fill milk, dairy products or fruit juice.
Peracetic Acid: an effective biocide
Peracetic Acid (obtained by combining acetic acid and hydrogen peroxide) is an effective biocide with high oxidising power and stability, even at low concentration levels. Since it is active on a broad range of cases, it rapidly destroys spores, viruses, algae, moulds, microbacteria and yeasts. The sterilization and reaction time varies according to the product to be handled and the required decontamination level (even exceeding Log6). Evolution Twin HF is a monobloc machine that uses APA for sterilization, designed in full compliance with EHEDG and FDA regulations. High-flow valves allow production outputs up to 70,000 bph. The two carrousels are equipped with special grippers that pick the bottles by the neck and turn them upside down for strong sanitation before filling. During the first stage, bottles are sterilized inside and outside by means of a peracetic acid oxidizing solution with a concentration between 1,500 and 2,000 ppm at a temperature of 48-52°C degrees. After the sterilization, bottles are conveyed to the rinsing area by means of star-wheels that grip them from the neck, in order to remove any possible trace of APA with sterile water.
Hydrogen peroxide: total sanitation
Ideal for all types of containers, Steril-EV is a rotary sterilizer using hydrogen peroxide in its liquid state. During the initial phase, the container is preheated with hot air in the infeed star-wheel of the machine, where the injection of hydrogen peroxide, at a concentration of 30%, takes place. The oxygenated water is injected through atomizer nozzles so as to totally cover the internal wall of the container with a thin film, considerably reducing the quantity required for each container (0,5÷2 ml). These small quantities of hydrogen peroxide are injected very quickly (a few tenths of a second), at time intervals that are extremely difficult to control with mechanically-operated spraying valves. For this reason, the various cycles are entirely controlled by an electronic system; each nozzle is supplied by two solenoid valves (one for hot air and the other for peroxide), activated, in turn, by the PLC, which controls all the phases of the machine. At the end of the first phase, the containers enter the rotating carousel where the peroxide activation phase is started using hot air at 110-120°C (patented system). Also during this phase, PLC-operated solenoid valves control the injection times. The perfect cleaning and decontamination of the containers is guaranteed by a filtered-air laminar-flow cabinet using HEPA filters. The area in which sterilization takes place is kept in a state of slight overpressure, allowing the air to flow towards the outside, thereby avoiding possible sources of contamination. The containers reach a level of decontamination equal to log 4 or even higher. In order to ensure that every bottle is actually sanitized, Promec designed and patented a system for controlling the flow efficiency. Linked to each spraying valve, it checks the correct operation of all nozzles and the efficacy of the cleansing solution injected in each container treated.