Cleaning of bottles and cses in meat production
In several food industries, bottles and cases are used when packaging the final products. Bottles and cases are in direct contact with the food, therefore they must be sufficiently cleaned before being used. The cleaning process removes possible food residues, dirt and odours from the packaging containers, while it minimises their microbiological load, according to hygiene and health regulations. The cleaning takes place in relatively high temperatures using hot water. The cleaning of bottles and cases consumes large quantities of water and produces a high amount of waste water but with a low organic load.
2. FIELD OF APPLICATION
Bottles and cases are used widely in breweries, dairy, fruit/vegetable, oil, wine and meat industry (BAT in the Food, Drink and Milk Industries, June 2005).
3. DESCRIPTION OF TECHNIQUES, METHODS AND EQUIPMENT
- General bottle and case washing system:
- Description of the bottle cleaning process:
- The process requires large quantities of water. Water is usually heated up by steam until 90°C.
The table below shows the washing parameters for glass and plastic bottles:
- The basic bottle rinsing process is shown below:
- A more detailed description of the bottle cleaning process is shown below:
- Temperature profile of the cleaning process:
4. COMPETITIVE TECHNOLOGIES AND ENERGY SAVING POTENTIALS
- a) Changes in the process
- Multistage bottle cleaning: (BAT in the Food, Drink and Milk Industries, June 2005)
- The multistage bottle cleaning is presented below:
- The individual zones of the multistage bottle cleaning process are the following: 1)soak, 2)caustic bath, 3)1st zone of hot water tank, 4)2nd zone of hot water tank, 5)cold water tank, 6)fresh water tank.
- This cleaning process, which takes place primarily in the soaking zone and the caustic bath, results in clean germ bottles. The interaction of chemical, thermal and mechanical effects ensures that the bottles are cleaned within a certain time.
- Water consumption varies, depending on the bottles and their amount of dirt. Apart from the high water consumption, other disadvantages of the conventional bottle cleaning machines were, e.g. scale formation in the hot water zones and alkali entrainment; the need for expensive complexing agents and disinfectants and the fact that these chemicals can get into the waste water. These are eliminated with this multistage combination process. Even with a 51% reduction in fresh water input, the return of the cooled water still ensures reliable cooling of the bottles. This method is considered economically viable only in cases where a water saving of 200ml per bottle cleaned is needed.
- Ultrasonic cleaning: (?)
- Ultrasonic cleaning has been used in different applications, including crate cleaning in the food industry. Ultrasonic cleaning is particularly effective in the removal of biological contamination because the cleaning action is accomplished through jets induced by cavitational collapse on and near surfaces. These jets are easily capable of dislodging bacteria that may be adhering to the surfaces. The particular advantage of ultrasonic cleaning is that it can reach crevices that are not easily reached by conventional cleaning methods. For this reason, such cleaning is used for a range of items like large crates used for food packaging.
- Heat, power, frequency, detergent type and time affect the cleaning process. Ultrasonic cleaning is fast and consistent, while lower chemical concentrations and temperatures are used comparing to other conventional cleaning technologies.
- Nowadays ultrasonic cleaning is not an expensive cleaning alternative. It is estimated to be the lowest cost cleaning method comparing to energy consuming water spraying and mechanical agitation systems.
- Ozone cleaning: (Galitsky et al. BEST Winery Guidebook: Benchmarking and Energy and Water Savings Tool for the Wine Industry, Lawrence Berkeley National Laboratory 2005, publication number LBNL 3184)
- Ozone cleaning is an emerging technology that can be applied to wineries. Barrel cleaning consumes around 1.6 gallons of warm water per barrel. Moving to an ozone cleaning system eliminates the use of hot water for barrel cleaning, saving both energy and water.
- Ozone cleaning can eliminate the need for hot water use for barrel cleaning, reducing water use by 50%. Galitsky et al. (2005) estimate typical water use for barrel cleaning at 1.6 gallon/case. Various suppliers provide (mobile) ozone generators. Ozone is a toxic gas. It is made onsite and on demand by a generator. This eliminates the risks of storage. Personnel using the ozone cleaning process should be properly trained.
- Minimization of bottle use: (Joanneum Research)
- Maximizing the use of metal cans in food industry, i.e. in breweries, results in a reduction in the number of bottles needed. Therefore, the energy consumption in bottle cleaning is reduced.
- b) Changes in the energy distribution system
- Waste water recycling: (BAT in the Food, Drink and Milk Industries, June 2005)
- The energy efficiency of the bottle, can or other container cleaning system can be improved by the re-use of waste water streams as energy carriers in heat exchangers. Waste water produced during the bottle cleaning process or during other production stages, e.g. wort cooling, can be recycled to reduce the energy consumption.
- In the first case, a typical solution for reduced energy consumption is to re-use the final rinse-water for the pre-rinse or other stages when cleaning containers, as it is shown below:
- In the second case, waste water produced in different production stages, e.g. wort cooling in a brewery, can be recycled and used directly in the bottle cleaning process.
- In all cases, the consumption of fresh water supply for heating or cooling can be reduced.
- c) Changes in the heat supply system
No information is available.