The Indian dairy industry also faces the same global problems. But one issue that is of immediate importance is the shortage of clean water. India depends on water from fickle monsoons and from the stores in rapidly depleting aquifers. They compete for this limited source with the farmers and the needs of a growing population. Programmes to save water take on more importance with economic growth and urban development.
Ecolab, a global provider of food safety solutions, has recently launched programmes that promote saving of time, energy, water and chemicals. Such programmes assist dairy companies to achieve their sustainability goals. They also increase their profits.
Difficult areas to clean
Some dairy processes use high temperatures in equipment such as plate heat exchanges, holding tubes, evaporators and dryers, to process milk and eliminate microorganisms that cause disease and food spoilage. The high temperatures cause the formation of residues that are difficult to clean with conventional CIP programmes with alkali and acid. Attempts to remove such residues usually take a long time and use high temperatures and large amounts of chemicals. Often, such programmes require repeated use of alkali or acid. In spite of this, the residues on some equipment are still not being completely cleaned by their current programmes. The consequences are longer delays before line start production and the threat posed by the increase risk of food poisoning episodes that could endanger the survival of companies.
Special programmes are now available to resolve these issues. The Exelerate HS-I programme is a patented programme developed to remove difficult soils on heated surfaces. It is popular in large dairy markets in the US, Australia and New Zealand. In Asia-Pacific, 14 countries including India use this programme. This programme uses special chemical reactions to provide extra mechanical effects, the equivalent of scrubbing the soiled surface to remove the soil. In so doing, the surfaces are completely clean more quickly (see Figs.1 & 2a, 2b) and at lower cleaning temperatures and with less water.
Fig 2b. After HSi program
Fig 2a. After conventional CIP program
A …...B Fig 1. Plate Heat Exchanger after alkali cleaning (A) and after HSi cleaning program (B)
Benefits
The benefit is that the surface can now be consistently, completely cleaned (100%), ensuring that the cleaning results are repeatable and the clean equipment produces consistently excellent, quality product. The need for repeated QC checks is eliminated.
The other valuable benefit is that the time that is saved can now be utilised for extra production especially if the soiled equipment and the ineffective previous cleaning programme was the cause of delays in the start up of the line. The bottleneck has been removed. Productivity is increased. Time savings of at least 30-60 minutes are achieved for cleaning evaporators systems that no longer need to be opened after each CIP for inspection and manual re-cleaning. This time is translated into the production of extra milk powder.
Other benefits include energy, water and chemical savings because the cleaning time has been reduced when effective, shorter cleaning times at lower temperatures are used with lower caustic concentration. Another benefit is the postponement of capital expenditure required to add another production line to increase production. A reduction in CIP time of 60 minutes/day translates into a gain of 7 hours per week extra production time.
Low temperature cleaning of raw milk processing area
Dairy producers are looking for programmes to reduce energy consumption without affecting the effectiveness of the cleaning. This pose challenges to cleaning effectively with current cleaning programmes. There are solutions but these solutions currently apply to only areas where processing temperatures are not high such as the raw milk processing areas where the milk tankers bring in fresh milk from farms to be stored and processed and sent onwards for further processing.
Ecolab has developed a patented programme, Advantis LT that cleans the milk tankers, lines, storage tanks and pasteuriser in the raw milk area at low temperatures. It is proving to be a more effective cleaning programme than the current programmes. The programme successfully cleans the equipment at temperatures between 43 and 50o C with two unique products – a base with a catalyst, and an activator. The activator is injected directly into a pipe containing a solution of the base. The resulting mixture is pumped to the object to be cleaned. This cleaning solution effectively cleans at a lower temperature than conventional programmes because of the mechanical effect caused by bubbles formed by the breakdown of the activator. The soil in the equipment is broken down and removed. The base solution can be reused and only the activator needs to be replenished.
The benefits of the programme
a) Savings in energy costs for processing and cleaning raw milk areas by as much as 40-60% of their current steam costs, and about 5-15% of the plant’s total steam cost. These savings are translated into reduced CO2 released from reduce use of fossil fuels to fuel the boiler.
b) Reduced wear from thermal expansion and contraction of the stainless equipment and seals. The lower temperature reduces wear of seals so that they do not have to be changed on a yearly basis.
This programme is used only to clean the raw milk receiving area of milk plants. It is not suitable for cleaning equipment where high temperatures (eg >121oC) are used to process milk. Here the HSi programme is better suited for the equipment. This programme is gaining in popularity in the US and in countries that use expensive fossil fuels to heat cleaning solutions. It is new to the Indian subcontinent.
Cleaning with sulfuric acid-based cleaners at low temperatures
Currently, hot cleaning programmes with a mineral acid (phosphoric or nitric acid based acids) are used to remove the mineral deposit of calcium phosphate that remains after production and cleaning with a hot alkali. Unless it is removed, the minerals serve as traps for more soil and breeding areas for pathogenic and spoilage microorganisms. The recent increase in the price for phosphoric acid and the subsequent increase in demand for nitric acid for cleaning caused the price of nitric acid to increase. Alternative acid cleaners such as sulfuric acid are now being considered for use to remove mineral scale (milk stone).
Sulfuric acid is stronger than phosphoric and nitric acids. Less can be used to deliver equal performance on surfaces soiled with mineral deposits at lower acid concentrations and lower temperatures. But there are fears of its corrosive effects on 304 and 316 grades steel, the most commonly used steels in the region. These fears that the stainless steel will be damaged if sulfuric acid based products are used are largely unfounded. Ecolab has conducted a number of laboratory experiments to demonstrate the effect of the product on corrosion of stainless steel to show that their equipment will not be damaged.
The key requirement is that the acid does not cause corrosion that exceed the corrosion standards set by international bodies (EU and DIN, American Dairy Association 3A sanitary standards) for 316 and 304 steel, or the higher standards set by Ecolab (see below Fig 3 ):
Fig 3. Corrosion standards
The data clearly (Fig 4) indicates that under the most extreme temperature of 82oC and after two weeks), the amount of corrosion caused on SS coupons is less than the external standards (<4 MPY, 10 MPY) and the standards set by Ecolab (<1 MPY). Given these results, give great confidence to users of the product when the product is used at the lower recommended temperatures of 45-50oC. At these lower temperatures, corrosion is likely to be much less than at 82oC.
This programme is popular in the US where most of the plants (>200) that were previously using phosphoric/nitric acid based products from Ecolab are now using this programme to save energy. Plants clean at 40o-50oC, lowering energy (steam) demands by 40-60% of the original hot acid cleaning programme (70-80o C). It has just been introduced into this region.
Fig 4. Corrosion of stainless steel with nitric acid and Envirocid Plus Clear
What lies ahead?
The future is now clearer for all to see. It lies in continuing efforts to drive sustainability programmes throughout the dairy industry. The real benefit in energy, water and chemicals and time savings is the increased plant profitability and the reduced pollution load on the environment. For India, the benefits of saving water are immense. It extends the life of the aquifers and reduces energy usage that is so vital to a country that does not have major supplies of fuel.
