Describe post harvest processing of cereals and pasteurization of milk in brief.

The post harvesting:-Post Harvest Handling may refer to the phase of crop production that occurs right after harvest and includes cooling, cleaning, sorting, and packing. The majority of fresh fruits, vegetables, and root crops are perishable by nature.

The pasteurization of milk is:-Pasteurization is the process of heating milk (or milk products) to a specific temperature for a predetermined period of time without recontamination. How heat-resistant the bacteria that cause spoilage are frequently determines the target pasteurisation programme temperature.

The pasteurization of milk is :-

Describe post harvest processing of cereals and pasteurization of milk in brief.-To destroy germs and lengthen the shelf life of various packaged and unpackaged items, pasteurisation of milk utilises moderate heat, frequently less than 100 °C (212 °F) (such as milk and fruit juice).

There is an urgent demand for rapid processes that are pertinent to process control to monitor food quality and safety.

By removing or inactivating organisms that lead to food deterioration, including vegetative bacteria but excluding bacterial spores, a technique safeguards food.

Louis Pasteur, a French scientist who demonstrated in the 1880s that heating would leave harmful bacteria in wine dormant, is credited with inventing the process.

In order to achieve food preservation and safety, pasteurisation is currently widely used in the dairy industry and other food processing industries.

Steps of pasteurization:-

Milk chilling:-

Even though pasteurisation is not a component of it, cooling is a necessary step when working with large amounts of milk. When temperatures rise above ambient, milk leaves the cow's udder and promotes rapid bacterial growth, hastening degradation. The growth and metabolism of bacteria are stopped when items are stored between 2 and 5 degrees Celsius. Storing at low temperature offers a suitable alternative before total pasteurisation begins.

Pre-heating (regeneration) and Standardization Stage:-

Before being heated to about 40 °C, the chilled milk is bulked to make it simpler to separate the butterfat during standardisation. Regenerative heating is used in the system, which heats up the incoming cold milk using the heat from the milk that has already been pasteurised. In a countercurrent flow, the chilled milk cools the pasteurised milk. The production of a product with a consistently high butterfat content is the aim of standardisation.

Also Read:-

Clarification stage:-

The finished work must be completely free of all extraneous content.

Metal tube filters are used to strain milk to get rid of big solid particles.

A centrifugal clarifier is used to properly clean milk of all impurities (different from the one used for standardization).

Processing can go on while one filter is being cleaned because the filters are frequently installed as parallel twins.

Regularly cleaning the filters will help to avoid the growth of bacteria (every 2 to 10 operating hours, depending on the level of filth).

Standardization stage:-

Standardizing milk fat is essential if you want to develop a product for the market that is of consistently excellent quality. Different consumers favour diverse products. Some customers just want to consume skim milk, while others want low-fat milk. While some people exclusively drink homogenised milk, others prefer high-fat milk. To ensure that each client is taken care of, normalisation is necessary. You can distinguish between the butterfat required to manufacture cream and other fat-based products like ghee and butter thanks to the standardising procedure once more.

Homogenization stage:-

Milk fat globules are physically broken down into tiny droplets during homogenization to prevent cream separation. They do not rise in a milk column because reducing the size of the fat droplets simultaneously increases their density in the milk. A milk homogenizer running at between 100 and 170 bars separates all of the fat globules into tiny droplets, increasing the milk's level of fat integration. Consequently, the milk fat is still distributed uniformly throughout the milk.

Heating section:-

It raises the temperature of milk from about 60 °C to the required 72 °C, which is required to destroy Clostridium botulinum spores. The steam and milk undergo a counter-current heat exchange across the PHE plates. At the end of the section, a temperature sensor controls the flow diversion valve. Milk that is not heated to the proper temperature is returned to the heating area.

Holding section

After heating, milk is poured into holding tubes that have been lengthened in accordance with the milk flow rate to ensure that the milk remains in the tubes for at least 16 seconds. At the ends of the tubes, all the milk must maintain the required pasteurisation temperatures. If there is a breach, a sensor will activate a flow-diverting valve, sending the milk back to the heating area to be heated to the proper temperature. The milk flows back to the regeneration section after reaching the right temperatures at the end of the holding tubes, where it is chilled to about 30 °C while being heated to warm the incoming cold milk.

Cooling/chilling section

After undergoing regenerative cooling, pasteurised milk travels to the PHE's cooling section, where chilled water and PHE coolant lower the milk's temperature to 4 °C.The cooled milk is taken and pumped to the cold room for storage by the aseptic packaging machinery.

Describe post harvest processing of cereals and pasteurization of milk in brief.