Impact of Edible Coating and Different Packaging Treatments on Microbial Quality of Paneer

Milk and milk products form an essential component of the human diet and no other single natural food meets the nutritional requirements better than milk. There are various dairy products like cheese, butter, ghee, paneer, khoa, curd; malai etc., among these paneer is an important indigenous dairy product. The shelf life of panner is only 1 day at room temperature and 6 days at 10°C [1]. Many techniques have been studied in order to overcome these problems and extend the shelf life of fresh produce, for example, low temperature and high relative humidity, controlled and modified atmosphere packaging, etc. Edible film and coating enhances the quality of food products, protecting them from physical, chemical and microbiological deterioration [2]. Edible coating can act as moisture and gas barriers, control microbial growth, preserve the color, texture and moisture of the product, and can effectively extend the shelf life of the product.


Introduction
Milk and milk products form an essential component of the human diet and no other single natural food meets the nutritional requirements better than milk. There are various dairy products like cheese, butter, ghee, paneer, khoa, curd; malai etc., among these paneer is an important indigenous dairy product. The shelf life of panner is only 1 day at room temperature and 6 days at 10°C [1]. Many techniques have been studied in order to overcome these problems and extend the shelf life of fresh produce, for example, low temperature and high relative humidity, controlled and modified atmosphere packaging, etc. Edible film and coating enhances the quality of food products, protecting them from physical, chemical and microbiological deterioration [2]. Edible coating can act as moisture and gas barriers, control microbial growth, preserve the color, texture and moisture of the product, and can effectively extend the shelf life of the product.
The microbiological quality of paneer depends on the microbiological quality of milk, and the hygiene exercised during manufacture of paneer and its subsequent handling, packaging and storage. Microorganisms such as coliforms, yeasts and moulds that might be present in raw milk get destroyed completely, when milk is heated at 82°C for 5 min. But these microbes may contaminate the product through a number of sources like air, water, equipment, knife, muslin cloth and persons handling the products [3]. These microbes can cause proteolytic and lipolytic changes, discoloration and other defects in the product [4]. According to Sachdeva [5], quality of paneer deteriorates due to the growth of organisms on the surface of paneer during storage. The total counts as well as yeast and mould counts increased during storage of paneer up to 10 days at 5ºC. Gupta [6], Thakral [7] and Parashar [8] reported about the increasing trend of the total viable count of paneer treated with 2% potassium sorbate.
The objective of present investigation is to evaluate the effect of edible coating and different packaging treatments on microbial quality of paneer and help to increase the shelf life of paneer.

Materials and Methods
Buffalo milk, whey protein concentrate, citric acid and water were used in the investigation.

Paneer preparation
Paneer was prepared as per the procedure outlined by Sachdeva [5]. Composite edible coating prepared by using whey protein concentrate and applied on the cubes of paneer. Edible coating acted as moisture and gas barrier, control microbial growth, preserve the color, texture and moisture of the product and effectively extend the shelf life of the product.
Then edible coated paneer cubes was packed into polypropylene, LDPE, and laminates and stored at temperatures 5 ± 1°C, 30 ± 1°C and ambient conditions. The stored paneer samples were tested periodically.

Analytical procedures
Total Viable count and Yeast and Mould Count were determined by using APHA [9] method.

Statistical analysis
Statistical analysis was performed using 3 Factorial completely randomized design (CRD). The experimental data were analyzed using the statistical methods of Snedecor and Cochran [10].

Impact of Edible Coating and Different Packaging Treatments on Microbial Quality of Paneer
Archana G. Lamdande 1 *, Shyam R. Garud 2 and Anil Kumar 1

Results and Discussion
The effect of coating and packaging materials on microbiological characteristics of paneer during storage without vacuum were recorded below.

Total Viable Count (TVC)
Packaging material had significant effect (P ≤ 0.05), whereas coating and temperature and their interactive effect were found significant (P ≤ 0.01) on total viable count of the product during storage ( Table 1).
The initial total plate count of control fresh paneer (P 1 ) was 3.0 × 10 2 cfu/g which increased at the end of 6 th day up to 4.6 × 10 3 cfu/g. Laminate packed uncoated paneer samples had microbial count 1.08 × 10 4 cfu/g on 28 th day of storage. Whereas, coated samples of paneer packed in polypropylene had microbial count 2.15 × 10 3 cfu/g on 36 th day of storage and LDPE and laminates packed coated paneer had microbial count 1.6 × 10 3 and 2.75 × 10 3 cfu/g on 40 th day of storage at 5 ± 1°C (Table 3).  The coated samples of paneer packed in polypropylene, LDPE and laminates had total plate count 5.95 × 10 3 , 5.15 × 10 3 and 6.55 × 10 3 cfu/g on 12 th day of storage under ambient conditions (Table 4).

Yeast and Moulds counts (Y & M counts)
Coating of paneer, packaging material and temperature and their interaction had significant effect (P ≤ 0.01) on Y & M counts of the product during storage at 30 ± 1ºC (Tables 5 and 6). The uncoated samples packed in polypropylene, LDPE and laminates had Y & M counts 1.25 × 10 3 , 1.85 × 10 3 and 2.05 × 10 3 cfu/g on 2 nd day. Coated paneer samples packed in polypropylene, LDPE and laminates had Y & M counts 1.45 × 10 3 , 1.95 × 10 3 and 2.15 × 10 3 cfu/g on 12 th day of storage.