National Dairy Research Institute

About: National Dairy Research Institute is a facility organization based out in Karnāl, Himachal Pradesh, India. It is known for research contribution in the topics: Population & Sperm. The organization has 3228 authors who have published 3524 publications receiving 51151 citations. The organization is also known as: Imperial Institute of Animal Husbandry and Dairying & Imperial Dairy Institute.

Effect of Modified Atmosphere Packaging (MAP) and Storage on the Chemical Quality of Paneer

Abstract: Traditional food packaging protects food from external contamination, oxygen, water vapour and light. However, newer packaging technologies such as Modified Atmosphere Packaging (MAP) do more than just provide protection from outside influences. The study was conducted to increase the shelf life of paneer by using MAP technique. The paneer samples were packaged in high barrier bags (LLD/BA/Nylon-6/BA/LDPE) under different atmospheres: atmospheric air (atm1), vacuum (atm2), 100% CO2 (atm3) and 100% N2 (atm4). A headspace to product ratio of 1-2 litres gas / kg product was initially set in the MAP system and stored the samples at 7±1oC. Periodically, paneer samples were evaluated for changes in chemical characteristics. The analysis of variance of the data revealed that the MAP had significant influence on moisture, titratable acidity, pH, free fatty acids, and tyrosine content of the paneer samples during storage.

Heat Stress and Hormones

Abstract: Activation of the hypothalamic–pituitary–adrenal axis and the consequent increase in plasma glucocorticoid concentrations are two of the most important responses of the animals to heat stress. The short- and long-term environmental heat affects endocrine glands and in turn release of hormones, namely, thyroxine, cortisol, growth hormone and catecholamines. Some of them result in initial increase due to acute stressors and a decline in plasma levels after prolonged exposure to stressors has been observed. The relationship of amounts in plasma of these hormones to milk production appears to be related directly for cortisol, growth hormone and prolactin with an inverse relationship with thyroxine. Epinephrine and norepinephrine are elevated with prolonged environmental heat stress. Hormones in plasma are important as potential indicators of the physiological status of a cow and reflect the physiological compensations a cow undergoes at various stages of lactation and exposure to heat stress. The plasma thyroxine (T4) and triiodothyronine (T3) levels have been observed to decline under heat stress as compared to thermoneutral conditions. The decline in thyroid hormones along with decreased plasma growth hormone (GH) level has a synergistic effect to reduce heat production. A reduced secretion of GH is required for survival of the homeotherm during heat stress. The concentration of insulin-like growth factor-1 (IGF-1) has been observed to decrease during the summer months. Aldosterone concentration declines due to a fall in serum K levels and increased excretion in sweat during heat stress. Heat stress has a detrimental effect on animal reproduction partly by disrupting the normal release of gonadotrophin-releasing hormone from the hypothalamus and luteinising hormone (LH) and follicle-stimulating hormone from the anterior pituitary gland. Heat stress reduces the degree of dominance of the selected follicle as reduced steroidogenic capacity of its theca and granulosa cells and a fall in blood oestradiol concentrations. Plasma progesterone levels may be increased or decreased depending on whether the heat stress is acute or chronic and also on the metabolic state of the animal. Insufficient progesterone secretion by the corpus luteum during summer is a probable reason of low fertility in cattle and buffalo during summer months in tropical climates.

Exploring specific primers targeted against different genes for a multiplex PCR for detection of Listeria monocytogenes.

Abstract: The efficacy of six different sets of primers targeted against 16S rRNA and virulence genes such as ‘iap’, ‘hly’ and ‘prf’ was evaluated in separate PCR assays. The primer pairs targeted against 16S rRNA resulted into amplification of 1.2 kb PCR product. However, sets of primers targeted against different regions of ‘iap’ produced 371 and 660 bp PCR products, respectively. The primer pair targeted against ‘prf’ gene could produce 508 bp product. Three primer pairs targeted against different regions of ‘hly’, i.e., ‘hly’, ‘hly A’ and ‘hly K9’ were able to amplify 713, 276 and 384 bp products, respectively. The PCR conditions were also optimized in respect of two internal sets of primers falling within ‘iap’ and ‘hly’ genes that amplified 119 and 188 bp products to verify the PCR results obtained with respective external sets of primers. Three different combinations involving four sets of primers based on 16S rRNA, ‘iap’, ‘hly’ and ‘prf’ were explored in respective multiplex PCR assays in order to select a suitable combination. Combination 1 and 3 worked successfully as revealed by amplification of all the four bands of expected sizes on agarose gel. However, while optimizing the different parameters for developing a functional multiplex PCR, it was observed that in both these combinations, only two of the amplified products, i.e., 1.2 kb and 713 bp could be invariably detected. Hence, these two primers were combined in the multiplex PCR and the conditions were optimized for application in dairy foods for detection of Listeria monocytogenes.