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Pseudomonas
Published in Dongyou Liu, Handbook of Foodborne Diseases, 2018
Rajasekharan Sharika, Krishnaswamy Balamurugan
Pseudomonas spp. are a major contributor of food spoilage involving fruits, vegetables, grains, milk, meat, poultry, eggs, and fish as well as processed food made from these raw materials.77–79 These psychrotrophic bacteria are acquired either during the time of harvest or during processing and handling from the environment. The shelf life of a food source is determined based on the growth of the microbial flora and time duration it takes to spoil the food. Storage of food items at low temperature is one of the most common and reliable methods to slow down food spoilage, although certain species of Pseudomonas thrive in such conditions and tend to multiply, causing off- flavor of food and slime formation on food.80,81Pseudomonas species are known to produce a number of hydrolytic and catalytic enzymes that can cause the spoilage of food.80,82
Exopolysaccharide Production from Marine Bacteria and Its Applications
Published in Se-Kwon Kim, Marine Biochemistry, 2023
Prashakha J. Shukla, Shivang B. Vhora, Ankita G. Murnal, Unnati B. Yagnik, Maheshwari Patadiya
The deep sea is a major component of our planet’s biosphere and represents 75 % of the total volume of the oceans. These environments are influenced by high pressure, low temperature and low nutrient concentration. Psychrotrophic bacteria possess the capability of growing above 20°C as well as tolerating low temperatures, whereas psychrophilic bacteria prefer to grow in temperatures as up to 20°C (0–20°C; Gounot, 1986). Few other examples of EPS-producing marine microbes include the psychrotolerant strain of Pseudoalteromonas sp. Bsi20310 from the sea ice of Antarctica (Bozal et al., 1997; Ma et al., 2012). Bacillus licheniform is strain B3–15, originating from a shallow marine vent, produced a novel EPSs, which is used as a counteractive agent for immune disorders caused by the herpes virus (Spanò and Arena, 2016), whereas Pseudoalteromonas antarctica strain NF3, isolated from a glacial marine sludge of the South Shetland Island in Antarctica, produced maximum EPSs during its exponential growth phase. Pseudoalteromonas strain SM9913, isolated from deepsea sediment from the Bohai Gulf, Yellow Sea, China, synthesized EPSs having linear arrangement of α (1 → 6) linkage of glucose with a high degree of acetylation, showing flocculation behavior and high biosorption capacity. EPSs produced by this strain are inversely proportional to the temperature fluctuation. Pseudoalteromonas strains CAM025 and CAM036, isolated from the Southern Ocean, have sulfate and uronic acids as galacturonic acid along with acetyl groups. In addition, strain CAM036 has been reported to possess a succinyl group. These features confer a polyanioinic nature to EPSs in a marine environment as at an alkaline pH, the acidic group on EPSs are ionized. This property makes EPSs bind cations, such as dissolved metals (Mancuso Nichols et al., 2004).
Dry eye disease: an (in)convenient truth
Published in Clinical and Experimental Optometry, 2022
Azadeh Tavakoli, Judith Louise Flanagan
In 2003, a ‘cold chain’ hypothesis was proposed to explain the increasing incidence of inflammatory bowel disease.70 This theory suggests a connection in the parallel rising incidence of Crohn’s disease and uptake of domestic refrigeration, another symbol of modern convenience. Hugot and colleagues70 outline the prevalence of Crohn’s disease roughly matching the rise in modern Western lifestyles; 1940s in the USA, 1950s in Sweden, the 1960s in the UK, and later in southern Europe.71 The cold chain hypothesis suggests that modern food production requires a ‘chain of refrigeration’ from producer to consumer (‘of the 520 kg of food eaten every year per person in France, 320 kg are, at some time, conserved at a low temperature’70) which enables overgrowth of pathogenic psychrotrophic bacteria that can flourish between −1°C and 10 °C.
Multispecies biofilm formation by the contaminating microbiota in raw milk
Published in Biofouling, 2019
G. S. Oliveira, D. R. G. Lopes, C. Andre, C. C. Silva, F. Baglinière, M. C. D. Vanetti
The average psychrotrophic count was 4.8 × 104 CFU ml−1 in the samples of fresh milk (Figure 1A), while in the bulk milk samples, the average was 4.5 x 106 CFU ml−1 (Figure 1B). The contamination of raw milk by psychrotrophic aerobic bacteria is a major concern in the dairy industry since many dairy products are stored and distributed at temperatures suitable for the growth of these organisms (Samaržija et al. 2012; Machado et al. 2017). Yuan et al. (2018) observed that a wide range of psychrotrophic bacteria isolated from raw milk showed a biofilm formation capacity at 7 °C, so this group of bacteria is of great concern in the dairy industry.