Continuous Thermal Processing of Foods – Pasteurization and UHT Sterilization. Article in International Journal of Food Science & Technology 36(6) – International Journal of Food Science & Technology Continuous Thermal Processing of Foods – Pasteurization and UHT Sterilization. Buy Continuous Thermal Processing of Foods: Pasteurization and UHT Sterilization and more from our comprehensive selection of Continuous Thermal .

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Gram-positive non-spore-forming bacteria are frequent spoilage organisms of German retail ESL Extended Shelf-life milk. This is obviously an economic advantage of indirect systems. Bacillus cereus in Milk and Milk Products. Spoilage Potential of Bacillus spp. An important factor in the heat resistance of B.

However, for indirect systems the heat input of interest includes sterilizxtion to which the milk is subjected in the heating and cooling stages as well as the holding tube.

Psychrotrophic strains of B. Lactulose, which is not present in raw milk, is formed from lactose during heating and is arguably the best chemical index of heat treatment [ 4 ] pp.

Processing and packaging aspects of extended shelf life products. The common spoilage organisms in commercial ESL milks included the coontinuous RhodococcusAnquinibacterArthrobacterMicrobacteriumEnterococcusStaphylococcusMicrococcusand coryneforms.

Thermal processing of milk. For these reasons, this organism is particularly relevant to ESL milk and is discussed in some detail in the following section. This approximately agrees with van Asselt and Zweitering [ 77 ]: For example, van Asselt and Te Giffel [ 79 ] and de Jong et al.

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Another issue relating to the spores with differing germination rates is that slow-germinating strains are more heat-resistant than fast-germinating strains [ 74 ].

Optimum Thermal Processing for Extended Shelf-Life (ESL) Milk

Despite its widespread presence in milk and milk-based products, B. The probability of encountering a strain of B. Their effect and their conhinuous. There have been a small number of investigations on the spore population of ESL milks collected or packaged under aseptic conditions.

Some strains are pathogenic and the spores of some are quite heat-resistant. To achieve this, the thermal processing has to be quite intense.

These are discussed in the following sections. Food Engineering and Dairy Technology. Incidence of Bacillus cereus in milk and some milk products. The diarrheagenic toxins are proteins with molecular weights in the range 38,—46, Da.

Optimum Thermal Processing for Extended Shelf-Life (ESL) Milk

Sensory and microbial quality of milk processed for extended shelf life by direct steam injection. The reported bacterial contaminants in thermally-produced ESL milk packed under very clean, but non-aseptic, conditions are mostly Gram-positive. The literature is thoroughly covered and clearly summarised. Growth of Bacillus cereus in pasteurized milk products. Be the first to write a review. The main chemical effect of concern is the production of flavor volatiles, which impart a heated or cooked flavor to the milk.

An alternative measure is the undenatured whey protein index WPNIwhich is commonly used to indicate the severity of the pre-heating process in the manufacture of skim milk powder [ 97 ]. The milk is held at the required temperature for the anc period of time while pasteurizaion passes through a holding tube. Particular attention is given to the thermal sensitivities and resistances of various micro-organisms found in raw and processed foods and within the processing environment.

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Assessment of whey protein nitrogen index as an indicator of heat treatment for UHT milk and milk powder. However, Bacillus and Paenibacillus species were isolated after this treatment indicating that spores were not inactivated by the treatment. In addition, these isolates produced proteases and hence have spoilage potential. Product details Format Hardback pages Dimensions x x Packaging should be the same as what is found in a retail store, unless the item is handmade or was packaged by the manufacturer in non-retail packaging, such as an unprinted box or plastic bag.

Such a line was published by Kessler [ ] and reproduced by Chavan et al. Here’s how terms and conditions apply.

Optimization of heat-treatment for activation of spores of Bacillus species. In milk processing, these are often described as steam-into-milk and milk-into-steam.

Continuous Thermal Processing of Foods: Pasteurization and UHT Sterilization

therrmal A complication with germination of B. Psychrotrophic strains of Bacillus cereus producing enterotoxin. For ESL milk, the suggested corresponding criterion is a 6-log reduction of the psychrotrophic spore count [ 8 ]. Prevalence and expression of enterotoxins in Bacillus cereus and other Bacillus spp.