High-temperature, short-time pasteurized milk

The waste milk in dairy wastewaters mostly comes from start-up and shut-down operations performed in the high-temperature, short-time pasteurization process. This waste is pure milk raw material mixed with water. Another wastewater of the dairy sector originates from equipment and tank-cleaning wastewaters. These waste streams contain waste milk and sanitary cleaners that are the principal waste constituents of dairy wastewater. Over time, milk waste degrades to form corrosive lactic and formic acids. Approximately 90% of a dairy s wastewater load is milk. 

High-temperature short-time pasteurization of milk at 88 degrees Celsius for one second is as effective in killing pathogenic bacteria as conventional pasteurization at 63 degrees Celsius for thirty minutes and is less damt ing to the value of the food. 

Pasteurization may be carried out by batch- or continuous-flow processes. In the batch process, each particle of milk must be heated to at least 63°C and held continuously at this temperature for at least 30 min. In the continuous process, milk is heated to at least 72°C for at least 15 s ia what is known as high temperature—short time (HTST) pasteurization, the primary method used for fluid milk. For milk products having a fat content above that of milk or that contain added sweeteners, 66°C is requited for the batch process and 75°C for the HTST process. For either method, foUowiag pasteurization the product should be cooled quickly to <7.2° C. Time—temperature relationships have been estabHshed for other products including ice cream mix, which is heated to 78°C for 15 s, and eggnog, which must be pasteurized at 69°C for 30 min or 80°C for 25 s. 

High-temperature short time (HTST) pasteurization is used in a majority of plants in the United States. HTST pasteurization is conducted at temperatures > 72 °C and holding time > 15 s in the United States (FDA, 2009). Milk may also be pasteurized using ultrahigh temperature (UHT) pasteurization. 

Compatible with protein-rich beverages (e.g., milk-based soy-based) treated with high-temperature short-time (HTST) pasteurization. However, may be issues with flocculation, thickening, or sedimentation due to Ca-protein interactions when subjected to ultra-high temperature (UHT) heat treatment... 

Edmondson et al (1971), who studied the enrichment of whole milk with iron, found that ferrous compounds normally caused a definite oxidized flavor when added before pasteurization. Aeration before addition of the iron reduced the off-flavor. The authors recommended the addition of ferric ammonium citrate followed by pasteurization at 81 °C. Kurtz et al. (1973) reported that iron salts can be added in amounts equivalent to 20 mg iron per liter of skim milk with no adverse flavor effects when iron-fortified dry milk is reconstituted to skim milk or used in the preparation of 2% milk. Hegenauer et al. (1979A) reported that emulsification of milk fat prior to fortification greatly reduced lipid peroxidation by all metal complexes. These researchers (Hegenauer et al. 1979B) concluded that chelated iron and copper should be added after homogenization but before pasteurization by a high-temperature-short-time process. 

High-temperature short-time (HTST) treatment (72°C x 15 s) of milk almost completely inactivates the enzyme (Luhtala and Antila, 1968 Andrews et al., 1987 Farkye et al., 1995) so that little if any lipolysis caused by milk lipase occurs in pasteurised milk (Downey, 1974). Somewhat higher temperatures are required for cream pasteurization because of the protective effect of the fat (Nilsson and Willart, 1961 Downey and Andrews, 1966). However, some workers have reported that a more severe heat treatment, [e.g., 79°C x 20 s, (Shipe and Senyk, 1981) or 85°C x 10 s (Driessen, 1987)] is required to inactivate completely milk lipase. 

High-temperature short-time (HTST) pasteurization Process in which milk is heated to 71.6°C for at least 15 s. 

High Frequency of Recombination (Hfr) Strain A strain of bacteria in which the F plasmid is incorporated into the bacterial chromosome. High-Temperature Short-Time (HTST) Pasteurization Process in which milk is heated to 71.6°C for at least 15 seconds. Known also as Flash Pasteurization. 

Fig. 10.15. Heating of milk. 1-3 Pasteurization 1 high temperature treatment, 2 short time and 3 long time heat treatment 4 and 5 UHT treatment 4 indirect and 5 direct 6 sterilization, a Killing pathogenic microorganisms Tubercle bacilli as labelling organism), b c inactivation of alkaline/acid phosphatase, d, d2, d denat-uration (5, 40, 100%) of whey proteins, e casein heat coagulation,/ start of milk browning...

A term used to describe microorganisms (bacteria) that are heat tolerant. Thermodurics survive for short periods of time at high temperatures, but they do not grow at high temperatures. For example, thermodurics survive pasteurization of milk for short periods of time. 

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