Collaborative Evaluation of a Fluorometric Method for Measuring Alkaline Phosphatase Activity in Cow's, Sheep's, and Goat's Milk

Harding, F.; Garry, Eileen

doi:10.4315/0362-028x-68.5.1047

Cited by 18 publications

(13 citation statements)

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“…Alkaline phosphatase (ALP, EC 3.1.3.1) is an appropriate indicator for the evaluation of pasteurisation or the addition of raw milk to pasteurised milk or milk products Shakeel-Ur-Rehman et al 2003;Harding and Garry 2005; Commission Regulation No 1664 (EC, 2006. Lactoperoxidase (LPO, EC 1.11.1.7) is one of the most heat stable enzymes in bovine milk (Seifu et al 2005).…”

Section: Introductionmentioning

confidence: 99%

A survey of the quality of extended shelf life (ESL) milk in relation to HTST and UHT milk

Lorenzen

Clawin‐Rädecker

Einhoff

et al. 2011

Int J of Dairy Tech

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Thirty milk samples [high-temperature short-time (HTST) milk, extended shelf life (ESL) milk (directly heated, indirectly heated, microfiltered), ultra-high temperature milk] from 17 German dairies were analysed. Total viable counts of directly or indirectly heated ESL milk were significantly lower than those in microfiltered ESL and HTST milk. Evaluation of indigenous enzyme activity revealed sufficient heat treatments in all milk samples. The manufacturing processes were differentiated by estimating furosine and acid soluble whey proteins. Sensory examinations revealed a preference for HTST heated and microfiltered ESL milk. However, a significant discrimination of drinking milk types was not possible. Vitamin losses were not detected, and concentrations of vitamins in different types of milk were comparable.Keywords Drinking milk, Microbiological status, Head load evaluation, Sensory quality, Vitamin status. I N T R O D U C T I O NExtended shelf life (ESL) milk has a shelf life of about 3 weeks under chill chain conditions and fills the gap between high-temperature short-time (HTST)-heated milk, which typically is assigned a shelf life of 10 days and ultra-high temperature (UHT)-heated milk, which can be stored for a few months without cooling (Hoffmann et al. 2006). In Germany, ESL milk has a market share of 20-25%. For comparison, UHT milk has a share of approximately 70%, and HTST milk has a market share of 5-10% (BLE 2008). The term ESL milk as well as the manufacturing process is not legally defined in the European Union. A thermal treatment or combination of heat treatment and membrane filtration are involved in the production of ESL milk. The thermal process requires direct or indirect heating at 123-127°C with a holding time of 1-5 s. Traditional HTST pasteurisation is carried out at 72-75°C for 15-30 s, and UHT milk is heated at a minimum of 135°C for a few seconds (sterilisation value F 0 ‡ 3 min) (Schwermann and Schwenzow 2008a,b;Kaufmann et al. 2009). The combined treatment process for ESL milk includes microfiltration of skim milk through ceramic membranes with an average pore diameter of 0.8-1.4 lm. As a result, a spore reduction of 3-5 log 10 steps is achieved and most other forms of microorganisms are also separated. The so enriched retentate and a specific amount of cream are heated at 123-127°C, homogenised, and mixed with the HTST heated skim milk permeate (Hoffmann et al. 2006;Schwermann and Schwenzow 2008c;Henke 2009).Microbial spoilage of heat treated drinking milk is caused by heat-resistant or recontaminating micro-organisms. The former group is represented by spore forming micro-organisms, mainly Bacillus spp. and Enterococci. The latter group consists of Gram-positive nonspore forming bacteria and Gram-negative bacteria. These organisms gain significance if they are psychrophilic or psychrotrophic and able to multiply at refrigeration temperatures (Blake et al. 1995;Mayr et al. 2004;Kress et al. 2005;Kaufmann and Kulozik 2008).Several parameters are suited for the evaluation of milk...

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Section: Introductionmentioning

confidence: 99%

A survey of the quality of extended shelf life (ESL) milk in relation to HTST and UHT milk

Lorenzen

Clawin‐Rädecker

Einhoff

et al. 2011

Int J of Dairy Tech

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“…Inactivation of AP indicates that pathogens able to proliferate in milk have been killed during heating. The present standard within the EU sets an AP activity limit of 500 mU ⁄ L based on a fluorometric method (Harding and Garry 2005;CEN-European Committee for Standardisation 2006). Other indigenous milk enzymes are useful as time-temperature treatment indicators e.g.…”

Section: Introductionmentioning

confidence: 99%

Instant infusion pasteurisation of bovine milk. II. Effects on indigenous milk enzymes activity and whey protein denaturation

Hammershøj

Hougaard

Vestergaard

et al. 2010

Int J of Dairy Tech

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Direct heat treatment of two milk types, skimmed and nonstandardised full-fat, was performed by instant steam infusion and compared with indirect heating. Infusion conditions were temperatures of 72-120°C combined with holding times of 100-700 ms, and indirect heat conditions were 72°C ⁄ 15 s and 85°C ⁄ 30 s. The activity of indigenous enzymes such as alkaline phosphatase, lactoperoxidase, xanthine oxidase and c-glutamyl transpeptidase was evaluated. Infusion temperature was the main determinant of inactivation. Whey protein denaturation represented by b-lactoglobulin increased significantly with infusion temperature. The nonstandardised milk had a higher denaturation rate than skimmed milk. The effect of instant infusion on pH and milk fat globule size in relation to whey protein denaturation and association is discussed.

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“…As the enzyme alkaline phosphatase is inactivated in temperature ranges slightly higher than these microorganisms, it is used as an indicator for monitoring good pasteurization conditions (Sanders and Sager, 1948;Murthy and Cox, 1988;Holsinger et al, 1997;Stabel, 2003). Other interpretations of elevated ALP activities in finished products include the presence of bacterial ALP, or the biochemical reactivation of the ALP enzyme (Rankin et al, 2010).…”

Section: Introductionmentioning

confidence: 99%

“…Moreover, residual levels of enzyme are related to thermal process and initial enzyme levels. These factors may affect the detection limits for this enzyme ( Harding, 1991, Yoshotomi, 2004Harding and Garry, 2005).…”

Section: Introductionmentioning

confidence: 99%

Application of Scharer's quantitative method for the determination of residual alkaline phosphatase activity in standard Minas

Soares

Fonseca

Leite

et al. 2013

Arq. Bras. Med. Vet. Zootec.

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Milk pasteurization is a critical issue in the dairy industry, and failures in this process can affect final product safety. Scharer's enzymatic method is still traditionally used to verify pasteurization efficiency compliance, and it is based on screening for residual alkaline phosphatase in milk. Although several methods are used to quantify enzymatic activity to assess milk pasteurization efficiency, there is a small amount of published data regarding the use of these methods to quantify alkaline phosphatase in cheese. In this study, the Scharer's modified method was used to determine the levels of residual alkaline phosphatase in standard minas cheese, before and after 20 days of ripening. The cheeses were made using raw or pasteurized milk with the addition of different concentrations of raw milk (0; 0.05%; 0.10%; 0.20%; and 0.50%). In the fresh cheese samples, the method showed a sensitivity of only 0.50% with the addition of raw milk to the pasteurized milk used to make cheese. In addition, levels of up 0.20% of raw milk in pasteurized milk, the concentrations of phenol was inferior to 1g phenol/g of dairy product which is the preconized indicator value for adequate pasteurization. (0, 0,05%, 0,10%, 0,20% e 0,50%

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Collaborative Evaluation of a Fluorometric Method for Measuring Alkaline Phosphatase Activity in Cow's, Sheep's, and Goat's Milk

Cited by 18 publications

References 3 publications

A survey of the quality of extended shelf life (ESL) milk in relation to HTST and UHT milk

A survey of the quality of extended shelf life (ESL) milk in relation to HTST and UHT milk

Instant infusion pasteurisation of bovine milk. II. Effects on indigenous milk enzymes activity and whey protein denaturation

Application of Scharer's quantitative method for the determination of residual alkaline phosphatase activity in standard Minas

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