Alkaline phosphatase activity in pasteurized milk: A quantitative comparison of Fluorophos and colourimetric procedures

Payne, Clare; Wilbey, R. A.

doi:10.1111/j.1471-0307.2009.00503.x

Cited by 19 publications

(14 citation statements)

References 13 publications

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“…The reductions in the levels of ALP after microwave and conventional heat treatments are reported in Table (percentage reduction). Conventional heat treatments (LTLT, HTST, and UHT) were shown to inactivate ALP to levels (99.9%, ≤ 350 mU/ml) being accepted by current American and EU legislation (Payne & Wilbey, ). Microwave treatments 2, 6, 10, and 12 enabled the reduction (99.9%) of ALP to less than 350 mU/ml.…”

Section: Resultsmentioning

confidence: 99%

Effects of microwave processing conditions on microbial safety and antimicrobial proteins in bovine milk

Thum

Ozturk

McNabb

et al. 2019

J Food Process Preserv

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The simultaneous effects of microwave processing variables affecting the microbial quality and preservation of milk bioactive proteins were evaluated. Response surface methodology was used to investigate the individual and combined effects of ramp time (2.9–5.5 min), holding time (6.6–23.4 s), and final temperature (60–80°C) on the inactivation of two surrogates (Staphylococcus aureus and Escherichia coli) added to the milk and on the preservation of the main antimicrobial proteins present in milk (lysozyme, lactoferrin, lactoperoxidase, xanthine oxidase, and immunoglobulin G). Experimental conditions resulting in 5 log reduction of E.coli and S. aureus (75°C, ramp time of 4.10 min, and holding time of 20 s) were replicated in quintuplicate for validation of the observed effects. At this experimental condition, more than 95% of the naturally present antimicrobial proteins were inactivated. The inactivation of antimicrobial proteins observed in this study was similar to the ones observed for ultra‐high temperature milk. Practical applications The current study demonstrates that microwave heating conditions leading to microbial safety (5 log reduction of surrogates) result in significant inactivation of bovine milk antimicrobial proteins (>95%), being similar to the ones observed for ultra‐high temperature milk.

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Section: Resultsmentioning

confidence: 99%

Effects of microwave processing conditions on microbial safety and antimicrobial proteins in bovine milk

Thum

Ozturk

McNabb

et al. 2019

J Food Process Preserv

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“…Dairy Products Hygiene Regulations 1995). Improved fluorometric techniques facilitate detection of ALP activity at much lower levels, corresponding with ∼0.003% raw milk in sterilized milk, for example, ( 8 ) and therefore provide opportunities for a range of versatile actions within the bounds set on product safety.…”

Section: Modelling S Aureus In the Processed Milk Chainmentioning

confidence: 99%

“…Payne and Wilbey ( 8 ) provide accurate measurements, using a fluorometric method, for the thermal inactivation of bovine ALP within a pilot plant pasteurization system. The data indicate a reference value D ALP (72) = 3.85 s, for the decimal reduction time of ALP at 72 C, and a fixed scale factor z = 7.54 C. Measurement errors are very small but the D ‐value must be corrected for equipment effects, such as the thermal efficiency and the heating and cooling phases, which include larger uncertainties.…”

Section: Modelling S Aureus In the Processed Milk Chainmentioning

confidence: 99%

“…Recent developments in dairy test procedures, particularly the increased accuracy of a proprietary fluorometric technique for measuring the activity of alkaline phosphatase (ALP), point to new opportunities for improved controls and innovative diagnostics in pasteurized milk production. Colourimetric ALP tests have routinely and reliably been used to confirm the effectiveness of heat treatments applied to milk but several authors ( 5‐8 ) have suggested that the increased sensitivity of fluorometric ALP tests can support improved decision making and could lead to rapid considerations of the cause of alerts or failures with associated benefits in management and intervention.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

A Risk Assessment Model for Enterotoxigenic Staphylococcus aureus in Pasteurized Milk: A Potential Route to Source‐Level Inference

Barker¹,

Goméz-Tomé²

2011

Risk Analysis

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This article describes a probabilistic model that quantifies hazards that arise from Staphylococcus aureus in milk that is sold as pasteurized in the United Kingdom. The model is centered on coupled dynamics for S. aureus populations, staphylococcal enterotoxins, and the concentration of alkaline phosphatase throughout the milk chain. The chain includes farm collection and storage of pooled milk, further pooling for off-farm processing, high temperature short time thermal processing, and possible postprocess contamination. The model is implemented as a Bayesian belief network. The results indicate that milk sold as pasteurized is relatively safe with respect to the hazards associated with S. aureus and that most risk is associated with small scale on-farm processing. An additional analysis of likelihood ratios shows that alkaline phosphatase concentrations in filler tank milk are a good indicator of potential hazards and that these concentrations, in conjunction with other measurements, can be used effectively to discriminate over possible failure modes. The ability to discriminate over potential failure modes can support preemptive actions, such as maintenance or hygiene, which assist with milk chain management and, over extended periods, accumulate to drive improved safety, efficiency, and security.

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“…Colorimetric assays and the phenol measurement method for alkaline phosphatase to indicate pasteurization effectiveness were adopted as public health standards for pasteurization in the 1950s through 1980s. The colorimetric methods have a limit of detection of approximately 0.05 to 0.2% residual or contaminated raw cow's milk (3,11,13). Public health and regulatory agencies in many countries still use alkaline phosphatase reference levels of phenol as a measure of pasteurization efficacy.…”

mentioning

confidence: 99%

Evaluation of Alkaline Phosphatase Detection in Dairy Products Using a Modified Rapid Chemiluminescent Method and Official Methods

Albillos¹,

Reddy

Salter³

2011

Journal of Food Protection

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Alkaline phosphatase is a ubiquitous milk enzyme that historically has been used to verify adequate pasteurization of milk for public health purposes. Current approved methods for detection of alkaline phosphatase in milk include the use of enzyme photoactivated substrates to give readings in milliunits per liter. The U.S. and European public health limit for alkaline phosphatase in pasteurized drinks is 350 mU/liter. A modified chemiluminescent method, fast alkaline phosphatase, was compared with the approved fluorometric and chemiluminescent alkaline phosphatase methods to determine whether the modified method was equivalent to the approved methods and suitable for detecting alkaline phosphatase in milk. Alkaline phosphatase concentrations in cow's, goat's, and sheep's milk and in flavored drinks and cream were determined by three methods. Evaluations in each matrix were conducted with pasteurized samples spiked with raw milk to produce alkaline phosphatase concentrations of 2 to 5,000 mU/liter. The tests were performed by the method developer and then reproduced at a laboratory at the National Center for Food Safety and Technology following the criteria for a single laboratory validation. The results indicated that the fast alkaline phosphatase method was not significantly different from the approved chemiluminescent method, with a limit of detection of 20 to 50 mU/liter in all the studied matrices. This modified chemiluminescent method detects alkaline phosphatase in the 350 mU/liter range with absolute differences from triplicate data that are lower and within the range of the allowed intralaboratory repeatability values published for the approved chemiluminescent method.

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Alkaline phosphatase activity in pasteurized milk: A quantitative comparison of Fluorophos and colourimetric procedures

Cited by 19 publications

References 13 publications

Effects of microwave processing conditions on microbial safety and antimicrobial proteins in bovine milk

Effects of microwave processing conditions on microbial safety and antimicrobial proteins in bovine milk

A Risk Assessment Model for Enterotoxigenic Staphylococcus aureus in Pasteurized Milk: A Potential Route to Source‐Level Inference

Evaluation of Alkaline Phosphatase Detection in Dairy Products Using a Modified Rapid Chemiluminescent Method and Official Methods

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