Thermal Processing of Packaged Foods

Holdsworth, S. Donald

doi:10.1007/978-0-387-72250-4

Cited by 90 publications

(66 citation statements)

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“…Using the capillary tube method (8), the D 121°C value (decimal reduction time, i.e., time at 121°C required to kill 90% of the spores) and the Z value (temperature required to change the D value by 1 log) for this spore crop were calculated to be 0.23 min and 7.66°C (data not shown). This is comparable to the D 121°C and Z values of 0.21 min and 10°C, respectively, for C. botulinum (1).…”

supporting

confidence: 80%

PCR-Based Method Using Propidium Monoazide To Distinguish Viable from Nonviable Bacillus subtilis Spores

Rawsthorne

Dock

Jaykus

2009

Appl Environ Microbiol

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This paper describes a molecular-based method which is able to discriminate between viable and inactivated Bacillus subtilis spores by utilizing the DNA-intercalating dye propidium monoazide. The approach should be valuable in our attempt to employ molecular methods to streamline the evaluation of process validation using bacterial endospores.There is a continued need for the development and application of rapid methods for the detection and enumeration of bacterial endospores, especially as investigators seek to evaluate the efficacy of emerging food-processing technologies. For such thermal-process validation studies, surrogates of Clostridium botulinum, including Bacillus subtilis and Clostridium sporogenes, are commonly used. Currently, standard plating methods remain the "gold standard" for enumeration of survivors of these processes. Molecular amplification approaches, such as quantitative real-time PCR (qPCR), have shown promise but have not been applied to the enumeration of surviving spores because (i) release of nucleic acid from spores is difficult and (ii) the detection of DNA does not necessarily equate with the presence of viable spores.Recently, the DNA-intercalating agents ethidium monoazide and propidium monoazide (PMA) have been used in conjunction with qPCR for the selective detection of live cells of food-borne pathogens (2, 3, 5, 6, 9). These compounds selectively penetrate the membranes of dead cells and form stable DNA monoadducts upon photolysis, resulting in DNA which cannot be amplified by PCR (3). To our knowledge, this technique has not yet been applied to bacterial spores. The purpose of this study was to demonstrate that DNA-intercalating agents could be used in conjunction with qPCR for the selective enumeration of viable, but not inactivated, spores of B. subtilis.All media were supplied by Difco (Franklin Lakes, NJ), and chemicals were obtained from Sigma-Aldrich (St. Louis, MO). Bacillus subtilis ATCC 35021 (American Type Culture Collection, Manassas, VA) was grown overnight in 10 ml of brain heart infusion broth at 37°C. Five-hundred-microliter aliquots of the vegetative cells were spread onto 150-by 15-mm petri dishes containing sporulation agar comprised of 13 g/liter nutrient broth, 15 g/liter agar, 0.51 g/liter MgSO 4 ⅐ 7H 2 O, 0.97 g/liter KCl, 0.2 g/liter CaCl 2 ⅐ 2H 2 O, 3 mg/liter MnSO 4 ⅐ H 2 0, and 0.5 mg/liter FeSO 4 ⅐ 7H 2 O. The plates were incubated aerobically at 37°C for 3 to 5 days until more than 95% of cells had sporulated, as determined by phase-contrast microscopy. Spores were harvested in cold, sterile distilled water (dH 2 O) and washed repeatedly (5 to 10 times). Before final resuspension, the spores were treated with 80 U/ml DNase (SigmaAldrich, St. Louis, MO) at 37°C for 90 min (to degrade residual DNA), with subsequent DNase inactivation by heating at 65°C for 10 min. The final populations were approximately 10 7 spores/ml, and crops were stored at 4°C until use. Using the capillary tube method (8), the D 121°C value (decimal reduction time, i.e., tim...

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supporting

confidence: 80%

PCR-Based Method Using Propidium Monoazide To Distinguish Viable from Nonviable Bacillus subtilis Spores

Rawsthorne

Dock

Jaykus

2009

Appl Environ Microbiol

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“…Current commercial thermal processes are based on the assumption of first-order microbial inactivation kinetics information (Holdsworth, 1997;Jay, 1996;Stumbo, 1973;Teixeira, 1992), which leads to logarithmic log-linear survivor curves. Many researchers, however, have observed nonlog-linear behaviors characterized by a broad shoulder during initial phase of heat treatment (Hills & Mackey, 1995;Linton, Carter, Pierson & Hackney, 1995).…”

Section: Introductionmentioning

confidence: 99%

Performance evaluation of aluminum test cell designed for determining the heat resistance of bacterial spores in foods

Chung¹,

Birla²,

Tang³

2008

LWT - Food Science and Technology

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“…2 Thn. 2017 Versi online : http://journal.upgris.ac.id/index.php Activation Energy (AE) atau energi aktivasi (ea) adalah energi minimal yang harus dimiliki molekul untuk melakukan suatu reaksi (Holdsworth, 1997) dalam hal ini adalah reaksi untuk terbentuknya ffa. Ea dapat digunakan sebagai parameter untuk mengetahui jumlah energi minimum yang digunakan untuk mengaktifkan suatu reaksi sebagai akibat dari pertemuan molekul-molekul didalam tumbukan atau getaran, sedangkan jumlah frekuensi tumbukan antar molekul-molekul selama reaksi berlangsung bisa ditunjukkan dengan adanya konstanta faktor frekuensi (ko).…”

Section: Abstrakunclassified

Energi Aktivasi Perubahan Nilai Free Fatty Acid pada Abon Ikan Lele Dumbo (Clarias sp) Selama Penyimpanan

Anggo

2018

JIPHP

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The accumulation of free fatty acid (FFA) 97/RT) . Keywords: activation energy; arrhenius; catfish; ; free fatty acid; Shreded meat fish ABSTRAK Salah satu penyebab timbulnya bau tidak enak pada abon ikan adalah terakumulasinya senyawa asam lemak bebas / free fatty acid (FFA) akibat proses hidrolisis dari lemak pada abon tersebut. Perlakuan panas selama penyimpanan abon akan semakin memicu terbentuknya ffa sehingga baunya akan semakin tidak enak. Penelitian ini bertujuan untuk memodelkan fenomena perubahan kualitas abon lele dumbo dari parameter nilai ffa sebagai akibat perlakuan suhu dan waktu, dengan cara mencari nilai energi aktivasi perubahan nilai ffa tersebut. Materi yang dipelajari adalah abon ikan lele dumbo (Clarias sp). Peralatan yang digunakan adalah container penyimpan abon yang telah didesain pada suhu tertentu yaitu 10, 25, 35 dan 45 o C. Waktu pengambilan sampel dilakukan pada hari ke-1, 8, 16, 24 dan 32. Metode penentuan energi aktivasi dengan pendekatan metode Arrhenius berdasarkan parameter perubahan nilai ffa. Hasil penelitian menunjukkan bahwa laju peningkatan nilai ffa terjadi seiring dengan pertambahan waktu dan suhu penyimpanan. Hasil perhitungan energi aktivasi pada reaksi orde pertama diperoleh nilai 22,97 kj/mol dengan faktor frequensi (ko) sebesar 211,706 (1/hari). Model persamaan Arrhenius yang diperoleh adalah k= 211,706. e 97/RT) . Kata kunci: Abon; lele; free fatty acid; Arrhenius; energi aktivasi. PENDAHULUAN

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Thermal Processing of Packaged Foods

Cited by 90 publications

References 0 publications

PCR-Based Method Using Propidium Monoazide To Distinguish Viable from Nonviable Bacillus subtilis Spores

PCR-Based Method Using Propidium Monoazide To Distinguish Viable from Nonviable Bacillus subtilis Spores

Performance evaluation of aluminum test cell designed for determining the heat resistance of bacterial spores in foods

Energi Aktivasi Perubahan Nilai Free Fatty Acid pada Abon Ikan Lele Dumbo (Clarias sp) Selama Penyimpanan

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