Comparative Growth Inhibition of Bread Spoilage Fungi by Different Preservative Concentrations Using a Rapid Turbidimetric Assay System

Bread and intermediate moisture bakery products are mainly spoiled by yeasts and filamentous fungi. The inoculum load and preservation system used determines their shelf life. To extend the shelf life of such commodities, the use of chemical preservatives is the most common way to try and control the initiation of mold spoilage of bread. This study has utilized a rapid turbidimetric assay system (Bioscreen C) to examine the temporal efficacy of calcium propionate (CP) and potassium sorbate (PS) for controlling the growth of important bread spoilage fungi. The objectives were to compare the temporal growth of strains of three important spoilage fungi Hyphopichia burtonii (HB17), Paecilomyces variotii (PV11), and Penicillium roqueforti (PR06) isolated from visibly molded bread to (a) different concentrations of CP and PS (0–128 mM), (b) temperatures (25°C, 30°C), (c) water activity (aw; 0.95, 0.97), and (d) pH (5.0, 5.5). All three abiotic factors, pH, aw, and temperature, and preservative concentrations influenced the relative growth of the species examined. In general, PS was more effective than CP in inhibiting the growth of the strains of these three species. In addition, the Time to Detection (TTD) for the efficacy of the preservatives under the interacting abiotic factors was compared. The strain of Paecilomyces variotii (PV10) was the most tolerant to the preservatives, with the shortest TTD values for both preservatives. P. roqueforti was the most sensitive with the longest TTD values under all conditions examined. These results are discussed in the context of the evolution of resistance to food-grade preservatives by such spoilage fungi in bakery products.

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Prediction of Microbial Spoilage and Shelf-Life of Bakery Products Through Hyperspectral Imaging

IEEE Access ◽

10.1109/access.2020.3026925 ◽

2020 ◽

Vol 8 ◽

pp. 176986-176996

Author(s):

Zainab Saleem ◽

Muhammad Hussain Khan ◽

Muhammad Ahmad ◽

Ahmed Sohaib ◽

Hamail Ayaz ◽

...

Keyword(s):

Shelf Life ◽

Hyperspectral Imaging ◽

Bakery Products ◽

Microbial Spoilage

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Impacts of Climate Change Interacting Abiotic Factors on Growth, aflD and aflR Gene Expression and Aflatoxin B1 Production by Aspergillus flavus Strains In Vitro and on Pistachio Nuts

Toxins ◽

10.3390/toxins13060385 ◽

2021 ◽

Vol 13 (6) ◽

pp. 385

Author(s):

Alaa Baazeem ◽

Alicia Rodriguez ◽

Angel Medina ◽

Naresh Magan

Keyword(s):

Climate Change ◽

Gene Expression ◽

Water Stress ◽

Aspergillus Flavus ◽

Aflatoxin B1 ◽

Abiotic Factors ◽

Pistachio Nuts ◽

Significant Difference ◽

Spoilage Fungi

Pistachio nuts are an important economic tree nut crop which is used directly or processed for many food-related activities. They can become colonized by mycotoxigenic spoilage fungi, especially Aspergillus flavus, mainly resulting in contamination with aflatoxins (AFs), especially aflatoxin B1 (AFB1). The prevailing climate in which these crops are grown changes as temperature and atmospheric CO2 levels increase, and episodes of extreme wet/dry cycles occur due to human industrial activity. The objectives of this study were to evaluate the effect of interacting Climate Change (CC)-related abiotic factors of temperature (35 vs. 37 °C), CO2 (400 vs. 1000 ppm), and water stress (0.98–0.93 water activity, aw) on (a) growth (b) aflD and aflR biosynthetic gene expression and (c) AFB1 production by two strains A. flavus (AB3, AB10) in vitro on milled pistachio-based media and when colonizing layers of shelled raw pistachio nuts. The A. flavus strains were resilient in terms of growth on pistachio-based media and the colonisation of pistachio nuts with no significant difference when exposed to the interacting three-way climate-related abiotic factors. However, in vitro studies showed that AFB1 production was significantly stimulated (p < 0.05), especially when exposed to 1000 ppm CO2 at 0.98–0.95 aw and 35 °C, and sometimes in the 37 °C treatment group at 0.98 aw. The relative expression of the structural aflD gene involved in AFB1 biosynthesis was decreased or only slightly increased, relative to the control conditions at elevated CO, regardless of the aw level examined. For the regulatory aflR gene expression, there was a significant (p < 0.05) increase in 1000 ppm CO2 and 37 °C for both strains, especially at 0.95 aw. The in situ colonization of pistachio nuts resulted in a significant (p < 0.05) stimulation of AFB1 production at 35 °C and 1000 ppm CO2 for both strains, especially at 0.98 aw. At 37 °C, AFB1 production was either decreased, in strain AB3, or remained similar, as in strain AB10, when exposed to 1000 ppm CO2. This suggests that CC factors may have a differential effect, depending on the interacting conditions of temperature, exposure to CO2 and the level of water stress on AFB1 production.

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Effects of Storage Temperature and Preservative Treatment on Shelf Life of the Pond-Raised Freshwater Fish, Silver Perch (Bidyanus bidyanus)

Journal of Food Protection ◽

10.4315/0362-028x-64.10.1584 ◽

2001 ◽

Vol 64 (10) ◽

pp. 1584-1591 ◽

Cited By ~ 39

Author(s):

A. GELMAN ◽

L. GLATMAN ◽

V. DRABKIN ◽

S. HARPAZ

Keyword(s):

Shelf Life ◽

Cold Storage ◽

Storage Temperature ◽

Storage Period ◽

Potassium Sorbate ◽

Test Results ◽

Bacterial Composition ◽

Fish Flesh ◽

Microbiological Characteristics ◽

Initial Load

Sensory and microbiological characteristics of pond-raised freshwater silver perch (Bidyanus bidyanus) fish, during cold storage over a period of 25 days were evaluated. Whole fish (averaging 400 g each) were stored in cold storage rooms at either 0 to 2°C, 5°C, or 5°C + potassium sorbate as a preservative. The organoleptic and hypoxanthine test results show that the treatment of potassium sorbate can slow the process of spoilage by about 5 days. Yet, the most important factor affecting the shelf life of these fish is the storage temperature. Keeping the fish at 0 to 2°C can prolong the storage prior to spoilage by 10 days compared with those kept at 5°C. These results obtained through organoleptic tests are corroborated by both the chemical (hypoxanthine and total volatile basic nitrogen) and to some extent by the physical (cosmos) tests. The initial total bacteriological counts were 5 × 102 CFU/cm2 for fish surface and <102 CFU/g for fish flesh, and these counts rose continuously, reaching about 106 CFU/g (0 to 2°C) and 107 CFU/g (5°C) in flesh and 107 to 108 CFU/cm2 on the surface by the end of the storage period. The addition of potassium sorbate led to a smaller increase in bacterial numbers, especially during the first 15 days. Bacterial composition fluctuated during storage. The initial load on the fish surface was predominantly mesophilic and gram positive and consisted mostly (80%) of Micrococci, Bacillus, and Corynebacterium. During the next 10 days, these bacteria were practically replaced by gram-negative flora comprised mostly of Pseudomonas fluorescens that rapidly increased with storage time and accounted for 95% after 15 days.

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Extension of Shelf Life of Whole and Peeled Shrimp with Organic Acid Salts and Bifidobacteria

Journal of Food Protection ◽

10.4315/0362-028x-62.1.51 ◽

1999 ◽

Vol 62 (1) ◽

pp. 51-56 ◽

Cited By ~ 47

Author(s):

MOSFFER M. AL-DAGAL ◽

WAEL A. BAZARAA

Keyword(s):

Organic Acid ◽

Shelf Life ◽

Generation Time ◽

Sodium Acetate ◽

East Coast ◽

Sensory Characteristics ◽

Potassium Sorbate ◽

Lag Phase ◽

Organic Acid Salts ◽

Acid Salts

Microbiological and sensory characteristics of treated whole and peeled shrimp from the east coast of Saudi Arabia were evaluated. Shrimp samples were treated with organic acid salts with or without Bifidobacterium breve culture and stored in ice. Peeling alone extended the microbiological shelf life by 4 days. Treatment of whole shrimp with sodium acetate alone or potassium sorbate with bifidobacteria prolonged the microbiological shelf life by 3 days and increased the microbial generation time from 12.8 h (control) to 30.1 h or 31.4 h, respectively. The microbiological and sensory shelf life of peeled shrimp treated with sodium acetate was more than 17 days. Sodium acetate extended the microbial lag phase and lengthened the generation time (38.7 h compared to 15.8 h for the control). Micrococci and coryneforms were the predominant microorganisms in whole shrimp during storage. Treatment with sodium acetate maintained better sensory characteristics for peeled shrimp than potassium sorbate combined with bifidobacteria.

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Shelf-life of bakery products; Hygiene and safety

Baking for Profit ◽

10.3362/9781780444536.005 ◽

2000 ◽

pp. 53-64

Author(s):

George Bathie

Keyword(s):

Shelf Life ◽

Bakery Products

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Shelf-life Modeling of Bakery Products by Using Oxidation Indices

Journal of Agricultural and Food Chemistry ◽

10.1021/jf063004h ◽

2007 ◽

Vol 55 (5) ◽

pp. 2004-2009 ◽

Cited By ~ 44

Author(s):

Sonia Calligaris ◽

Lara Manzocco ◽

Giuditta Kravina ◽

Maria Cristina Nicoli

Keyword(s):

Shelf Life ◽

Bakery Products

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Effect of potassium sorbate and gamma irradiation on the shelf-life of Hilsa shad, Tenualosa ilisha (Hamilton, 1822) at low temperature

Jahangirnagar University Journal of Biological Sciences ◽

10.3329/jujbs.v6i2.36592 ◽

2018 ◽

Vol 6 (2) ◽

pp. 67-73

Author(s):

Tasnoba Firoze Sheuty ◽

Md Kamrujjaman ◽

Mahfuza Islam ◽

Md Afzal Hossain ◽

Roksana Haque

Keyword(s):

Low Temperature ◽

Gamma Irradiation ◽

Shelf Life ◽

Potassium Sorbate ◽

Organoleptic Evaluation ◽

Fish Flesh ◽

Increasing Trend ◽

Tenualosa Ilisha

Shelf-life of potassium sorbate (2%) and gamma irradiation (2kGy) treated Hilsa shad (Tenualosa ilisha) were determined after storing at 0oC and 4oC for a period of upto 35 days. Organoleptic evaluation showed that control, potassium sorbate treated and irradiated samples remained acceptable upto 21, 28 and 35 days of storage periods respectively at 00 C. Whereas, the same samples remained acceptable upto 7, 14 and 21 days of storage respectively at 40 C. Tyrosine and pH of fish flesh increased with the increasing of storage periods in all samples but, this increasing trend was somewhat lower in irradiated sample compare to other samples. Microbial assessment showed the best results in case of irradiated sample and remained within the acceptable limit.Jahangirnagar University J. Biol. Sci. 6(2): 67-73, 2017 (December)

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SHELF-LIFE EXTENSION OF RAW BROWN SHRIMP (PENAEUS AZTECUS) WITH POTASSIUM SORBATE IN ICES AND DIPS

Journal of Food Quality ◽

10.1111/j.1745-4557.1989.tb00326.x ◽

1989 ◽

Vol 12 (3) ◽

pp. 243-248 ◽

Cited By ~ 3

Author(s):

MARK A. HARRISON ◽

LOUIS J. HEINSZ

Keyword(s):

Shelf Life ◽

Brown Shrimp ◽

Life Extension ◽

Potassium Sorbate ◽

Shelf Life Extension ◽

Penaeus Aztecus

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Use of Sorbates in Meat Products, Fresh Poultry and Poultry Products: A Review1

Journal of Food Protection ◽

10.4315/0362-028x-45.4.374 ◽

1982 ◽

Vol 45 (4) ◽

pp. 374-383 ◽

Cited By ~ 55

Author(s):

MICHAEL C. ROBACH ◽

JOHN N. SOFOS

Keyword(s):

Adverse Effects ◽

Shelf Life ◽

Sodium Nitrite ◽

Antimicrobial Agents ◽

Sorbic Acid ◽

Meat Products ◽

Potassium Sorbate ◽

Processed Meat ◽

Poultry Products ◽

Wide Range

Extensive research conducted in recent years has examined the efficiency of both potassium sorbate and sorbic acid (sorbates) as antimicrobial agents in a wide range of processed meat, and fresh and processed poultry products. In addition to their action against pathogens, effects of sorbates on product shelf-life, sensory qualities, and nitrosamine formation have also been examined in laboratory, pilot plant and commercial scale studies. The use of sorbates in these products appears to extend several benefits to both producers and consumers. Extensive studies involving bacon have shown a major reduction in nitrosamine levels associated with inclusion of potassium sorbate and reduction of sodium nitrite in the curing brine. Simultaneously, the low sodium nitrite/potassium sorbate combinations have maintained or even improved antibotulinal activity in temperature-abused products. In addition, potassium sorbate or sorbic acid have delayed growth and toxin production by Clostridium botulinum in other products including cooked and cured red meat and poultry sausages. The compounds have also been shown to extend the shelf-life and delay growth of other pathogenic microorganisms in several products including bacon; cooked, cured meat sausages; cooked, cured or uncured poultry products; fresh poultry; and other meats, including dry cured and fermented products. Sensory evaluation studies have shown that sorbate levels recommended for use in these products (0.26%) do not have adverse effects on product quality characteristics. Allergic type symptoms attributed to experimental bacon from one study were not linked directly with either potassium sorbate or other formulation ingredients, and all available information does not indicate development of any adverse effects from use of sorbates at recommended levels. In summary, the results of studies conducted in meat products indicate that sorbates deserve consideration as potential alternatives to current formulations or processes involved in the manufacture of processed meat and fresh and processed poultry products.

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