Temperature abuse initiating yeast growth in yoghurt

Viljoen, Bennie C.; Lourens-Hattingh, Analie; Ikalafeng, Bridget; Péter, Gábor

doi:10.1016/s0963-9969(02)00138-2

Cited by 51 publications

(35 citation statements)

References 13 publications

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“…At 8 and 20°C, a rapid increase was observed from d 3, except for unflavored samples at 20°C where the increase started at d 0. Unlike our results, Viljoen et al (2003) found that, at 5 and 10°C, yeasts increased significantly only after 10 d, reaching 5 log cfu/g at d 15 of storage. The delay in yeast growth in our samples during the first days, especially in fruit samples, was likely related to the presence of potassium sorbate in the fruit puree in a rate of 0.13%, corresponding to a final concentration in the product of 156.8 ppm; this additive is well known for its inhibitory effect against yeast flora and is widely used as antimicrobial in the food industry (Mihyar et al, 1997).…”

Section: Microbiological Shelf Lifecontrasting

confidence: 99%

Microbiological shelf life at different temperatures and fate of Listeria monocytogenes and Escherichia coli inoculated in unflavored and strawberry yogurts

Tirloni

Bernardi

Colombo

et al. 2015

Journal of Dairy Science

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Three different trials were performed on unflavored and strawberry yogurts produced in a small-scale dairy plant. In the first trial, the microbiological shelf life of the products was evaluated at 4, 8, and 20°C. At 4°C the product showed low total viable counts until the end of the trial (d 35=3.0±0.7 and 1.5±0.0 log cfu/g in unflavored and strawberry yogurt, respectively). The loads were lower in strawberry yogurt at 4°C compared with unflavored yogurt because of the antimicrobial activity exerted by potassium sorbate present in the fruit puree added. Yeasts were confirmed to be the specific spoilage agents of this product, reaching rapidly high loads with thermal abuse (5.9-7.4 log cfu/g at d 18). In the second trial, Escherichia coli and especially Listeria monocytogenes added at 2 concentrations (2 and 5 log cfu/g) showed a rapid decrease in both types thanks to the acidic conditions provided by the products, but L. monocytogenes was very resistant; its presence was always detected until the end of the period considered (d 68). In the third trial, no statistically significant differences were detected between wild and acid-adapted strains of L. monocytogenes added to the products, due to the quick adaptation that probably occurred after inoculation.

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Section: Microbiological Shelf Lifecontrasting

confidence: 99%

Microbiological shelf life at different temperatures and fate of Listeria monocytogenes and Escherichia coli inoculated in unflavored and strawberry yogurts

Tirloni

Bernardi

Colombo

et al. 2015

Journal of Dairy Science

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“…Yarrowia lipolytica has been identified, at lower frequencies, in a number of other dairy products: in milk of cow, ewe and water buffalo (Baroiller & Schmidt, 1990;Chen et al, 2010;Corbo et al, 2001;Suárez & Iñigo, 1982), in (traditionally) fermented milk products such as yoghurt, kefir, nunu and amasi (Akabanda et al, 2010;Bai et al, 2010;Fröhlich-Wyder, 2003;Gadaga et al, 2000;LourensHattingh & Viljoen, 2002;Rohm et al, 1992;Viljoen et al, 2003), as well as in butter, cream and margarine (Bours & Mossel, 1973;Lanciotti et al, 1992;Lopandic et al, 2006). In yoghurt, the use of Y. lipolytica in starter cultures, to support the growth of probiotic bacteria, has been considered (Lourens-Hattingh & Viljoen, 2002).…”

Section: Natural Occurrence Of Yarrowia Lipolytica In Foodmentioning

confidence: 99%

Yarrowia lipolytica: Safety assessment of an oleaginous yeast with a great industrial potential

Groenewald

Boekhout

Neuvéglise

et al. 2013

Critical Reviews in Microbiology

395

288

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Yarrowia lipolytica has been developed as a production host for a large variety of biotechnological applications. Efficacy and safety studies have demonstrated the safe use of Yarrowia-derived products containing significant proportions of Yarrowia biomass (as for DuPont's eicosapentaenoic acid-rich oil) or with the yeast itself as the final product (as for British Petroleum's single-cell protein product). The natural occurrence of the species in food, particularly cheese, other dairy products and meat, is a further argument supporting its safety. The species causes rare opportunistic infections in severely immunocompromised or otherwise seriously ill people with other underlying diseases or conditions. The infections can be treated effectively by the use of regular antifungal drugs, and in some cases even disappeared spontaneously. Based on our assessment, we conclude that Y. lipolytica is a ''safe-to-use'' organism.

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“…The major factors for determining the shelf life and quality of yoghurt products are Y&M growth, development of off‐flavours as well as survival of probiotic microbial species (Robinson et al. 2002; Viljoen et al. 2003).…”

Section: Preservation Of Dairy Products By Co2 Additionmentioning

confidence: 99%

The use of carbon dioxide in the processing and packaging of milk and dairy products: A review

Singh

Wani

Karim

et al. 2011

Int J of Dairy Tech

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The upswing in consumer demand for fresh and high quality preservative-free foods has led to the development of modified atmosphere packaging (MAP). Increasingly, MAP is being used with high carbon dioxide (CO2) concentration as well as CO2/N2 gas mixes. Modified atmosphere packaging or 'gas flushing' as it is also known is an increasingly popular technique used to extend the shelf life (both quality and safety) of a number of dairy products. Carbon dioxide is an active constituent of MAP, naturally present in freshly drawn raw milk. Addition of CO2 to raw milk or flushing the package headspace has proved to be a simple and cost-effective method, depending upon the initial microbiological quality of the food product. Carbon dioxide addition through MAP or direct injection as an economically affordable shelf life extension strategy is used commercially worldwide for some dairy products. The development of food packaging machines with integrated gas flushing capabilities and the supply of 'food grade' gases allow dairy foods manufacturers to enhance the quality of their products. This review presents a broad spectrum of current research and the current trends with respect to CO2 as a natural microbial hurdle with special focus on its precise mechanism and its role in quality improvement of dairy products

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Temperature abuse initiating yeast growth in yoghurt

Cited by 51 publications

References 13 publications

Microbiological shelf life at different temperatures and fate of Listeria monocytogenes and Escherichia coli inoculated in unflavored and strawberry yogurts

Microbiological shelf life at different temperatures and fate of Listeria monocytogenes and Escherichia coli inoculated in unflavored and strawberry yogurts

Yarrowia lipolytica: Safety assessment of an oleaginous yeast with a great industrial potential

The use of carbon dioxide in the processing and packaging of milk and dairy products: A review

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