The heat resistance and spoilage potential of aerobic mesophilic and thermophilic spore forming bacteria isolated from Chinese milk powders

Sadiq, Faizan Ahmed; Li, Yun; Liu, TongJie; Flint, Steve; Zhang, Guohua; Yuan, Lei; Pei, Zhipeng; He, Guoqing

doi:10.1016/j.ijfoodmicro.2016.09.009

Cited by 78 publications

(43 citation statements)

References 59 publications

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“…Lactose fermentation analysis was done on the remaining 32 B. licheniformis isolates and they also gave negative results. This finding is supported by Sadiq and others (), who managed to isolate B. licheniformis strains from Chinese dairy milk powder that did not produce β‐galactosidase. In addition, most of our B. licheniformis isolates were able to form biofilm in 1% RWPC80 without lactose or minerals on SS (Figure and ).…”

Section: Resultssupporting

confidence: 58%

The Potential Source of B. licheniformis Contamination During Whey Protein Concentrate 80 Manufacture

Zain

Bennett

Flint

2017

Journal of Food Science

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The objective of this study was to determine the possible source of predominant Bacillus licheniformis contamination in a whey protein concentrate (WPC) 80 manufacturing plant. Traditionally, microbial contaminants of WPC were believed to grow on the membrane surfaces of the ultrafiltration plant as this represents the largest surface area in the plant. Changes from hot to cold ultrafiltration have reduced the growth potential for bacteria on the membrane surfaces. Our recent studies of WPCs have shown the predominant microflora B. licheniformis would not grow in the membrane plant because of the low temperature (10 °C) and must be growing elsewhere. Contamination of dairy products is mostly due to bacteria being released from biofilm in the processing plant rather from the farm itself. Three different reconstituted WPC media at 1%, 5%, and 20% were used for biofilm growth and our results showed that B. licheniformis formed the best biofilm at 1% (low solids). Further investigations were done using 3 different media; tryptic soy broth, 1% reconstituted WPC80, and 1% reconstituted WPC80 enriched with lactose and minerals to examine biofilm growth of B. licheniformis on stainless steel. Thirty-three B. licheniformis isolates varied in their ability to form biofilm on stainless steel with stronger biofilm in the presence of minerals. The source of biofilms of thermo-resistant bacteria such as B. licheniformis is believed to be before the ultrafiltration zone represented by the 1% WPC with lactose and minerals where the whey protein concentration is about 0.6%.

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Section: Resultssupporting

confidence: 58%

The Potential Source of B. licheniformis Contamination During Whey Protein Concentrate 80 Manufacture

Zain

Bennett

Flint

2017

Journal of Food Science

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“…; Sadiq et al . ). Such differences in findings may furthermore be attributed to unclarity in identification of species or may be caused by strain‐to‐strain variation.…”

Section: Discussionmentioning

confidence: 97%

“…), but not always (Sadiq et al . ). Thermophilic species, such as Geobacillus spp., are notorious for producing highly heat‐resistant spores, which generally survive more severe heat treatments than spores of mesophilic species.…”

Section: Introductionmentioning

confidence: 97%

“…Spores of bacterial species that are often encountered in dairy products belong to a wide range of aerobic and anaerobic species with different optimal growth temperatures and growth requirements (Sadiq et al 2016;Doll et al 2017). Most mesophilic spore formers, including many Bacillus spp.…”

Section: Introductionmentioning

confidence: 99%

“…The optimal growth temperature of species often correlates with the thermal resistance of their spores (reviewed in den Besten et al 2018), but not always (Sadiq et al 2016). Thermophilic species, such as Geobacillus spp., are notorious for producing highly heat-resistant spores, which generally survive more severe heat treatments than spores of mesophilic species.…”

Section: Introductionmentioning

confidence: 99%

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Spores in dairy – new insights in detection, enumeration and risk assessment

Eijlander

Hekezen

Bienvenue³

et al. 2019

Int J of Dairy Tech

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The performance of the ISO method for the ‘Enumeration of the Specially Thermoresistant Spores of Thermophilic Bacteria in Dried Milk’ (ISO/TS27265; 2009) was compared with a more practical method. Both were tested for predictability of spoilage of UHT treated reconstituted milk. The data show that heating for 30 min at 100 °C has the same predictive value as heating for 30 min at 106 °C, provided that specifications are increased 1 log10 and the use of TSA as a cultivation medium is recommended over PCMA. Predictability of spoilage using classical plating methods is furthermore discussed in relation to variation in spore heat resistance of spores commonly present in the dairy industry.

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