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1 – 10 of over 1000
Article
Publication date: 14 August 2007

Hao Li, Guozhong Xie and Alan Edmondson

Traditional microbiological methods to monitor the growth or survival of microbes are very labour‐intensive and rather expensive and the knowledge acquired is not cumulative…

1587

Abstract

Purpose

Traditional microbiological methods to monitor the growth or survival of microbes are very labour‐intensive and rather expensive and the knowledge acquired is not cumulative. Predictive microbiology as an alternative approach has been developed utilizing mathematical models to predict the microbial inactivation, survival or growth during food processing. The purpose of this paper is to review the evolutions and limitations of primary mathematical models in predictive microbiology.

Design/methodology/approach

Primary models deal with the variation of microbial populations against time under particular environmental and cultural conditions. According to the behaviour of micro organisms during food processing and storage, primary models can be divided into inactivation/survival models and growth models. Literature is reviewed to assess the performance of these mathematical models.

Findings

In order to predict microbial survival or growth curves, some empirical mathematical models have been used. Most of them have no or little microbiological or physiological basis, which make the interpretation of some model parameters difficult and their performances do not match observed microbiological outcomes. To produce a more accurate mathematical model, more mechanisms are necessary to interpret model parameters with a biological basis.

Originality/value

The paper reviews the evolution and limitations of primary mathematical models, which may help future model development.

Details

British Food Journal, vol. 109 no. 8
Type: Research Article
ISSN: 0007-070X

Keywords

Article
Publication date: 11 January 2016

T. Sridevi Dhanarani, C. Shankar, P. Prakash, T. K. Poornima Priyadharshani and K. Thamaraiselvi

The purpose of this paper is to minimize environmental problems related to raw poultry manure application by stabilizing its nutrient and organic matter (OM) content. This can be…

Abstract

Purpose

The purpose of this paper is to minimize environmental problems related to raw poultry manure application by stabilizing its nutrient and organic matter (OM) content. This can be achieved by prior digestion before its application to agricultural soils.

Design/methodology/approach

In the present study, changes in physicochemical and microbial properties of poultry litter were studied in order to evaluate the suitability of using the digested (stabilized) product for soil amendment. The poultry litter was digested in autothermal thermophilic aerobic digestor (ATAD) where organic solids were degraded and the heat released during the microbial degradation was used to maintain the thermophilic temperatures ( < 50ºC) at a hydraulic retention time of about 3 d.

Findings

Results of this study showed that the poultry litter undergoes physicochemical and microbial changes similar to other digestion systems; these changes include self-heating, relative increase in Cu, Zn, Fe, Mn, P, K and NO3-N and decrease in microbial population numbers, C, OM and NH4-N contents.

Originality/value

ATAD is an effective method for the conversion of poultry litter into organic fertilizer, which can be readily applied to the agriculture land. ATAD is an eco-friendly, cost effective method which also reduces the length of stabilization.

Details

Management of Environmental Quality: An International Journal, vol. 27 no. 1
Type: Research Article
ISSN: 1477-7835

Keywords

Article
Publication date: 1 December 2005

Rezvan Pourahmad and Mahnaz Mazaheri Assadi

Yoghurt consists of approximately 60 per cent of per capita dairy consumption of Iranian people. Iranian dairy factories use commercial starters which are expensive in yoghurt…

Abstract

Purpose

Yoghurt consists of approximately 60 per cent of per capita dairy consumption of Iranian people. Iranian dairy factories use commercial starters which are expensive in yoghurt production. Moreover, yoghurt produced by these starters does not completely meet the taste of Iranian consumers. The aims of this study are to produce well qualified yoghurt from isolated native starters and to evaluate microbial, chemical and organoleptic characteristics of products.

Design/methodology/approach

The microflora of Iranian native yoghurts were isolated, purified and identified. The isolated strains were used as starter for the production of yoghurts. Sensory evaluation and measurement of pH, acidity and acetaldehyde content of the samples were carried out. Acidity, pH, acetaldehyde content, and microbial population of the best samples were measured during 21 days of cold storage. SPSS software was used for statistical analysis.

Findings

During the above mentioned storage period, acidity and acetaldehyde content increased significantly (p < 0.05). Significant decreases (p < 0.05) were observed in pH and microbial population. No significant difference in organoleptic characteristics (taste, smell and texture) were found after 21 days of cold storage.

Originality/value

Yoghurt production by native starter cultures instead of commercial ones is beneficial in respect of both economic and organoleptic aspects. The results indicate that the use of isolated native yoghurt starters in manufacturing yoghurt can be satisfactory and can also be extended to the production of yoghurt on an industrial scale.

Details

Nutrition & Food Science, vol. 35 no. 6
Type: Research Article
ISSN: 0034-6659

Keywords

Article
Publication date: 1 June 2005

E.T. Otunola and R.S. Ogunbiyi

The aim of the paper is to evaluate the microbiological and physico‐chemical characteristics of fermented pounded yam, a unique and popular food of the Igbominas of Nigeria.

526

Abstract

Purpose

The aim of the paper is to evaluate the microbiological and physico‐chemical characteristics of fermented pounded yam, a unique and popular food of the Igbominas of Nigeria.

Design/methodology/approach

Fresh pounded yam was prepared in the laboratory by a modification of the traditional method, and then fermented for varying periods of time (0‐96hrs), also essentially by the traditional method. Analysis was carried out on the products following documented and established procedures.

Findings

Data obtained indicated noticeable increases in the populations of all the groups of microorganisms investigated with increases in fermentation time, except coliforms which declined in population after 24 hours. Heating of the samples after each fermentation interval resulted in significant reductions in microbial populations such that coliforms could not even be detected after 24 hours of fermentation. Lactic acid production, an indication of flavour development, and pH drop were highest at 48 hours of fermentation. The samples also became softer with increases in fermentation period. The heated samples were considered safe microbiologically, since they contained neither coliforms nor faecal coliforms.

Research limitations/implications

The consumption of fermented pounded yam is encouraged since it is safe microbiologically and develops a desired flavour, while further research should be carried out on the nutritional benefits.

Practical implications

The findings here suggested that adequate heating after fermentation is necessary to eliminate any potential microbial contamination, and for full flavour development.

Originality/value

The results of this research contribute to the knowledge of fermented foods, especially those that are indigenous to Nigeria and West Africa.

Details

Nutrition & Food Science, vol. 35 no. 3
Type: Research Article
ISSN: 0034-6659

Keywords

Article
Publication date: 23 March 2010

S. Sarkar and A.K. Misra

Prophylactic characteristics of plain acidophilus milk could be further enhanced with the incorporation of certain probiotic or beneficial organisms. This research undertakes to…

462

Abstract

Purpose

Prophylactic characteristics of plain acidophilus milk could be further enhanced with the incorporation of certain probiotic or beneficial organisms. This research undertakes to evaluate the technological and dietetic characteristics of probiotic acidophilus milk containing Bifidobacterium bifidum and Propionibacterium freudenreichii subsp. shermanii during storage.

Design/methodology/approach

The effects of incorporation of Bifidobacterium bifidum NDRI and Propionibacterium freudenreichii subsp. shermanii MTCC 1371 as microbial additives during the manufacture and storage of acidophilus milk made from skimmed milk at 8±1 °C for seven days were evaluated. Probiotic acidophilus milk was evaluated on the basis of various technological (titratable acidity, volatile acidity, diacetyl and acetoin production and extent of proteolysis) and dietetic (lactic acid content, lactose hydrolyzing activity, antibacterial activity, viable population of lactobacilli, propionibacteria, bifidobacteria) characteristics.

Findings

Probiotic acidophilus milk obtained with the conjugated application of Lactobacillus acidophilus R, Propionibacterium freudenreichii subsp. shermanii MTCC 1371 and Bifidobacterium bifidum NDRI retained its dietetic characteristics up to seven days of storage at 8±1 °C and its consumption may be advantageous over plain acidophilus milk due to its enhanced prophylactic features.

Research limitations/implications

Mineral and vitamin estimation of probiotic acidophilus milk, animal and infant feeding trials must be conducted.

Practical implications

Conjugated application of Propionibacterium freudenreichii subsp. shermanii MTCC 1371 and Bifidobacterium bifidum NDRI as microbial additives during the manufacture of acidophilus milk may be suggested to enhance its prophylactic features.

Originality/value

Conjugated application of P. freudenreichii subsp. shermanii MTCC 1371 and B. bifidum NDRI as microbial additives with L. acidophilus R during the manufacture of acidophilus milk is suggested to enhance the prophylactic features of plain acidophilus milk. Consumption of probiotic acidophilus milk as a dietary adjunct can be recommended.

Details

British Food Journal, vol. 112 no. 3
Type: Research Article
ISSN: 0007-070X

Keywords

Article
Publication date: 8 February 2008

Nomusa R. Dlamini and Shadreck Dube

The aim of the study is to determine the microbial, physico‐chemical and nutritional changes that take place during the four‐day traditional preparation of wine from the fruits of…

1593

Abstract

Purpose

The aim of the study is to determine the microbial, physico‐chemical and nutritional changes that take place during the four‐day traditional preparation of wine from the fruits of Marula (Sclerocarya birrea subspecies Caffra) tree in Zimbabwe. It must be noted that Marula is documented as a drought‐resistant plant.

Design/methodology/approach

The fruits used in the study were taken from four trees growing in different locations. The fermenting microbial populations were isolated using potato dextrose, tomato juice and nutrient agars, and then identified to genus level using simple biochemical tests. The physico‐chemical changes determined were pH, titratable acidity, sugar and alcohol content. The alcohol content was determined using the Anton Paar beer analyzer, while nutritional changes, evaluated as changes in ascorbic acid (vitamin C) levels, were determined using the 2, 6 dichlorophenolindophenol titrimetric method.

Findings

During fermentation there was a gradual decrease in the bacterial population, and an increase in yeast counts. The pH and sugar contents decreased, while the average alcohol content increased to an average 2 per cent. The fermented Marula juice retained 72 per cent of the initial ascorbic acid content (a decrease from 133 to 96 mg/100 g) compared with orange juice subjected to similar conditions, which retained 40 per cent ascorbic acid levels (decrease from 60 to 24 mg/100 g).

Originality/value

The low pH of Marula wine could contribute to the microbiological safety of the product and relative stability of ascorbic acid. Marula wine produced after four days of fermentation is still an importance source of ascorbic acid.

Details

Nutrition & Food Science, vol. 38 no. 1
Type: Research Article
ISSN: 0034-6659

Keywords

Article
Publication date: 6 February 2017

Se-Young Ju, Jin-Ju Ko, Hee-Sun Yoon, Su-Jin Seon, Yu-Ri Yoon, Da-In Lee, So-Yeon Kim and Hye-Ja Chang

The purpose of this paper is to examine the efficacy of microbial elimination using different sanitizers in raw vegetables (cherry tomatoes, spring onions, Chinese chives, and…

Abstract

Purpose

The purpose of this paper is to examine the efficacy of microbial elimination using different sanitizers in raw vegetables (cherry tomatoes, spring onions, Chinese chives, and chicory) and to analyze the efficacy of Escherichia coli O157:H7 reduction by type of sanitizer and vegetable.

Design/methodology/approach

To assess the sanitizing effects of microbial elimination by variety of vegetable, the samples were grouped into four different washing methods: control (no sanitizer), 100 ppm chlorine, 100 ppm electrolyzed water, and 200 ppm electrolyzed water after prewashing. Subsequently, quantitative microbiological experiments were conducted to assess aerobic mesophilic plate count (APC), coliform, E. coli, and Bacillus cereus, and sensory changes of the sanitized vegetables were tested. Thereafter, measurement of the sanitizing effects on bacterial reduction after inoculation with E. coli O157:H7 was conducted.

Findings

The microbial levels of four types of vegetables ranged from 3.37 to 5.24 log CFU/g for APC, 2.41 to 5.57 log CFU/g for E. coli, 0.25 to 5.40 log CFU/g for coliform, and 0.83 to 5.44 log CFU/g for B. cereus. After three types of sanitizing treatments, microbial reduction effects showed 0.94-1.84 log CFU/g for APC, 0.56-1.00 log CFU/g for E. coli, 0.18-1.26 log CFU/g for coliform, and 0.56-1.23 log CFU/g for B. cereus (p<0.05). In sensory evaluation, there were no significant differences in taste and flavor between with and without sanitizing treatments. Regarding bacterial reduction after inoculation with E. coli O157:H7, the microbial reduction on vegetables was shown to be in the range of 0.27-1.57 log CFU/g with 100 ppm sodium hypochlorite, 0.66-3.07 log CFU/g with 100 ppm electrolyzed water, and 0.79-2.55 log CFU/g with 200 ppm electrolyzed water. Chicory, cherry tomato, and spring onion showed significant reduction levels of E. coli O157:H7 after sanitation (p<0.05).

Originality/value

This study revealed that different sanitization methods are required for different types of vegetables. Electrolyzed water treatment (100 ppm) is a more effective and safe method of washing raw vegetables. Given that the main purpose of sanitizing fresh-cut produce is to maximally reduce microorganism levels, different methods of sanitizing fresh-cut produce with an adequate washing method should be used according to vegetable type.

Details

British Food Journal, vol. 119 no. 2
Type: Research Article
ISSN: 0007-070X

Keywords

Article
Publication date: 3 March 2020

Toby Le and Sharareh Hekmat

This study aims to determine the probiotic potential of Lactobacillus rhamnosus GR-1 from Fiti sachets, in four widely consumed pulses, namely, black-eyed pea, pigeon pea, kabuli…

Abstract

Purpose

This study aims to determine the probiotic potential of Lactobacillus rhamnosus GR-1 from Fiti sachets, in four widely consumed pulses, namely, black-eyed pea, pigeon pea, kabuli chickpea and desi chickpea. The secondary objective was to determine the viability of the fermented pulses during 21 days of storage at 4°C.

Design/methodology/approach

Each pulse sample was mixed with a Fiti sachet (one gram of freeze-dried consortium of Lactobacillus rhamnosus GR-1 and Streptococcus thermophilus C106) and fermented for up to 120 h. To assess the samples’ storage potential, they were refrigerated at 4°C for 21 days. Microbial enumerations and pH measurements were collected during fermentation and storage to determine the viability and fermentation potential of Lactobacillus rhamnosus GR-1 and Fiti, respectively.

Findings

There was a significant (p = 0.01) difference in mean microbial counts in all pulse samples throughout fermentation. At 24 h of fermentation, the mean bacterial count of Lactobacillus rhamnosus GR-1 in black-eyed pea, pigeon pea, kabuli chickpea and desi chickpea were 1.32 × 109 ± 0.11, 1.01 × 109 ± 0.16, 1.52 × 109 ± 0.14 and 0.80 × 109 ± 0.05 CFU/mL, respectively. Fermentation of pigeon pea, kabuli chickpea and desi chickpea at 48 h yielded the highest bacterial count for Lactobacillus rhamnosus GR-1 while black-eyed pea reached its highest bacterial count at 72 h of fermentation. The bacterial concentration of all pulse samples remained at around 109 CFU/mL during the refrigeration period of 21 days at 4°C. Furthermore, the pH of all pulse samples were below 4.6 during both fermentation and refrigerated storage.

Originality/value

Since 2004, the Fiti initiative has economically empowered hundreds of women in East Africa by teaching them how to produce and sell probiotic yogurt containing Lactobacillus rhamnosus GR-1. As a result, Fiti probiotic yogurt was made accessible to vulnerable populations in East Africa who face malnutrition, infectious diseases and environmental toxins. Because of recent climatic changes, milk has become more expensive and inaccessible for local communities. Furthermore, this study found that black-eyed pea, pigeon pea, kabuli chickpea and desi chickpea can be viable and non-diary probiotic alternatives to the Fiti probiotic yogurt in Eastern Africa. This is also the first study of its kind to provide preliminary evidence showing pulses as non-dairy alternatives to Fiti probiotic yogurt.

Details

Nutrition & Food Science , vol. 50 no. 6
Type: Research Article
ISSN: 0034-6659

Keywords

Article
Publication date: 1 August 1998

Aleyn R.M. Barr

Some of the mechanisms involved in the microbial colonisation and biodeterioration of metalworking fluids are described in an attempt to design a more realistic and meaningful…

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Abstract

Some of the mechanisms involved in the microbial colonisation and biodeterioration of metalworking fluids are described in an attempt to design a more realistic and meaningful laboratory assay procedure. The history of bioassay techniques is reviewed and the nature and composition of metalworking fluids is examined. Maximisation of the performance of biocides against micro‐organisms and the influence of tramp oil contamination is assessed.

Details

Industrial Lubrication and Tribology, vol. 50 no. 4
Type: Research Article
ISSN: 0036-8792

Keywords

Book part
Publication date: 16 July 2015

Callie H. Burt

Heritability studies attempt to estimate the contribution of genes (vs. environments) to variation in phenotypes (or outcomes of interest) in a given population at a given time…

Abstract

Purpose

Heritability studies attempt to estimate the contribution of genes (vs. environments) to variation in phenotypes (or outcomes of interest) in a given population at a given time. This chapter scrutinizes heritability studies of adverse health phenotypes, emphasizing flaws that have become more glaring in light of recent advances in the life sciences and manifest most visibly in epigenetics.

Methodology/approach

Drawing on a diverse body of research and critical scholarship, this chapter examines the veracity of methodological and conceptual assumptions of heritability studies.

Findings

The chapter argues that heritability studies are futile for two reasons: (1) heritability studies suffer from serious methodological flaws with the overall effect of making estimates inaccurate and likely biased toward inflated heritability, and, more importantly (2) the conceptual (biological) model on which heritability studies depend – that of identifiably separate effects of genes versus the environment on phenotype variance – is unsound. As discussed, contemporary bioscientific work indicates that genes and environments are enmeshed in a complex (bidirectional, interactional), dynamic relationship that defies any attempt to demarcate separate contributions to phenotype variance. Thus, heritability studies attempt the biologically impossible. The emerging research on the importance of microbiota is also discussed, including how the commensal relationship between microbial and human cells further stymies heritability studies.

Originality/value

Understandably, few sociologists have the time or interest to be informed about the methodological and theoretical underpinnings of heritability studies or to keep pace with the incredible advances in genetics and epigenetics over the last several years. The present chapter aims to provide interested scholars with information about heritability and heritability estimates of adverse health outcomes in light of recent advances in the biosciences.

Details

Genetics, Health and Society
Type: Book
ISBN: 978-1-78350-581-4

Keywords

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