Growth and location of bacterial colonies within dairy foods using microscopy techniques: a review

Abstract

The growth, location, and distribution of bacterial colonies in dairy products are important factors for the ripening and flavor development of cheeses, yogurts, and soured creams. Starter, non-starter, spoilage, and pathogenic bacteria all become entrapped in the developing casein matrix of dairy foods. In order to visualize these bacterial colonies and the environments surrounding them, microscopy techniques are used. The use of various microscopy methods allow for the rapid detection, enumeration, and distribution of starter, non-starter and pathogenic bacteria in dairy foods. Confocal laser scanning microscopy is extensively utilized to identify bacteria location via the use of fluorescent dyes. Further study is needed in relation to the development of micro- gradients and localized ripening parameters in dairy products due to the location of bacteria at the protein–fat interface. Development in the area of bacterial discrimination using microscopy techniques and fluorescent dyes/tags is needed as the benefits of rapidly identifying spoilage/pathogenic bacteria early in product manufacture would be of huge benefit in relation to both safety and financial concerns.

Probiotics– the journey continues

“…; Hickey et al . ,b). He discussed the complexity of the cheese ripening process, and how several factors influence the cheese matrix microstructure as well as the bacteria entrapped within this and their metabolic activity, and how these bacteria in turn influence the cheese matrix.…”

“…Bacteria are more likely to be found at the fat–protein interface or within whey pockets (Hickey et al . ) where they are in close proximity or direct contact with milk fat globules or their membranes.…”

“…Each bacterial cell can form a colony, which becomes immobilised within the cheese matrix (Jeanson et al 2011). Bacteria are more likely to be found at the fat-protein interface or within whey pockets (Hickey et al 2015b) where they are in close proximity or direct contact with milk fat globules or their membranes.…”

Physical, chemical, and microstructural properties of nonfat yogurts fortified with the addition of tara gum alone or in combination with buttermilk powder

“…Moreover, TBY1 and TBY2 had lower pH and higher titratable acidity values than other yogurts during storage. More amount of MFGM in BP that help to improve metabolism of starter bacteria may explain the lower pH value in the yogurts fortified with BP (Le et al, 2011;Martinovic et al, 2013).…”

Game theoretic consideration of transgenic bacteria in the human gut microbiota as a pro-biotic prophylactic for metabolic syndrome

“…Hence defectors will drive co-operators to extinction. As an aside, the ability to distinguish emergent patterns of microbial interactions would provide the basis of pattern recognition for colony detection, from faecal microbiology cultures or during endoscopic procedures (for example, with engineered Green Fluorescence Protein in transgenic bacteria [21], borrowing methodological aspects of Borisova et al [22] in the clinic, cultured colony detection [23,24] in the laboratory and colony detection summarised by Hickley et al [25]) with which to visualise the spatial-temporal distribution of the most beneficial and effective densities of the probiotic.…”