Microbiological quality assurance of edible table spreads in new product development

Abstract

The microbiological quality assurance (MQA) of edible table spreads, including milk fat, margarine type and blended products having fat contents in the range 5–80% by weight, in new product development is considered in relation to the sampling and monitoring of marker microorganisms, hazard and risk analyses, challenge testing, preservative efficacy testing and the modelling of the growth of spoilage micro‐organisms in compartmentalized food emulsion systems. It is shown that the use of ingredient and process technologies to implement ecological principles of MQA plays a major role in the development of safe, wholesome and shelf stable edible table spreads.

Oil‐in‐Water Emulsion as a Model System to Study the Growth of Escherichia coli O157:H7 in a Heterogeneous Food System

“…The density of the cells at the stationary phase also decreased as the hexadecane concentration increased. This phenomenon is in agreement with other studies (Brocklehurst and others 1993;Brocklehurst 1995a;Charteris 1995;Charteris 1996). The increase in generation time of bacteria in the emulsions may be due to growth under several limitations.…”

Storage related changes in ghee-based low-fat spread

“…Ibrahim et al (1994) and Reddy et al (2001) reported noticeable increases in TVC of LFS. Similarly, Charteris (1996) also reported significant increase in the standard plate count due to wide usage of dairy ingredients such as skim milk, buttermilk and SMP etc. in the formulation of table spread.…”

Edible table (bio)spread containing potentially probiotic Lactobacillus and Bifidobacterium species

“…A reduced agitation rate on the second A‐C unit was used to alter (or control) the dispersed moisture droplet size distribution in the biospread. Increasing the number of moisture droplets with a diameter > 30 µm will increase the viability of both the indigenous 74 and exogenous micro‐organisms of the aqueous phase (this study), since for nutrient‐dense emulsions such as those comprising milk proteins, microbial viability and growth is limited primarily by the available space within moisture droplets 65 …”

“…Increasing the number of moisture droplets with a diameter > 30 µm will increase the viability of both the indigenous 74 and exogenous micro-organisms of the aqueous phase (this study), since for nutrientdense emulsions such as those comprising milk proteins, microbial viability and growth is limited primarily by the available space within moisture droplets. 65 Nitrogen (OFN) addition (by means of sparging, blanketing and in-line injection) is an effective means of continually protecting lipids through to packaging. Peroxide development and flavour instability can be virtually eliminated by minimizing oxygen levels in contact with and dispersed within the product.…”

“…The processing conditions have a great influence on final product characteristics such as appearance, taste, texture, spreadability and keepability. Throughput rate, agitation rate and refrigerant temperature settings are chosen to achieve physical dispersion and entrapment of the aqueous phase in a lipid continuum as discrete moisture droplets of microscopic size, which restrict microbial growth to a small number of droplets that may be of limited nutrient composition and possess antimicrobial substances 65 . In addition, it is commonplace to pasteurize the process emulsion stream under time–temperature conditions (80°C for 1–3 min) that destroy all pathogenic and the majority of spoilage micro‐organisms.…”