KEY FACTORS AFFECTING THE SURVIVAL AND GROWTH OF PATHOGEN

KEY FACTORS AFFECTING THE SURVIVAL AND GROWTH OF PATHOGEN

Pathogen survival and growth on food-produce is influenced by a number of interdependent factors, principally storage temperafture, product type/combinations, minimal processing operations (e.g. slicing, shredding, washing and decontamination treatments), mild technologies, package atmosphere and competition from the natural microflora present on food-produce.

First, each product type has an exclusive combination of compositional and physical characteristics and will have specific growing, harvesting and processing practices, and storage conditions; pathogen growth on food-produce varies significantly with the type of product (Wells and Butterfield 1997).

Storage of food-produce at adequate refrigeration temperatures is probably the single most important factor affecting survival and growth of pathogens.

Washing with tap water removes soil and other debris, some of the surface micro flora, cell contents and nutrients released throughout slicing that support growth of microorganisms (Tournas 2005).

However, while washing in tap water removes bacteria from exposed surfaces, substantial numbers will remain in hollows at the connection of epidermal cells and in folds in the epidermis (FDA 2000).

In addition, due to the re-use of wash water in industry, washing may result in bacterial enrichment and cross-contamination of products rather than decontamination.

A variety of antimicrobial wash solutions have been used to diminish populations of microorganisms on fresh produce. Chlorine added to water as a solid, liquid or gas is the most frequently used disinfectant for fresh fruits and vegetables; however, a wide variety of other disinfectants, including acidic electrolysed water, peroxyacetic acid, chlorine dioxide, hydrogen peroxide, organic acids, trisodium phosphate and ozone have been also evaluated (Ibenyassine 2007).

Natural antimicrobials from edible plants such as oilseeds, herbs, spices, fruit and vegetables, have been studied for their potential as possible replacements for chemical additives because of their safety for human consumption and broad acceptance from consumers (Viswanathan and Kaur 2001).

Phenolic compounds present in plant essential oils (EOs) have been shown to possess antimicrobial activity and some are classified as generally recognised as safe (GRAS), and consequently may be useful to prevent post-harvest growth of spoilage and pathogenic bacteria (Viswanathan and Kaur 2001)