The food safety study of hummus is in two parts: the first focus, addresses food safety issues related to product formulation whiles the second focus is a study targeted at evaluating the impact of consumer knowledge and food handling practices in food safety. The first part of this study was a challenge study to evaluate the shelf life of four industrially produced refrigerated hummus formulations. The introduction of new products and the expansion of existing product lines, may lead to unforeseen food quality and safety challenges for food industries, especially in recent times where foods that were once indigenous to a particular society, is now being eaten by a wide range of people. This new trend is a result of increased global migration, leading to increased food diversity in communities, which are becoming more cosmopolitan. This shift in the diversity of populations is constantly impacting and driving continually changing trends in the food industry. As consumers continue to demand ready to eat, fresh and safe traditional foods that can be purchased in supermarkets, it has become necessary to prepare foods that were once made traditionally on a small scale, industrially for commercial and retail purposes. Food industries meet this demand, both on a small and large scale because of improvements in the processing, preservation and packaging of many traditional products that have been achieved, despite the rudimentary processing of traditional foods due to the use of simple equipments, lower energy input, and the availability of resources.
Preliminary steps of the hazard analysis critical control point system:
Hazard analysis critical control point system requires some preliminary steps to be taken into consideration before the implementation of the seven principles. Determination of product properties, process flow charts, plant layout and process descriptions as preliminary steps will be very helpful in the HACCP implementation.
Raw materials, and ingredients, were specified for the identification and the assessment of food safety hazards including biological, chemical and physical characteristics.
Traditionally hummus was cooked and consumed domestically as an appetizer together with Arabic bread, but in recent times it is also being produced and packaged in 100 g to 300 g “press-to-seal” plastic packages for sale commercially. Hummus traditionally a widely eaten Middle Eastern delicacy, served as a relatively cheap source of protein in the diet, but in recent times though, hummus is being eaten globally.
Preparation and serving of hummus:
Hummus is usually made using these ingredients: chickpeas (Cicer arietinum L), tahina (an oily viscous liquid derived from milled dehulled roasted white sesame seeds), garlic, lemon juice or citric acid and salt. Traditionally the chickpeas were steeped overnight, and then softened by boiling with sodium bicarbonate. The soft cooked chickpeas are then cooled and then mixed with tahina (tahini) and other ingredients (garlic, lemon juice or citric acid and salt) to obtain the basic smooth hummus mix. Hummus traditionally is normally served off plates or dishes but in recent times commercially produced hummus may be served straight out of the packaging or tub. Often hummus is served with a topping of a special dressing made of lemon juice, ground pungent green capsicum and garlic, as well as olive oil and, occasionally, chopped parsley. The average nutrient content of a 100 g edible serving of hummus consists of 49.5, 9.6 and 19.7 g of water, protein and fat, respectively and 300 Kcal energy.
Food Safety Concerns; hummus spoilage:
General Microbial Spoilage
A consumer’s perception of the occurrence of visible food spoilage which makes foods unacceptable, according to Day, 1999, is when the visible characteristics of the foods such as the appearance, flavour, smell and texture changes. The most widely used and effective preservation techniques, currently used to prevent or delay food spoilage include temperature, pH, and water activity (aw) reduction, as well as heat application. Food preservation is highly improved when techniques are used to alter these factors to produce a synergistic effect. Microbial spoilage of chilled foods is very diverse and may be a result of the type of microorganism present, the nature of the food substrate and the effect of temperature on the food, subsequently different microorganisms may adapt to changes in condition and nutrient levels in order to survive in the foods.
Spoilage by Yeast and Molds
The survival, growth and metabolism of yeast and molds in ecosystems such as food, are regulated by interconnected strain and species interactions, which may involve interactions with bacteria cells and other fungi. Fungal infestations are of major concern in the food and agricultural industry globally and may start right in the field, particularly in the tropics where humidity is high (generally > 80%) and hence mold growth is favoured This occurrence may lead to very huge economic losses, because most food products either processed or fresh e.g., fresh fruits, berries, marmalades, juices, 6 cereals and grains, are susceptible to yeast and mold contamination and growth after harvesting With the recent surge of product development in the food industry coupled with food safety concerns, associated with opportunistic infections involving yeast and molds, as well as other adverse effects of yeast infection in humans, interest in understanding the survival and growth of yeast in foods has been heightened.
Effect of Temperature on Food Spoilage
Food spoilage is influenced by temperature because most biochemical activities are either slowed down at reduced temperatures or speeded up at increased temperatures. Elevated temperatures enhance food spoilage, by altering the biological mechanisms in the food, which may lead to enzyme or protein denaturation and a subsequent increase in solute concentration, which may subsequently cause changes in pH and ionic strength of the medium (food) Subsequently the application of reduced temperatures (refrigeration) during food storage has become a widely accepted method of storing minimally processed foods as a means of controlling and decreasing the progression of biochemical and microbial degradation in the food. Low temperature is effective in preserving chilled foods because it either totally inhibits the growth of microorganisms in the foods and or reduces subsequent growth of these microbes by prolonging the lag phase Day, 1999, observed that at reduced temperatures, approaching the least possible growth temperature for a microorganism, the vulnerability of the microorganism to the effects of the preservative attributes of the food like acidity (pH) and water activity (aw) is enhanced. Food safety in industrial production takes precedence over other food quality issues in the production of chilled 7 foods and foods in general, this is important because although chilled foods may appear wholesome it may still contain large numbers of pathogens and toxins.
Effect of pH on Food Spoilage (Low pH and Weak Acid Synergy)
The pH of the food influences the microbial, as well as enzymatic activity of the food and subsequently influences the rate and type of food spoilage observed for a particular food. An extensively used combination preservation technique is to enhance the effect of an antimicrobial acid within the food by lowering the pH of the food. Many useful food preservatives fall into this category and thus provide the synergistic effect that produces a low pH, mild acid environment (food), capable of inhibiting some microbial growth in the food. There are two modes of action for the functionality of these antimicrobial acids which include inorganic preservatives, sulphite, nitrite and the weak organic acids. As the lipophilicity of organic acids increase, its effectiveness as a preservative is enhanced; e.g., an increasing order of lipophilicity and subsequently effectiveness is: acetic, propionic, sorbic, benzoic. The second important aspect of the mode of operation of these acids, are their dissociation constants, their undissipated forms are the most lipophilic and are the ones that easily diffuse through the membrane of the microbe, this is influenced by the pH value and the dissociation constant (pK) and together these determine the amount of the undissipated acid remaining The scope of pK values of the usual weak organic acid preservatives span 4.2 for benzoic to 4.87 for propionic acid, hence at higher pH values their activity is greatly diminished. In the microbial cell cytoplasm these undissipated acids dissociate, producing hydrogen ions and their accompanying anions 8 because most microbes in foods maintain an internal pH higher than that of their environment Additional energy is required by the cell to export the additional hydrogen ions produced through the above mechanism. Hence in an attempt to maintain an elevated internal pH, cell growth is limited, till the required additional energy is obtained, to enable the pH of the cytoplasm to finally decline to unfavorably low levels limiting progressive cell growth. Gould et al., 1996, thus concluded that the simultaneous decrease of pH plus the availability of weak acid preservatives in a food, will lead to higher energy requirements by the microbial cells in the food and subsequently limit the effective generation of ATP by these cells, resulting in their growth retardation and a subsequent decline in microbial food spoilage.
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