Cheese Preservation Research Articles

USING OF ESSENTIAL OILS EXTRACTED FROM SOME SPICES TO EXTEND THE SHELF LIFE OF SOFT WHITE CHEECE

Essential oils of aniseed, nigella and clove were used to extend the shelf life of soft white cheese preservation at 0.05% of curd weight and to get rid of whey before salting . Having been preserved in 250 gm cans and kept for 1, 7, 14, 21, 28 days at 5 Co, cheese was analyzed regarding the ratio of total solid materials, fat and protein . Microbic content was studied by counting the total number of bacteria, coliform bacteria, lipolytic and proteolytic bacteria .Results showed no significant differences of spice on cheese chemical composition for all treatments whereas storing duration had a significant effect . Inhibiting effect of aniseed oil , nigella and clove on microflora especially the total number of bacteria, coliform bacteria, lipolytic and proteolytic bacteria during storage periods was incorporeal . It was shown that the aniseed inhibiting effect was higher than those of nigella and clove . It was also shown that there were incorporeal differences of storage periods on sensory evaluation of fresh white cheese concerning flavour and bitterness due to essential oils effect . Results showed the possibility of using essential oils as preservatives . The study managed successfully to increase the preservation duration of white soft cheese stored for 28 days whereas the control expired after 7 days . it is recommended to add aniseed oil , nigella or clove to prolong the shelf life of white soft cheese without affecting its chemical properties .

Use of allyl isothiocyanate sachet to preserve cottage cheese

AbstractCottage cheese frequently presents yeast and mould counts higher than the limit allowed by legislation. Therefore, the objective of this work was to evaluate the efficiency of an antimicrobial sachet on cheese preservation. Cottage cheese was produced according to Good Manufacturing Practices and without preservatives. The sachet was produced by the incorporation of allyl isothiocyanate (AIT). The sachets were attached to the inner surface of the lids of cups containing cheese. The cups were stored for 35 days at 10°C ± 2°C. Two control treatments were used: sachet without AIT (control 1) and packaging without sachet and without headspace (commercial form) (control 2). The efficiency of the antimicrobial sachet was evaluated by determination of yeast and mould counts. The antimicrobial sachet was effective against yeasts and moulds. Therefore, it has the potential to extend the shelf life of cheese and reduce the use of preservatives.

A combination of chitosan, coating and modified atmosphere packaging for prolonging Fior di latte cheese shelf life

In this work, the addition of chitosan into cheese making, combined with either coating or active coating (lysozyme and ethylenediamine tetraacetic acid, disodium salt) and MAP (modified atmosphere packaging) was used to prolong the shelf life of “Fior di latte” cheese. On the packaged cheese stored at 4 °C microbiological, pH, gas composition and sensory changes were monitored over an 8-day period. Results showed that the combination of chitosan, active coating and MAP improved “Fior di latte” cheese preservation by increasing the shelf life in comparison with the traditional packaging. In fact, the latter showed a very short shelf life limited to more or less 1 day, whereas the integrated approach developed in this study allowed us to obtain a significant shelf life prolongation to 5 days, most probably due to the synergic effect between the active compounds and the atmospheric conditions in the package headspace.

Active coating and modified-atmosphere packaging to extend the shelf life of Fior di Latte cheese

In this work the combination of active coating and modified-atmosphere packaging (MAP) was used to prolong the shelf life of Fior di Latte cheese. The active coating was based on sodium alginate (8% wt/vol) containing lysozyme (0.25mg/mL) and EDTA, disodium salt (Na2-EDTA, 50mM). The MAP was made up of 30% CO2, 5% O2, and 65% N2. The speed of quality loss for the Fior di Latte cheese, stored at 10°C, was assessed by monitoring pH and weight loss, as well as microbiological and sensorial changes. Results showed that the combination of active coating and MAP improved Fior di Latte cheese preservation, increasing the shelf life to more than 3 d. In addition, the substitution of brine with coating could allow us to gain a double advantage: both preserving the product quality and reducing the cost of its distribution, due to the lower weight of the package.

LISTERIA MONOCYTOGENES AND ESCHERICHIA COLI O157:H7 INHIBITION IN VITRO BY LIPOSOME‐ENCAPSULATED NISIN AND ETHYLENE DIAMINETETRAACETIC ACID

ABSTRACT Encapsulation technologies that effectively reduce antimicrobial interaction with food components or protect antimicrobial compounds from food processing measures have the potential to improve the microbiological safety of ready‐to‐eat foods. Recent application of liposomes for the preservation of cheese has spurred research into their utility in other food matrices. To ascertain the feasibility of encapsulated antimicrobial for the control of Listeria monocytogenes and Escherichia coli O157:H7 growth in a model system, nisin (5.0 and 10.0 µg/mL) and the chelator ethylene diaminetetraacetic acid were entrapped in phospholipid liposomes. While phosphatidylcholine (PC) liposomes did not produce significant inhibition of target pathogens, PC/phosphatidylglycerol 8/2 and 6/4 (mol%) produced significant inhibition of pathogens. Near‐complete inhibition of E. coli O157:H7 with liposomal antimicrobials at concentrations below those reported necessary for unencapsulated antimicrobial and chelator suggests that liposomes may represent a powerful technology for the encapsulation of antimicrobials and the control of foodborne pathogens.PRACTICAL APPLICATIONSThe activity of many antimicrobials is abolished in many food products for a variety of reasons. Interference and cross‐reactions of the antimicrobial and various food constituents, such as protein and fat, are difficult to overcome and often require large amounts of antimicrobial in order to gain significant reductions in the pathogen load in a product. Loss of solubility of some antimicrobials based on pH or ionic strength will negatively affect the antimicrobial potential of a compound like nisin. Liposome encapsulation technologies, such as that reported here, may allow for the maintenance of antimicrobial activity by protecting the antimicrobial against cross‐reactions with food components. Additionally, the liposome core represents a microenvironment which can be manipulated by the manufacturer in order to preserve optimal antimicrobial solubility and stability conditions until the time of release.

Selected Microbiological Properties of Kashar Cheese Samples Preserved with Potassium Sorbate

Kashar cheese, traditionally produced, is a popular dairy product in Turkey. Kashar cheese—a hard cheese—is frequently contaminated with mould. Potassium sorbate can be used for preservation of Kashar cheese. In this article, the effect of potassium sorbate on the microbiological characteristics of Kashar cheese was studied. It was found that the microbial counts at stored at 4 ± 0.1°C for 12 and 24 hours were not different from that of fresh milk samples. The means of total aerobic mesophilic bacteria (TAMB), lactic acid bacteria (LAB), coliforms, Staphylococcus aureus, proteolytic microorganisms, lipolytic bacteria, psychrotrophic bacteria and yeast-moulds in the cheese samples were determined as 4.3 × 107, 2.1 × 105, 3.5 × 10, 1.2 × 10, 4.5 × 105, 5.6 × 104, 1.7 × 103, and 4.8 × 104 cfu/g, respectively. The addition of potassium sorbate to Kashar cheese decreased the coliform and yeast-mould counts. The yeast and mould counts of cheese samples with added dry potassium sorbate were lower than that of fluid potassium sorbate.

ANTIBIOTIC ACTION REVEALED BY NMR

ONE OF THE OLDEST ANTIbacterials has finally been caught in the act: Using high-resolution nuclear magnetic resonance spectroscopy Dutch researchers freeze-framed the binding action of the peptide nisin with lipid II, a bacterial cell wall precursor { Nat. Struct. Mol. Biol. , published online Sept. 12, http://dx.doi.org/10.1038/nsmb 830}. Understanding nisin's binding should give drug-makers ideas for creating antibiotics to which bacteria are less likely to develop resistance. Nisin is one of a class of antibacterials called lantibiotics, and it has intrigued scientists for along time. A natural antibiotic created by some bacteria to fight others, it was first discovered in milk. It has been used as a food preservative in cheese and dairy products for about 40 years in more than 80 countries, yet resistance to the peptide is rare. The nisin-lipid II binding structure reveals why. Researchers at Utrecht University led by spectroscopy Robert Kaptein and biochemist Eefjan Breukink, took an ...

Salting and the role of salt in cheese

Salt levels in cheese range from ∼0.7% (w/w) in Swiss‐type to ∼6% (w/w) in Domiati. Salt has three major functions in cheese: it acts as a preservative, contributes directly to flavour, and is a source of dietary sodium. Together with the desired pH, water activity and redox potential, salt assists in cheese preservation by minimizing spoilage and preventing the growth of pathogens. The dietary intake of sodium in the modern western diet is generally excessive, being two to three times the level recommended for desirable physiological function (2.4 g Na, or ∼6 g NaCl per day). However, cheese generally makes a relatively small contribution to dietary sodium intake except if high quantities of high‐salt cheeses such as Domiati and feta are consumed. In addition to these functions, salt level has a major effect on cheese composition, microbial growth, enzymatic activities and biochemical changes, such as glycolysis, proteolysis, lipolysis and para‐casein hydration, that occur during ripening. Consequently, the salt level markedly influences cheese flavour and aroma, rheology and texture properties, cooking performance and, hence, overall quality. Many factors affect salt uptake and distribution in cheese and precise control of these factors is a vital part of the cheesemaking process to ensure consistent, optimum quality.

Inhibitory effect of clove oil on Listeria monocytogenes in meat and cheese

The antilisteric activity of clove oil was examined in meat and cheese at both 30°C and 7°C. At concentrations of 0·5% and 1% clove oil restricted the growth of Listeria monocytogenes in the food items at both temperatures. The inhibitory activity of clove oil was more pronounced at a concentration of 1%.Listeria counts in treated samples were 1–3 log10cfu g−1less compared to controls at different intervals during storage. The results revealed the potential of clove oil as a natural preservative in meat and cheese.

The role of olive oil in the preservation of yogurt cheese (labneh anbaris)

Small ‘balls’ of yogurt cheese (40 g 100 g‐1 total solids), derived by extracting moisture from concentrated yogurt (23% total solids), can be stored in retail outlets in the Middle East (20–25°C) under virgin olive oil for up to two years. The absence of over‐acidification appears to be due to the inhibitory effect of low pH (3.8), low available water (0.85) and salt (1.0 g 100 g‐1) on starter activity, while the anaerobic conditions created by the oil both reinforce these inhibitory factors and, additionally, prevent the growth of yeasts over the surface of the individual balls. The type of vegetable oil covering the balls was found to be unimportant, and sunflower, safflower and cottonseed oil were equally effective in preserving yogurt cheese inoculated with Kluyveromyces marxianus subsp marxianus and stored for three months at 25°C.

The levels of cadmium, nickel, manganese lead, zinc, iron, tin, copper and arsenic in the brined canned Jordanian cheese.

The levels of cadmium, nickel, manganese, lead, zinc, iron, tin, copper and arsenic in fresh sheep's milk, white brined cheese preserved in glass jars and in tin containers and their corresponding brines, salt and tin plates were determined by atomic absorption spectrophotometry. The results have been compared with those reported in recent years. Although metal levels were comparable with other investigators' data, our data shows that white brined cheese picked-up metals from tin containers and from the naturally contaminated salt, on the contrary brined cheese in preserved glass jars showed lower levels of metals. We recommend a purified salt for brine preparation and glass jars for white cheese preservation in order to minimize cheese contamination with metals from tin cans and salt.

The preservation of cottage cheese by an activated lactoperoxidase system

An activated lactoperoxidase system (LP-S) consisting of the addition to chill stored cottage cheese of 1.2 × 104 units kg−1 lactoperoxidase (LP) and 84 mg kg−1 potassium thiocyanate was activated with a glucose/glucose oxidase system and additionally in a separate experiment with 376 mg kg−1 urea peroxide. The LP-S was found in all cases to be lethal to Escherichia coli and Salmonella typhimurium inoculated into the cottage cheese. The LP-S treatment did not affect the pH or sensory characteristics of the cheese.

Preservation of Cheese and Plain Yogurt by Low-dose Irradiation

Irradiation preservation of Turkish kashar cheese and plain yogurt was studied using very low doses of Co-60 radiation. No side effects were observed below 0.15 Mrad. The number of bacteria killed was directly related to total dose up to 0.02 Mrad, then the effectiveness of the dose decreased. Coating cheese samples with a sorbic acid solution helped in reducing the number of bacteria by about 10–12% in irradiated samples. The shelf-life of irradiated samples stored at refrigerator temperature was almost the same as that of ones coated with sorbic acid but stored at room temperature. Mold formation in irradiated samples took three to four times longer than in nonirradiated ones. With plain yogurt the effect of total dose seemed to be the same as in cheese. Irradiation increased the shelf-life of yogurt three- to four-fold. Preservation by irradiation combined with refrigeration increased the shelf-life about five-fold.

Preservation of cheese with combined use of gamma-rays and sorbic acid

Preservation of cheese with combined use of gamma-rays and sorbic acid