DE LA INTEGRACIÓN Y ESTRUCTURA DEL PRESUPUESTO DE EGRESOS

Cheese preservation is one of the most common applications of sorbates. In the United States, federal standards of identity permit the use of sorbates as preservatives in more than 40 types of cheese, cheese spreads, and cheese food [21 C.F.R. Part 133 (2001)].

TABLE 3.3

Common Applications of Sorbates as Antimicrobial Agents

Products Levels (%)

Dairy products: aged cheeses, processed cheeses, cottage cheese, cheese spreads, cheese dips, sour cream, yogurt

0.05–0.03 Bakery products: cakes, cake mixes, pies, fillings, mixes, icings, fudges, toppings, doughnuts 0.03–0.30 Vegetable products: fermented, pickles, olives, relishes, fresh salads 0.02–0.20 Fruit products: dried fruit, jams, jellies, juices, fruit salads, syrups, purees, concentrates 0.02–0.25 Beverages: still wines, carbonated and noncarbonated beverages, fruit drinks, low-calorie drinks 0.02–0.10 Food emulsions: mayonnaise, margarine, salad dressings 0.05–0.10 Meat and fish products: smoked and salted fish, dry sausages 0.05–0.30 Miscellaneous: dry sausage casings, semimoist pet foods, confectionary 0.05–0.30

Kivanç (1992) found that Penicillium was the major genus found on cheddar cheese, Swiss cheese, and domestic and imported cheeses. Sorbates are widely used in preserving cheese owing to the susceptibility of all types of cheese to microbial deterioration, especially surface mold growth during storage, aging, and distribution; the high activity of sorbates against molds; and the improved action of sorbates at high pH values compared to other common preservatives (Lück, 1976, 1980; Sofos and Busta, 1981). In these applications sorbates not only prevent cheese spoilage by mold, but they also protect human health by preventing the formation of toxic mold metabolites (myc- otoxins). It is obvious, however, that sorbates should not be used in mold-ripened cheeses, such as Roquefort or blue cheese and Camembert cheese, in which they can interfere with the desirable molds involved in the manufacture of these cheeses.

Sorbate application, in general, is limited to the surface of cheese, where mold development usually occurs. In certain products, however (e.g., cottage cheese), sorbic acid may be incorporated into the cheese curd. The method of application varies with the type of cheese; preservation objectives; available facilities and equipment; and regulations, which may vary among countries (Lück, 1976, 1980). Addition of sorbate does not significantly affect the organoleptic properties of mozzarella cheese; however, depending on the technique used to treat the cheese (i.e., dipping or in brine salting), there may develop a slight objectionable flavor (Aly, 1996). For application on

TABLE 3.4

Methods of Application of Sorbates

Methods Products

Solution (%)

Application Level (%) Immersion Dairy: provolone, Siciliano, Caciocarallo, pasta filata,

Edam, Muenster, Gouda Dry sausage or casings

20–40 2.5–10

0.1–0.3 0.05–0.3

Spraying Dairy: Swiss, Gruyere, Emmentaler 20–40 0.1–0.3

Immersion or spraying

Dairy: cheddar, Colby, Monterey Jack, blue, mozzarella Dried fruits: Prunes

Raisins Figs

Smoked and salted fish

20–40 2.5–5 5 2.5–5 5 0.01–0.3 0.02–0.06 0.25 0.05–0.1 0.05–0.15 Dry mixing Bakery: Cheesecake

Angel food cake Fruitcake Cake mixes Doughnut mixes Pie crust dough

0.1–0.3 0.03–0.06 0.1–0.4 0.05–0.1 0.05–0.1 0.05–0.1 Direct addition Dairy: processed cheese, spreads

Cottage cheese

Bakery: icings, fillings, toppings, fudges

Vegetables: fresh salads (potato, vegetable, slaw, pickles, relishes, olives, sauerkraut)

Fruits: syrups, beverages, drinks Still wines

Other: Margarine Semimoist pet food

0.1–0.2 0.05–0.075 0.05–0.1 0.05–0.15 0.05–0.1 0.025–0.075 0.02–0.04 0.05–0.1 0.1–0.3 Dry mixing or direct addition

Bakery: pound cake Devil’s food cake Chocolate cake

0.075–0.15 0.3 0.1–0.3

Sorbic Acid and Sorbates 63

the surface of the cheese, one of the following procedures may be followed: (1) potassium sorbate in solution or in a brine, which can be used to dip, spray, or wash; (2) a sorbic acid powder for dusting; and (3) sorbic acid, potassium, or calcium sorbate impregnated into the packaging material or other coatings (e.g., wax) used in cheese storage and marketing (Han et al., 1998; Sofos, 1989; Weng and Chen, 1997). Treatment of mozzarella cheese with potassium sorbate in the kneading water or brine may be more effective than dipping (Aly, 1996). Amounts of sorbic acid permitted and applied in cheese preservation range from 0.05% to 0.30% (Lück, 1980; Sofos and Busta, 1981). Levels of 0.05% to 0.07% sorbic acid are generally used in direct addition to cheese. Concentrations applied to cheese surfaces range from 0.1 to 0.3 g/dm2_{, whereas when applied to}

packaging films, amounts of 2 to 4 g/m2 _{are used (Lück, 1980). The appearance of Penicillium}

verrucosum var. cyclopium mycelia and spores isolated from cheeses and inoculated as suspensions into YES broth containing 1000 µg of potassium sorbate/ml was not detected at 5°C, 15°C, and 25°C after 30 days (Kivanç, 1992). Addition of potassium sorbate (≤6%) to mozzarella cheese inhibited growth of Streptococcus salivarius var. thermophilus and Lactobacillus delbrueckii var. bulgaricus, and was especially effective against mold and yeast contamination by Penicillium roqueforti and Mucor miehi, respectively (Aly, 1996). Inclusion of sorbic acid in cottage cheese was effective as a preservative but not against L. monocytogenes (Piccinin and Shelef, 1995); however, at the relatively high level of 1%, potassium sorbate inhibited L. monocytogenes survival in two commercial cheese brines (Larson et al., 1999). In another study, potassium sorbate (0.3%) or sodium benzoate (0.3%) showed a significant effect in delaying growth of E. coli O157:H7 in queso fresco, soft cheese (Kasrazadeh and Genigeorgis, 1995). Milk acidification to pH 6.0 with hydrochloric, acetic, or propionic acid significantly increased the effectiveness of potassium sorbate, especially at lower (≤6.6°C) temperatures (Kasrazadeh and Genigeorgis, 1994). Growth of Salmo- nella in soft cheese was inhibited if the cheese was prepared from milk that was acidified with propionic acid to pH 5.9, potassium sorbate was added to the cheese (pH 6.0) at levels of ≥0.3%, and the cheese was stored at ≤30°C (Kasrazadeh and Genigeorgis, 1994).

Absorption of the compound from the surface into the cheese is dependent on the porosity of the surface and the amount and distribution of fat in the cheese. Calcium sorbate may be preferred in cheese preservation over other forms of sorbate owing to its solubility properties. The compound is insoluble in fat and only slightly soluble in water. Therefore, when applied to the surface of hard, ripened cheeses, most of the preservative remains on the surface of the cheese without migrating inside the cheese or dissolving in the water on the shelves during the long maturation period of these cheeses (Lück, 1976). In addition to reducing cheese spoilage and the possibility of aflatoxin formation, use of sorbates in aged cheeses also reduces labor and other costs through reduction of the need for cheese washing and trimming. Furthermore, addition of potassium sorbate may increase the meltability and improve the fat leakage of certain cheeses (Aly, 1996).

In labaneh (a yogurt product) produced under strict hygienic processing measures and effec- tively chilled, initial numbers of yeasts were low and relatively low concentrations of potassium sorbate and sodium benzoate (<150 and <250 mg/kg, respectively) extended the shelf life by 14 days. Labaneh with higher initial yeast counts needed higher concentrations of preservative (>300 and >400 mg/kg for K-sorbate and Na-benzoate, respectively) to maintain stability when kept at 5°C for 7 or 14 days. These concentrations are in agreement with use of these preservatives in other dairy products, such as cottage cheese and yogurt (Mihyar et al., 1997).