Newly Developed Italian Cheeses Reduce Spoilage Concerns in Salad Dressings

Background

The use of Italian cheeses in salad dressings is a very common method employed to create specific, intense flavor profiles and to provide functional benefits. Formulators of other cold filled applications, such as mayonnaise and sauces, have also at times capitalized on the benefits of Italian cheese. However, it is very important that the selected cheese is ‘microbiologically safe’ (i.e. free or very low in gas-forming spoilage organisms) especially for the non-heat treated applications, such as salad dressings and sauces. The spoilage organisms most commonly encountered in these types of applications are yeast, molds and heterofermentative lactobacilli (1). Problems arising from the contamination and subsequent growth caused by these spoilage organisms are emulsion separation, syneresis, off-flavor development and gas production. Excessive gas production can eventually lead to the bulging and ‘blowing-out’ of containers. Therefore, the selection of ingredients, including cheese, becomes a critical step in the quality and shelf life of cold filled products. Since heat is not employed in cold fill applications, it is the acidic environment (pH <4.1) and low water activity which are relied upon for product preservation. Many times, formulators will attempt to lessen harsh acidic flavor notes in salad dressing by reducing the level of acidulants, in which case the selection of the added cheese ingredients becomes even more critical. The pH value of a particular salad dressing can play a large role in determining the degree of growth of a contaminating gas forming organism (refer to Fig. 1.) and thus product shelf life.

Customized Cheeses Add Flavor and Functionality

Hard grating Italian cheese such as Parmesan, Romano and Asiago provide complex flavor profiles in application ranging from aromatic dairy type topnotes, to sweet, nutty middle ground notes to savory background notes. Additionally, the Romano-type cheeses also deliver bold, sharp and piquant background notes. It is important that the flavor notes provided by the Italian cheeses are complex and intense enough to overcome the acidity level found in salad dressings and other cold filled application products. The flavors provided by these cheeses can also complement salad dressings, such as in the case of a Caesar dressing. Finished product flavor profiles can also be affected by the type of cheese added (fresh grated vs. dry grated). The fresh grated forms, ranging from 32-35% moisture for the Italian grating cheeses will have the balanced and complex flavor profiles mentioned previously. The dry grated counterparts of these cheeses (moisture ranging from 16-20%) will tend to have a more one-dimensional, less balanced flavor profile. The dry grated cheeses are typically prepared by placing the fresh grated cheese into a hot-air dryer and driving off moisture until the desired moisture is attained. This heating step, that drives out moisture also causes many of the delicate top notes to volatilize and dissipate into the atmosphere. The loss of aromatic flavor notes is even more extreme in cheese powders that are typically dried to moisture levels of 3-5%. The hard grating Italian cheeses can also provide important functional characteristics such as particle identity and an appealing contrasting mouthfeel to an otherwise smooth textured salad dressing. Cheeses, having a structured casein network and high fat content can also provide a creamy, velvety mouthfeel. The particle size of the grated or shredded cheese and degree of solublization can also affect finished product texture and mouthfeel.

The Spoilage Organisms

In general, salad dressings are composed of a vegetable oil and a low pH salt containing water phase. Sufficient cooking to sterilize salad dressings would destroy their physical integrity, thus preservation usually depends on the addition of acidulants such as vine