Deli Dining

By Donna Berry, Contributing Editor

A mere 10 years ago, many consumers never would have thought of going to the supermarket for a take-out meal. Times have changed. Store redesigns, innovative display cases and self-service bars, and creative, often chef-inspired, ready-to-eat (RTE) foods have made the supermarket deli a destination for salads, sandwiches, soups and more.

A contributing factor to the rise in popularity of deli foods is that many consumers believe they are fresher, less-processed and homemade. These attributes challenge product designers with formulating convenience foods that maintain safety and quality throughout product shelf life, yet still live up to consumer perception.

The problem is that a product full of preservatives with a 90-day shelf life is hardly fresh," says Jan Payne, business development manager, Purac, Lincolnshire, IL. Thus, challenges in formulating deli foods include sustaining freshness and maintaining homemade taste all through the use of consumer-friendly ingredients. The fact is consumers expect the products purchased in the deli department to have a shorter shelf life, but at the same time they expect fresher products than the processed food in the rest of the supermarket."

Formulators apparently are taking on the challenge, as todays deli departments are booming as supermarkets aggressively compete with fast-food drive-thrus, quick-service meals-to-go and restaurant take-out for their share of dining dollars. Supermarket-prepared foods not only attract out-to-lunch diners looking for an alternative to the traditional burger and fries, they also appeal to consumers who are looking to save money on eating out while saving time over cooking dinner from scratch.

Keeping quality

Food manufacturers are responding by offering an increased variety of RTE foods that require little or no preparation by the deli operator. To ensure shelf life, formulators must consider that refrigerated deli case products are sliced or dished out many times during the course of the day, so they experience fluctuations in temperatures and exposure to the environment. Cooked foods ranging from meats to sides to soups, which are held under constant heat, come with their own set of unique shelf-life hurdles.

The shelf-life challenges of so-called fresh deli foods depend on a variety of factors, including the quality of the raw ingredients, and intrinsic and extrinsic parameters of the finished product," says Jerry Erdmann, manager, food protection, Danisco USA, Inc., New Century, KS. This is especially true for products that do not receive a further kill step after assembly, such as deli salads. For example, spices and fresh vegetables may contribute to a higher initial microbial load in deli-salad products. This higher microbial load on the spices can be reduced by using an intervention, such as a steam treatment, to eliminate vegetative cells. Additionally, fresh vegetables should be used early in their shelf life to avoid long storage times under refrigerated conditions where spoilage microbes can continue to exhibit slow growth. The use of individually quick-frozen (IQF) vegetables may contribute less to the initial microbial load when compared to fresh vegetables, because the storage time under refrigerated conditions can be reduced or eliminated."

Various parameters related to the finished deli product can improve its stability. For example, proper refrigerated shipping and storage conditions, ideally less than 40°F, will slow microbial growth and oxidation," says Erdmann. In general, decreasing the water activity and pH of the finished product can also slow or reduce the growth of spoilage microbes. With this decrease in pH, it also makes the preservative or antimicrobial system more effective."

Safety first

Even more important than slowing or reducing the growth of spoilage microbes are measures to prevent contamination, particularly by Listeria monocytogenes, which, if consumed, can cause the serious human illness listeriosis. Cooking kills pathogens such as Listeria, but many RTE deli foods are not further-processed prior to consumption. These foods are particularly susceptible to contamination by Listeria, as it is present everywhere, and the open-air environment that many of these products reside in is an invitation to contamination. Each time a deli product is handled after it has been cooked, whether for cutting, slicing, portioning or wrapping, it can become contaminated. Further, unlike most other pathogens, Listeria multiplies at refrigerated temperatures. Thus, the cool, often moist, conditions found in the service deli case are the perfect environment for Listeria growth.

Even though many people are exposed to Listeria, the incidence rate of foodborne listeriosis is low. However, for vulnerable individuals, such as the elderly, pregnant woman and those with suppressed immune systems, listeriosis can be fatal. Unfortunately, unlike spoilage microbial growth, which can be detected visually or by off odors, Listeria contamination typically goes undetected until too late.

According to FSIS Risk Assessment for Listeria monocytogenes in Deli Meats" (May 2003), deli meats were identified as a very high risk food, while deli-type salads were moderate risk. Interventions that prevent or minimize growth of Listeria are important control strategies. The two key variables that affect Listeria growth in food are water activity and pH. For example, a pH of less than 4.4, or a water activity of less than 0.92, can promote microbiological safety and stability in many RTE foods, according to the assessment. Many ingredients can lower pH and reduce water activity. For example, deli salads made with acidifiers, such as lemon juice, vinegar or citric acid, might maintain a low enough pH to prevent Listeria growth.

Antimicrobial-plus

Listeria and oxidative rancidity are two of the greatest challenges food companies face in delivering deli foods that look great, taste delicious, and remain safe and fresh longer," says Betsy Blades, technical marketing manager, Kemin Industries, Des Moines, IA.

A number of ingredients assist in both of these efforts. For example, the active chemicals found in rosemary extract function not only as antimicrobials, but they also have antioxidant properties. Specifically, rosemary extract contains phenolic compounds that retard oxidation, making them effective inhibitors of the development of warmed-over flavor in precooked meat products. Certain rosemary compounds, such as alpha-pinene, camphor and verbenone demonstrate antimicrobial activity.

Deli-case meats can benefit from the addition of rosemary extract, which is an alternative to chemical preservatives for oxidation management," says Tom Jones, applied technology manager, Kalsec, Inc., Kalamazoo, MI. Rosemary extract can simply be declared as natural flavor."

Blades adds: Rosemary extract can be used in prepared-meal products like meatballs and precooked chicken to prevent the warmed-over flavors that occur when these food items are sitting in the deli for an extended period of time. Rosemary and green-tea extract (another known natural antioxidant) can be an effective solution in maintaining flavor stability for mayonnaise-based dressings used in deli salads by delaying oxidative rancidity. Propionic-acid-based ingredients are also an option for a variety of deli food items, because the acid inhibits the growth of bacteria, extending product shelf life."

Gene Brotsky, senior technical services director, Innophos Inc., Cranbury, NJ, says: Tripoly- and pyro-polyphosphates are effective iron chelators that inhibit oxidation, especially in precooked meats, and avoid warmed-over and rancid flavors. The same phosphates enhance moisture retention in processed meats by solubilizing structural proteins.

Although not listed as preservatives, phosphates have been shown in the scientific literature to affect preservative activity by chelating minerals essential to microbial growth," adds Brotsky. The industry recognizes, for example, that cheeses made with phosphate emulsifiers obtain longer shelf life than those made with citrates or other emulsifiers."

Clean-label extensions

Even though many of the RTE foods purchased at the deli do not currently come with required ingredient statements or Nutrition Facts, the wholesome perception of the deli should motivate formulators to pursue clean-label ingredients.

Certain standards should be followed, and this includes using ingredients consumers perceive as clean and natural," says Payne. Formulators should take the high road and select the more-natural solutions to ensure quality and safety through shelf life.

Formulators today have many options that meet consumers demands for cleaner labeling, while also adding additional microbial hurdles," Payne continues. For example, fermentates provide safety, as well as quality, furnishing the consumer with the assurance that their food is safe and wholesome. Fermentates can further enhance natural flavors present in many items, such as deli meats and wet salads, so artificial flavors are not required. Depending upon the application, fermentates often allow for a reduction in sodium. An additional benefit is that some fermentates are good humectants, as they contain hygroscopic substances such as lactic acid that serve to form bonds with water molecules. This can also aid in keeping the foodstuff moist for a longer period of time."

Managing water activity

Another shelf-life challenge fresh deli items encounter is moisture retention," says Monica Prendergast, senior food scientist, Gum Technology Corp., Tucson, AZ. Prepared salads, meals, soups and dressings can lose moisture if not stabilized well, giving the product a negative appearance and possibly slowing down the sales of these items.

This can easily be corrected with minor adjustments or addition of hydrocolloids," Prendergast continues. Certain hydrocolloids and blends of hydrocolloids ensure that the products withstand time and temperature adjustments that commonly occur in the deli case. For example, xanthan and arabic tend to be a good combo in salad dressings, while carrageenan and tara blendsformulated to keep the cost and usage level downcan help with sauces, soups and other dairy-based items. Often, gums can create pseudo, thin gels that will prevent the moisture from leaving the systems, while others just organize the moisture."

Moisture management impacts viscosity, which is one of the biggest issues impacting the quality of RTE soups. Such soups are typically held at 160°F or higher, which is too hot to eat, but also too hot for microbial growth. These soups must maintain integrity during the entire day," says Dan Putnam, technical manager, Grain Processing Corp., Muscatine, IA. Many viscosifiers will fail over time. Dual-modified starches, which combine cross-linking and substitution modifications, can be used to develop the initial viscosity in the soup at the point of manufacture. Oftentimes, these soups go from kettle to plastic bag to freezer. At the supermarket, the soups are heated for serving. The dual-modified starches maintain the same viscosity through all of this, and over the long period of reheating time."

Erdmann says, It is important to keep in mind the best way to ensure shelf life of deli foods is to build multiple hurdles into a product, such as managing pH and water activity, and adding antimicrobials."

After all, even though convenience and freshness are the driving factors of increased deli business, one food-safety mishap can cripple future sales.

Donna Berry, president of Chicago-based Dairy & Food Communications, Inc., a network of professionals in business-to-business technical and trade communications, has been writing about product development and marketing for 13 years. Prior to that, she worked for Kraft Foods in the natural-cheese division. She has a B.S. in food science from the University of Illinois in Urbana-Champaign. She can be reached at [email protected].

Deli-Sales Snapshot

More than two-thirds of grocery stores report an uptick in sales of supermarket-prepared foods, according to The Food Retail Industry Speaks, 2011," a research report from the Food Marketing Institute, Arlington, VA. More than 60% have added meal solutions to the lineup, and nearly 70% report an increase in ready-to-eat foods from the service and self-service deli departments.