Aaron L. Brody

When, in the course of IFT events, it becomes necessary to deliver culinary quality food to target consumers—as we all are—the teaming of chefs and food scientists and technologists becomes a necessary marriage. Chefs, as we all know— or will soon, as they permeate our “turf ” and we theirs—generate high-quality food products they refer to as “gold standards.” Translating these gold standards created in their—and our—laboratory kitchens into food products that can be mass produced and shipped over long distances over long periods of time and still arrive on the consumer’s table with as much of the gold standard quality remaining as possible requires overcoming many challenges.

Examples of products in which application of hurdle technologies results in extended shelf life include, clockwise from top left, jam (controlled water activity of product plus low-moisture-permeability package plus natural preservative to retard mild surface microbial growth); pasta (water activity, clean fill, reduced oxygen, and chilling integrated into a single barrier package); lunch kits (water activity control, modified atmosphere, refrigerated distribution, and barrier packaging); and salsa (clean fill, pH control, ultra-high pressure, oxygen control, and chilled distribution).

Food Deterioration and Preservation
A basic premise is that food deteriorates. Food scientists and technologists know that almost all food changes begin immediately after preparation, whether on the way from the chef ’s kitchen to the dining table or from the food scientist’s laboratory to process operations and distribution to the consumer’s dining region, whether at home or in a white-tablecloth restaurant or in a fast-food outlet, etc.

Scaling-up from the kitchen or laboratory is an exacting exercise demanded of that industrial branch of food technology often referred to as food engineering or food process engineering. And carrying the food and its quality—the chef ’s gold standard—to the consumer safely integrates the product, process, packaging, and distribution channel to the consumer. In simple terms, effective technology must be interjected into the chef ’s output to translate the food innovation into consumer consumption.

To preserve the chef ’s gold standard as it proceeds from the kitchen or factory through the distribution chain to the ultimate consumer, we could apply triedand- true mainstream preservation technologies such as drying and canning, or even incorporation of chemicals as mechanisms. Applying an adaptation of the Heisenberg theory, however, these processes alter the food product radically and thus are aimed at providing a different quality standard, perhaps a quite acceptable “stainless steel,” but hardly “gold.” Freezing has its “silver” level merits but arguably might not be the optimum vehicle to carry the best food quality to the ultimate market. Some might advocate delivering the food hot, but the shelf life at 140°F is altogether too brief, suitable perhaps for immediate restaurant service, but hardly for real food for real people at home, in the office, or in an automobile. And hot is not recommended for most salads, many desserts, and many other foods intended for consumption chilled.

To deliver gold standard, and perhaps eventually “platinum” standard, food products to market, enhanced chilling meets almost all of the requirements-by little changing the product as a consequence of the preservation process itself. Enhanced chilling is more often described as hurdle or combination technology-or, in our own parlance, holistic hurdle-to ensure that all the components contribute meaningfully to serve up truly great food products.

Holistic hurdle technology is the integration of several different technologies in synergy with each other to prolong the safe retention of as much of the initial quality as the chef invented into the product. The objective is to offer to the target consumer food that is as good as if the chef had instantly customized it to order on site, but without having the chef on premises.

If the arguable assumption is that combined technologies using the chilled distribution channel is the optimum route to having a virtual chef preparing the consumer’s breakfast omelet, lunch panetta sandwich, Maine lobster thermidor dinner, and vegetable martini snack, the next question is how.

Hurdle Technologies
Hurdle technologies have been with us for decades, although not designated as such until the 1980s. Canning, for example, is the assembly of ingredients under reduced oxygen into a hermetically sealed can with associated heating and cooling cycles to render the contents statistically sterile for ambient-temperature distribution. It involves the application of blanching, blending with liquid, removing oxygen, placing in barrier packaging, hermetic sealing, heating, and cooling—a combination of multiple technologies which together provide for a safe quality level throughout the distribution channel. Modified-atmosphere packaging requires the clean preparation of product, reduction in temperature, clean filling into special high- or low-gas-permeability packaging, removal of oxygen (usually), elevation of carbon dioxide level, sealing, and maintaining the temperature at or near 32°F throughout distribution. The consumer’s contribution to this combination of microbiological suppression, enzymatic control, and biochemical retardation is to open the package and reheat it in a conventional or microwave oven—not always an easy procedure—remove the food product, and enjoy the product from the now-open package or even on a plate.

Hurdle technologies thus are neither new nor daunting: they represent the application of mostly well-known technologies in reduced “doses” to interact synergistically to control safety, sensory quality retention, and nutritional values. This is easy enough to recite but more complex in real-life application because most of us do not know the quantitative contributions of each hurdle in concert with each other. Thus, operators tend to overcompensate in what they are comfortable with and lightly dismiss that which challenges them. How often do the back-room supermarket home-meal-replacement folks prepare a delicious dish and, after packaging it in a PVC-film-wrapped, black expanded-polystyrene tray, try to chill it to below the officially mandated 41°F in a reach-in cooler bulging with the morning’s hot output? The easy way out for the retail grocer’s food preparer is to apply a one-day expiration date on the package for display and discard the product tomorrow if it is not sold today. Or the hardly unfamiliar situation in which the factory-prepared dish—using the chef ’s recipe scaled-up with the usual modifications to accommodate to processing— still warm from preparation is placed on a microwavable polypropylene tray, wrapped in a paperboard sleeve, cased in corrugated fiberboard, palletized, and rolled into a room at about 50°F, expecting the temperature to magically decrease to 40°F in a finite time before entering the often-abusive distribution channel.

With enhancement, chilled shelf life of many weeks is possible, with the consumer eating the resulting product that is not too dissimilar from the chef ’s vision. Without the crucial application of the enhancements-hurdles-the expiration dates must be foreshortened, leading to short runs, deep discounts, discards, marginal organoleptic quality, and, in the extreme, potentially hazardous microbiological growth.

Hurdle technologies, especially those which function effectively under the holistic umbrella, encompass a variety of technologies. They include, among others, pH control, water activity reduction, pasteurization-mild heat whose objectives might include enzyme destruction and reduction of microbiological load-, incorporation of natural antioxidants such as ascorbic acid, incorporation of natural antimicrobials, ultra-clean/aseptic type handling and filling, rapid reduction of product temperature, maintenance of temperature throughout distribution, reduction of oxygen in and around the product, elevation of carbon dioxide in and around the product, gas-barrier packaging to maintain the internal gas mix at deterioration rate, and active packaging such as oxygen scavenger in the package material.

As an example, consider the effects of combining temperature and environmental gas control, i.e., modified atmosphere, for a prepared center-of-the-plate, meat-based, sauced product recipe. It involves rapid temperature reduction (less than 2 hr from heat to chill) to reduce the rates of deterioration according to the Arrhenius equation; clean fill; oxygen reduction to reduce oxidations that so severely alter the product over time; carbon dioxide elevation to suppress the growth of most microorganisms; and hermetically sealed gas-barrier packaging to maintain the gas. That combination of hurdles has the potential to provide safe quality retention for up to three weeks-if temperature is maintained during distribution and if the barrier integrity of the package is not compromised. By incorporating a film-sealed barrier-polypropy-lene tray capable of releasing steam, the product portion might be reheatable within 3 min in a turn-table 900-Watt microwave oven. And the target consumer can eat fine food from the tray.

What proportion of shelf life is provided by the temperature reduction and how much by each of the other hurdles? How much shelf life is offered by the chef ’s thermal input that reduces the microbiological load by a factor of possibly ten? If the reference life as chef-prepared is 4 hr from the chef ’s hands-a not-improbable time-imposition of chilled temperature control might suggest a shelf life of up to ten days-with the chef ’s heating procedure obviating the microbiological issues during this period.

Gas control—more often called modified atmosphere—provides double or more the base reduced-temperature time, i.e., chilling preservation is enhanced by alteration of the gaseous environment. Microbiological issues usually do not arise until well after the biochemical oxidations are initiated.

These rules of thumb cannot yet be applied as quantitative science, but can be used as guidelines to begin the laboratory shelf-life-evaluation protocols. Newer nonthermal technologies offer promise to further extend shelf life; these include ultra high pressure; active packaging; and even low-dose ionizing radiation— electron-beam, gamma, and X-ray—when it finally arrives.

Holistic Hurdles and the Chef’s Gold Standard
We hold that all professional members of the food community are created approximately equal—and that the increasingly visible chef ’s contribution must be transmitted to our favorite people—our target consumers. In these formative phases of our soon-to-be-consummated melding, some might take issue with the establishment of a “gold standard.” (Interestingly, some food scientists and technologists even today actually perceive of packaging as being an unnecessary evil.) And some would argue that never will science and art meet, especially on the playing fields of food preparation and preservation. But please do not convey to our precious consumers that all of us are not working diligently together to deliver the best flavor safely at the lowest price. The gold standard coupled with hurdle technologies represents our latest tool to elate our customers and elevate our status in their consciousness.

Contributing Editor
President and CEO,
Packaging/Brody, Inc., Duluth, Ga.
[email protected]

In This Article

  1. Food Processing & Packaging