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ONLINE EXCLUSIVE: Sprouts Can Be Safe
by Art Davis
In the 1980s and on into the mid- to late 1990s, sprouts of one variety or another appeared on virtually every salad bar and most deli sandwiches. They were widely accepted as a tasty and healthful addition to any diet. Alfalfa sprouts were most common, with clover, radish, and onion sprouts often offered as alternatives for enhanced flavor.
Sprout producers were generally small businesses, often started in basements and garages, growing sprouts in containers including gallon jars, small barrels, and, for the slightly larger operator, children’s wading pools. Seeds for sprouting were purchased from local suppliers like “co-op” stores or, again for the larger grower, one of a few national level sources. The seeds for sprouting were not differentiated from seeds intended for conventional planting and crop production.
One early sprouter was also involved in the family seed business, selling agricultural seed to landscapers, land reclamation operations, and farmers. With access to seed, especially alfalfa seed, from a variety of sources, this sprouter soon noticed that all seed was not created equal in terms of the quantity and quality of edible sprouts produced. Initially, the sprouter used this knowledge to enhance his own sprout growing operation, but he soon realized there might well be a market for superior quality sprouting seed among the growing number of small sprout producers across the country.
This sprouter found a niche as a seed supplier and is now, though no longer an active sprout grower, one of the two major seed suppliers to American sprouters. He has been at the forefront in developing seed handling systems specifically for sprouting seed. His company is developing a seed treatment process that provides sprouting seed with a significantly reduced level of microbial contamination.
At about this same time, a NASA invention, originally designed to grow assorted greens in a weightless environment, was adapted to allow semi-automated growth of commercial quantities of sprouts just about anywhere with space, water supply, and a drain. “Rotary drum” sprouting systems of one sort or another became the standard method for green sprout production.
At the peak of the sprouting business, there were more than a hundred small sprouters scattered across the country. Sprouting appealed to folks with little capital who wanted to run their own business and were, at least to some degree, committed to natural, minimal input food production. Few, if any, of the early sprout producers had significant training in microbiology, chemistry, or any other science relevant to the safe production of food.
The advent, in the early to mid-1990s, of superior systems designed to detect and track foodborne disease resulted in the discovery of many microbial contamination issues in food products not previously seen as high risk. Sprouts were among the most heavily impacted as one foodborne disease outbreak after another was traced back to what had been considered a safe and wholesome form of fresh food. With these findings, FDA and CDC interest in sprouts and sprouting grew.
As investigations continued, it became obvious that sprout seed was the likely source of many if not most of the disease outbreaks traced to sprouts. Many types of seed treatments were investigated by government and university research groups. Although complete eradication of bacteria on seed remained an elusive goal, a method first published by Larry Beauchat, PhD, a research professor at the Center for Food Safety at the University of Georgia, became the standard. Dr. Beauchat’s application of a 20,000 ppm calcium hypochlorite solution to seed prior to sprouting was incorporated as the reference seed treatment in a 1999 FDA guidance document.
Also included in the guidance document was a testing system that takes advantage of two factors in rotary drum production of sprouts, originally proposed by Katherine Swanson, PhD, vice president of food safety at Ecolab. A generally accepted mantra says testing cannot provide food safety due to sampling error and time required for results. In the case of rotary drum sprout production, both of these issues are easily overcome.
Based on work done by Dr. Swanson and Ruth Petran in their lab at The Pillsbury Company and duplicated by others, microbial growth in sprout seed under rotary drum conditions (warm and wet) is very rapid with a peak in growth of pathogenic organisms at about 48 hours. Rotary drums have an internal irrigation system that adds water to the rotating mass of sprouts several times per hour, primarily to keep the sprout mass cool. Excess water flows out of the drum after mixing thoroughly with the sprouts. This excess water provides a complete sample of whatever microbes may be growing in the drum. Sampling the water at 48 hours leaves at least another 48 hours, often a few more, before the sampled sprouts are harvested. With modern microbiological detection systems, 48 hours is more than sufficient time to determine the presence or absence of pathogenic organisms prior to harvest.
This system of testing spent irrigation water from sprouting systems is included in the 1999 guidance document, along with the suggestion that both the 20,000 ppm calcium hypochlorite seed treatment and irrigation water testing are an appropriate standard for the industry.
Unfortunately, the suggestions in the FDA guidance document, while widely adopted by many sprouters, have not been adopted by a significant number of (usually smaller) sprouters. Sprouters who have not adopted or have only partially adopted FDA guidance suggestions have voiced objections to the use of chlorine (especially as it violates organic production standards) and to the cost of testing spent irrigation water, and have even questioned the epidemiological statistics that have repeatedly determined sprouts to be the source of foodborne disease outbreaks.
A number of larger sprouters follow the 1999 FDA guidance, in addition to standard GMPs, and are producing in buildings designed and built as food production facilities. These sprouters produce a significant proportion of the sprout products available and have done so without being associated with foodborne disease outbreaks over the past 10 years. The common factors among sprouters associated with outbreaks are smaller size, buildings not designed and built as food production facilities, limited background and training in scientific food safety, and, perhaps most important, ideological and/or financial objections to one or more aspects of the 1999 FDA guidance.
Sprouts can be grown and marketed with a reasonable level of safety, as demonstrated by the larger sprout producers who have followed the 1999 FDA guidance over the past 10-plus years. It is unfortunate that a few smaller sprouters operating with ideological and resource constraints are able to harm consumers and damage the market.
Art Davis is a food industry veteran and consultant with more than 30 years’ experience. He has served as vice president of food safety for The Vista Institute, vice president of produce for IEH Laboratories and Consultants, and vice president of operations for The Sholl Group II/Green Giant Fresh.