Volume XXI, Number III, September/October, 1997
Al Wagner
Associate Head/Program Leader Horticulture, TAEX
Understanding and Preventing Virus Transmission via Foods
Salsa Shoppers Prefer New Flavors Over Heat
Heating Characteristics of Glass Containers During pH-based Hot-Fill-Hold Process
Pushing the Right Buttons
Items of Interest
E.Coli 0157:H7 Associated with Alfalfa Sprouts
Alcohol and Heart Disease
1997 Almanac Published
Rules and Regulations
Coming Events 5
Announcements
Processing of Nutraceuticals
A practical short course on ãProcessing of Nutraceuticals,ä including their preparation, extraction, separation, purification, regulation, and packaging will be held February 15-17, 1998, in Houston, Texas. For more information, contact Dr. Sefa Koseoglu or Mr. S. Gregory at Food Protein R&D Center (409) 845-2741.
New Developments in Membrane Technology
A short course on "New Developments in Membrane Technology for Food and Wastewater" will be held March 1-5, 1998, in Houston, Texas. For registration information, contact Dr. Koseoglu or Mr. Gregory at (409) 845-2741.
News
Understanding and Preventing Virus Transmission via Foods
By: Theresa L. Cromeans, Ph.D.
Division of Viral and Rickettsial Diseases, CDC
Unlike bacteria, viruses cannot multiply outside of their specific host. Although inert in the environment, viruses transmitted by food are quite hardy and remain infectious in conditions, such as refrigeration and freezing, designed to maintain food quality. Viruses can also withstand the low pH of the stomach and the harsh detergent conditions of the upper small intestine. These and other issues pertinent to the risk of food-borne viral diseases are explained in the Scientific Status Summary, ãVirus Transmission via Food,ä prepared for Institute of Food Technologists' Expert Panel on Food Safety and Nutrition by Dean Cliver.
Hepatitis A, a reportable disease in all states, and the gastroenteritis viruses (Norwalk and Norwalk-like viruses, collectively Small Round Structured Viruses -- SRSV) cause the majority of food-borne viral disease. The proportion of reported cases of hepatitis A thought to be caused by contaminated food and water is only 2 to 3 percent. Contact with a person with clinically apparent infection is the most frequently reported source of hepatitis A (22 to 26 percent); but in more than 40 percent of reported cases, no source for infection has been identified. Regarding person-to-person transmission, hepatitis A virus (HAV) is shed by infected people for two weeks before the onset of symptoms, and infected individuals excrete virus in concentrations as high as 108 particles per gram of fecal matter. In addition, most infected children less than six years of age usually do not have symptoms, and may shed the virus for longer periods of time than adults.
Gastroenteritis is not a reportable disease; thus, the proportion of illness due to food-borne transmission of viruses other than HAV is not known. Important aspects of viral gastroenteritis include the presence of virus in vomitus and its possible excretion for seven days after the onset of illness. In addition, the immunity induced by SRSV may not be lifelong; genetic variations of the gastroenteritis viruses enable repeated infections with similar symptoms. In contrast, HAV infection confers lifelong immunity.
Detection of viruses in food is difficult. Testing for bacterial indicators does not routinely predict viral contamination. Routine examination of food for viruses is not practical because of the small quantity of viruses in relation to the size and biochemical complexity of food samples. Furthermore, HAV grows poorly in cell culture, and SRSV does not grow in cell culture. Much recent progress has been made, however, in detecting viral nucleic acid by amplifications with the polymerase chain reaction (PCR). For example, PCR detection of only 0.2 infectious particles of virus per gram of oyster meat has been reported (Jaykus et al., 1996). Detection at this level of sensitivity is time-consuming and not feasible for routine use. Rather, PCR is most useful in determining source and transmission patterns of outbreaks.
The points of potential contamination determine the appropriate intervention strategy for preventing disease. Food may be contaminated at the source (i.e., polluted shellfish beds, vegetable growing fields, or during processing). Preventing this type of contamination requires monitoring of water overlying shellfish beds, as well as providing sanitary facilities for food workers and enforcement of sanitary practices. Food may also be contaminated while being prepared for consumption; uncooked foods will remain infectious. The most effective prevention strategy is good hygiene, including thorough hand washing, among food handlers.
Inactivated hepatitis A vaccine, given prior to exposure, is 95 percent effective in preventing hepatitis A. Although vaccination of food handlers, as suggested by Cliver and others, may appear of value, there is little epidemiologic support for such an approach in the United States. Less than 5 percent of reported cases of hepatitis A occur in the context of a food-borne outbreak, and routine vaccination of food handlers is not cost-effective (Meltzer, Shapiro, and Mast, CDC, unpublished data). Routine vaccination of food handlers is not viewed as a public health priority, and it would not be expected to reduce disease incidence other than by immunizing a sizeable segment of the adolescent and young-adult population. In certain community-wide outbreaks of hepatitis A, food handler-associated disease might warrant vaccination. This strategy, however, has not been evaluated. For prevention of hepatitis A, the best immunization strategy will be routine vaccination of children. Preventing food-borne virus infections, however, will continue to require foremost attention to ensuring that foods consumed uncooked are not contaminated during growth, harvest, and production.
This article appeared in the April issue of Food Technology.
Salsa Shoppers Prefer New Flavors Over Heat
Supermarket sales of salsa combined with cheese, roasted garlic, onions, and other flavors increased 58 percent to $70.3 million in 1996, according to the Food Instituteâs Supermarket Analysis Series: Tomato Products. Meanwhile, consumersâ taste for hot salsa cooled off, as sales dropped almost 9 percent to $43.8 million. 'Medium' and 'mild' continue to be the most popular types of salsa for shoppers, ringing up $197.6 million and $192.4 million in sales, respectively.
While sales increased by less than 1 percent in the 'medium' category and by 1.9 percent in the 'mild' category, sales of Frito Layâs Tostitos¨ increased 23.2 percent in 'medium' category and 26.5 percent in the 'mild' category.
Overall supermarket sales of shelf-stable tomatoes and tomato-based products totaled 3.9 billion pounds last year, up just 0.4 percent from 1995. The dollar value of the sales was $3.8 billion, up 3.3 percent from 1995, according to analysis of IRI InfoScan data in the 1997 edition of Supermarket Analysis Series: Tomato Products.
For more information about this publication, including a table of contents, call Ivy Rubin at (201) 791-5570, extension 12, or e-mail irubin@foodinstitute.com, or visit their on-line catalog at http://www.foodinstitute.com.
Heating Characteristics of Glass Containers During pH-Based Hot-Fill-Hold Processes
There has been increasing interest in the food industry to optimize pH-based hot-fill-hold (HFH) processes for juice products. Current guidelines for these processes are primarily based on historical data and are very conservative. There is little published experimental data on actual temperatures needed in containers and caps to achieve commercial sterility. The objective of this study was to determine the heating characteristics of glass containers and caps during HFH processes.
Temperature profile studies were conducted by simulating hot-fill-hold processes for 10-oz. bottles with 35-mm caps and 48-oz. bottles with 48-mm caps. The temperature profiles of the product (water) and the glass wall, cap, and atmosphere in the head-space area were determined at the fill temperatures of 1700 F, 1800 F, 1900 F, and 1950 F. In each test, the bottles were filled, sealed, and held in vertical and horizontal positions for about 4 minutes. Cumulative lethalities were computed using the general method.
There was great variability in the temperature and lethality data for bottles held vertically with the same fill temperatures. The cap and glass wall were the coolest spots of the head-space area. Temperature differentials between the average cap and glass wall temperatures were in the range of 300 F to 5000 F at the 1700 F fill temperature for both bottle sizes. Holding bottles in the vertical position resulted in cap and glass wall temperatures which were much lower than those of bottles held in the horizontal position with the same fill temperatures. The cap was overall hotter than the glass wall in the horizontal-hold position, while the opposite was true for the vertical position. This study provides information on container temperature, temperature variability, and other factors needed for optimizing HFH processes. For more information, contact Joshua Mugerwa at (202) 639-5952, or jmugerw@nfpa-food.org.
Taken from National Food Processors Association Information Letter, July 1997. The authors are employees of the association.
Pushing the Right Buttons
Soliciting business on the Web is not always all it is cracked up to be. Businesses are quick to realize the drawbacks to making money via the Internet: namely, the audience is far smaller than that of other mass media, and they are spread out across vast expanses of the information superhighway. Furthermore, users are utilizing an interactive medium, and are in control of what they wish to view, and when.
Some organizations are hoping to counteract this barrier with a new approach called 'push' technology. Instead of the user pulling ads and information from cyberspace that he finds relevant, push technology does this for him by broadcasting selected material to his screen. The data is presented to an individualâs PC in the form of a screen saver, with headlines and flowing text, that users can easily call up and access.
The concept originated at a couple of California-based software companies. Now, both Microsoft and Netscape, as well as other major companies, are in hot pursuit with their own versions. Current applications of push technology are downloaded from the companyâs Web site. The user chooses which 'channels' he wishes to receive, such as industry information, or general topics like sports or business; the program then travels the Internet, retrieving the relevant data, and delivers it to the userâs screen. The overriding concern with push technology boils down to one basic question: is the nature of the PC that of an active or passive medium?
Items of Interest
E.coli O157:H7 Associated With Alfalfa Sprouts
Outbreaks of E.coli O157:H7 in June and July in Michigan and Virginia were associated with the consumption of alfalfa sprouts that probably became contaminated as seeds, the Center for Disease Control and Prevention reported on August 15 in Morbidity and Mortality Weekly Report. The sprouts from both outbreaks were traced back to a single seed distributor, although environmental samples from the distributor did not uncover the pathogen. People at risk of severe complications from food-borne illness can reduce this risk by not eating raw alfalfa sprouts, CDC said. Research has not identified an effective means of decontaminating alfalfa seeds. ãStudies of alfalfa seed inoculated with low numbers of Salmonella suggest that the number of organisms present on seeds may increase up to 10,000-fold during the sprouting process,ä CDC said. Alfalfa sprouts have been associated with past outbreaks of Salmonella.
CDC. 1997. Outbreaks of Escherichia coli O157:H7 infection associated with eating alfalfa sprouts--Michigan and Virginia, June-July 1997. Available from IFT Science Communications or at <www.cdc.gov/epo/mmwr_wk.html>, #97.148. Taken from Institute of Food Technologists Science Communicators Alert.
1997 Almanac Published
The 1997 Almanac of the Canning, Freezing and Preserving Industries, 80th Edition, updated through June 1997, is now in distribution.
Features new to this 80th Almanac include: two new final FDA rules on Nutrient Content Labeling Claims; USDA Quality Grade Standards for frozen cauliflower, frozen okra, frozen field peas and black-eyed peas; Food Quality Protection Act amendments to the Federal Food, Drug, and Cosmetic Act, and reference to the FDAâs new proposed rule regarding Net Quantity of Contents Compliance.
All FDA and USDA regulations, food laws, agricultural statistics, final packs, and imports/exports have been updated.
At 824 pages, the 1997 Almanac is the largest ever. Every complete food marketing, manufacturing and research library will contain this thoroughly revised and indexed "warehouse of food information.ä
Copies may be ordered by phone, fax, or mail from: Edward E. Judge & Sons, Inc. Publishers, P.O. Box 866, Westminster, MD 21158. Telephone (800) 729-5517, or fax: (410) 848-2034.
Alcohol and Heart Disease
Moderate drinking of all types of alcoholic beverages, not just red wine, may protect against coronary heart disease, California researchers concluded in an eight-year study. The researchers cross-referenced alcohol intake information obtained during the health examinations of more than 128,000 men and women hospitalized due to cardiac problems. Beer and red or white wines offer slightly more protection than liquor, Reuters said on August 21. However, researchers concluded that ãadditional protection by specific beverages is minor.ä (American Journal of Cardiology. 1997:416-20).
Rules and Regulations
Fresh Juice Safety
A 'Notice of Intent' describing the steps the Food and Drug Administration plans to take to promote the safety of fresh fruit and vegetable juices was published in the Federal Register, August 28, 62FR 45593-6. The action stemmed in large part from last yearâs E. coli outbreak from unpasteurized apple juice which sickened 66 people in three Western states and Canada, and resulted in the death of one child. The new measures affect only a small number of producers, because more than 98 percent of all fruit and vegetable juices is already pasteurized.
A three-pronged approach is planned by the FDA; it is summarized below from a memo issued by Olsson, Frank & Weeda, P.C., Washington, DC:
1. Mandatory Hazard Analysis Critical Control Point (HACCP) Program. FDA plans to propose a regulation that will mandate development of plant-specific HACCP programs for some or all juice products. The initiative will be phased in over a period of time, however, to allow companies to develop and implement HACCP plans.
2. Label Warning Statements. As an interim measure, FDA plans to propose a regulation that juice products not produced under an HACCP program or treated to prevent or destroy potentially harmful bacteria, bear a warning statement such as:
ãWarning: This product has not been pasteurized and, therefore, may contain harmful bacteria which can cause serious illness in children, the elderly, and persons with weakened immune systems.ä
FDA is also considering whether a warning statement would not be required if juice is subjected to a treatment that results in a 5-log reduction in E. coli O157:H7 or other pathogens. Currently, however, FDA recognizes pasteurization as the only process validated to meet this standard, but has requested information on other ways to achieve the reduction.
3. Educational Program. FDA intends to coordinate with state and local officials, industry, and consumer groups regarding consumer and education outreach programs.
Source: Food Institute Report - September 1997