Food or edible material: processes – compositions – and products – Inhibiting chemical or physical change of food by contact... – Animal flesh – citrus fruit – bean or cereal seed material
Reexamination Certificate
1999-05-04
2001-12-04
Pratt, Helen (Department: 1761)
Food or edible material: processes, compositions, and products
Inhibiting chemical or physical change of food by contact...
Animal flesh, citrus fruit, bean or cereal seed material
C426S335000, C426S532000, C426S626000, C426S650000
Reexamination Certificate
active
06326042
ABSTRACT:
BACKGROUND OF THE INVENTION
Trends toward shorter cooking times, consumer demand for safety, and willingness to use litigation are increasing the pressure on the food industry to reduce risks in the food chain. Meats are of particular concern because they are easily contaminated with microorganisms and are an ideal environment for growth of bacteria. Pathogens such as Salmonella, Campylobacter, Listeria, Clostridium,
Escherichia coli
O157:H7, and the like can be present. Salmonella and
Campylobacter jejuni
are the leading causes of bacterial diarrhea. Listeria ingestion results in a high mortality rate.
Escherichia coli
O157:H7 is also particularly severe and the number of incidences are increasing.
In late 1992 and early 1993, a very large outbreak of
E. coli
O157:H7 infections occurred in Washington and several other western states. More than 500 confirmed infections in four states occurred, with 51 cases of emolytic uremic syndrome (HUS), and four deaths. This outbreak, traced to undercooked hamburgers served at multiple outlets of the same fast food chain (Centers for Disease Control and Prevention [1993] Update: Multistate Outbreak of
Escherichia coli
O157:H7 Infections from Hamburgers—Western United States, 1992-1993, Morbidity Mortality Weekly Report, 42:258-263) placed food safety, and
E. coli
O157:H7 in particular, into public, industrial, and regulatory prominence. With increased recognition of
E. coli
O157:H7 infections has come the investigation of increasing numbers of outbreaks, leading to the recognition of many “new” vehicles, including some foods not traditionally associated with enteric infections, such as dry-cured salami and lettuce (Tarr, P. I. et al., [1997], “Verotoxigenic
Escherichia coli
infection: U.S. overview,”
J. Food Protection
60:1466-1471) indicating this organism is particularly hardy. The number of outbreaks of
E. coli
O157:H7 infections reported to the Centers for Disease Control and Prevention (CDC) has increased in recent years. The Food and Drug Administration (FDA) approximates 25,000 cases of foodborne illness can be attributed to
E. coli
O157:H7 infections each year with as many as 100 deaths (FDA, [1997], “Food safety from farm to table: a national food safety initiative,” Report to the President, Washington, D.C.). In 1989, the annual cost of
E. coli
infections was estimated at $223 million (Todd, E. C. D. [1989] “Preliminary estimates of costs of foodborne disease in the United States,
J. Food Protection
52:595-601).
Analysis of foods associated with outbreaks of
E. coli
O157:H7 reveals that the infective dose is low. For example, 0.3 to 0.4
E. coli
O157:H7 cells per g were detected in several intact packages of salami that were associated with a foodborne outbreak (Centers for Disease Control and Prevention [1995], “Surveillance for outbreaks of
Escherichia coli
O157:H7 infections-preliminary summary '94, Surveillance Summary No. SS-5”). This suggests that the infectious dose is quite low, less than a few hundred cells. Additional evidence for a low infectious dose is the capability for person-to-person transmission of
E. coli
O157:H7 infection. The serious nature of the disease combined with its apparent low infectious dose (<100 cells) qualify
E. coli
O157:H7 to be among the most serious of known foodborne pathogens.
Enteric bacterial pathogens must survive the acidity of the stomach before they reach the intestine and cause illness. Inoculation studies revealed that
E. coli
O157:H7 can survive fermentation, drying, and storage of fermented sausage for up to two months with only ca. 2 log
10
decrease (Glass, K. A. et al., [1992] “Fate of
Escherichia coli
O157:H7 as affected by pH or sodium chloride and in fermented, dry sausage,” Applied and
Environmental Microbioloogy,
58:2513-2516). In 1991, an outbreak of serotype O157:H7 that infected 23 persons was traced to the consumption of fresh-pressed apple cider (Besser, R. E. et al., “An outbreak of diarrhea and hemolytic uremic syndrome from
Escherichia coli
O157:H7 in fresh-pressed apple cider,” [1993
] J. Am. Med. Asso.
269:2217-2220). The implicated cider had a pH value of 3.7 to 3.9 and contained no preservatives. The ability of
E. coli
O157:H7 to tolerate acidity was substantiated in 1993 when mayonnaise was implicated in a series of restaurant outbreaks that infected at least 48 people (Weagant, S. D. et al., [1994], “Survival of
Escherichia coli
O157:H7 in mayonnaise and mayonnaise-based sauces at room and refrigerated temperatures,”
J. Food Protection
57:629-631). Hot sprays of acetic, citric, and lactic acids at concentrations up to 1.5% did not have an inhibitory effect on
E. coli
O157:H7 in raw beef (Brackett, R. E. et al., [1994] “Ineffectiveness of hot acid sprays to decontaminate
Escherichia coli
O157:H7 on beef,”
J. Food Protection
57:198-203). The mechanism of acid tolerance of serotype O157:H7 has not been fully explained, but it appears to be due to the presence of proteins that can be induced by pre-exposing the bacteria to acidic conditions.
The primary source of O157:H7 infection is through beef products, most commonly undercooked ground beef (Boyce, T. G. et al. [1995] “Current Concepts:
Escherichia coli
O157:H7 and the hemolytic uremic syndrome,”
The New Eng. J. Med.
333:364-368).
Today's systems to control pathogenic bacteria still result in periodic food safety problems. Only continued analysis and control (Hazard Analysis Critical Control Point [HACCP]) as implemented by the Food and Drug Administration) and a multifaceted approach will allow a reasonable risk. The Food Safety and Inspection Service (FSIS)-approved antimicrobial treatments include hot water, steam and organic acids, such as lactic acid (up to 2.5%).
The use of organic acids, such as lactic acid, for decontamination of carcasses has been extensively studied because they reduce bacterial counts and are safe. The drawbacks of organic acid sprays is that high concentrations of the acids should not be used because of loss of sensory quality. Discoloration and the threshold for tasting the acid begins at about two percent.
Lactic acid has been used as an antimicrobial agent for treating animal carcasses. See U.S. Pat. No. 5,178,890, issued Jan. 12, 1993 to van den Niewelaar et al. for “Method for Improving the Bacteriological Quality of Slaughtered Poultry”; Grau, F. H. (1986), “Microbial Ecology of Meat and Poultry,”
Advances in Meat Research,
2:1-47; and U.S. Pat. No. 5,093,140 issued Mar. 3, 1992 to Watanabe for “Aqueous Bactericide for Animal Treatment.” Application of lactic acid to meats causes a pH drop which results in death and sublethal injury to microorganisms (Anderson, M. E. and Marshall, R. T. [1989], “Interaction of concentration and temperature of acetic acid solution on reduction of various species of microorganisms on beef surface,”
J. Food Protection
52(5):312-315). The pH remains low for a relatively short time because of the natural buffering in meat as discussed above. After spraying of hot calf carcasses with 1.25% (v/v) lactic acid, a surface pH fall of more than three units has been found. However, after 72 hours the pH had returned to its initial value. Repeating a lactic acid treatment of broiler carcasses neither decreased the surface pH further nor enhanced the bacteriostatic and bactericidal effects. See Woolthuis, C. H. J. and Smulders, F. J. M. (1985), “Microbial Decontamination of Calf Carcasses by Lactic Acid Sprays,”
J. Food Protection
48(10)832-837;
At high levels of initial contamination acceptable concentrations of lactic acid may not effect marked microbial lethality as theorized by Baird-Parker (Baird-Parker, A. C. [1980] “Organic Acids,” in
Microbial Ecology of Foods. I Factors affecting life and death ofmicroorganismzs
,” J. H. Silliker et al. (eds.), Academic Press, New York, pp. 126-135). When the initial contamination was low, the lethality eff
Allanson Ann
Iannotti Eugene L.
Jin Zhonglin
Mueller Richard E.
Unklesbay Nan
Greenlee Winner and Sullivan P.C.
Pratt Helen
The Curators of the University of Missouri
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