Agency Response Letter - Objection; Starter Growth Media; FALP No. 001 (Docket No. 2006FL-0238)
Mali Reddy, D.V.M., Ph.D.
International Media and Cultures, Inc.
1250 South Parker Road
Denver, Colorado 80231
Dear Dr. Reddy:
This is in regard to the petition dated June 1, 2006, that International Media and Cultures, Inc. (IMAC) submitted to the Food and Drug Administration (FDA) in accordance with section 403(w)(6) of the Federal Food, Drug, and Cosmetic Act (21 U.S.C. 343(w)(6)) (the Act). Under section 403(w)(6), any person may petition FDA to exempt a food ingredient described in section 201(qq)(2) of the Act from the allergen labeling requirements of section 403(w). The burden is on the petitioner to provide scientific evidence (including the analytical method used to produce the evidence) that demonstrates that such food ingredient, as derived by the method specified in the petition, does not cause an allergic response that poses a risk to human health. FDA received the submission on June 5, 2006, and designated it as Food Allergen Labeling Petition (FALP) 001.
IMAC is a manufacturer of starter culture media (starter media) that are used to grow starter cultures for the manufacture of cheeses. It appears that FALP 001 is intended to inform FDA of IMAC’s view that the enzyme treated soy solids  used as an ingredient in IMAC’s starter media are exempt from food allergen labeling requirements and thus need not be declared on the label of cheese products produced using starter cultures grown in IMAC starter media. According to FALP 001, the soy solids in the starter media undergo enzymatic and acid hydrolysis during the production of starter media, production of starter cultures, and production and storage of cheese. FALP 001 contends that, as a consequence of this hydrolysis, the soy proteins originally present in the starter media degrade to such an extent that they are not capable of causing an allergic response that poses a risk to human health when consumed by sensitive individuals.
FALP 001 presents historical information on the development of the IMAC starter media, a description of how the starter media are manufactured, information on the use of these starter media to prepare starter cultures, data on protein measurements carried out with various media, cultures, and cheeses, data on immunoassays carried out with extracts of various cheeses, and the results of a food challenge study carried out using cheese made with starter cultures grown in IMAC starter media. The petition also contains information on the amount of cheese manufactured to date using starter cultures grown in IMAC starter media and estimates of the number of consumers exposed to this cheese.
FDA is denying FALP 001. As discussed in detail below, FALP 001 does not provide scientific evidence (including the analytical method used to produce the evidence) that demonstrates that either the IMAC starter media or cheese made using starter cultures grown in IMAC starter media with enzyme treated soy solids, as derived by the method specified in the petition, do not cause an allergic response that poses a risk to human health, as required by section 403(w)(6).
FALP 001 is neither clear nor consistent as to the specific ingredient that is the subject of the petition. The cover letter states that the petition is for "IMAC media with enzyme treated soy solids as one of the ingredients." This wording is also used on page 32 of the petition. And on page 16, the petition states that the subject is "soy solids in IMAC media and method of preparation of starter, cheese, etc." However, the cover page of the actual petition states that it is for "…finished cheese, when IMAC…media with enzyme treated soy as one of the ingredients used to prepare cheese culture to make cheese [sic]," and on page 27 the petition states that the requested exemption is for "cheese made with IMAC starter media." To the extent that the requested exemption is for cheese, FDA notes that IMAC starter media are used by a number of companies in a variety of different ways to manufacture finished cheese- for consumer use.
The information FALP 001 is not sufficient to establish the nature or level of soy proteins present either in the IMAC starter media or in finished cheese produced using starter cultures grown in IMAC starter media, for multiple reasons.
First, the petition does not clearly describe the composition of the various media that are the subject of the petition. The petition states that IMAC makes both enzyme-containing and non-enzyme-containing versions of three media. The details of how each is manufactured and of the composition of each are not provided. For example, the petition states that "the amount of carbohydrates varies from 15% to 45% depends on the concentration of the culture required [sic]." The petition also states that "the protein concentration has to be varied [sic]" in relation to the level of phosphates and that "this is proprietary information." As noted, the petition asserts that soy proteins in the IMAC starter media are hydrolyzed at various stages of the media production and cheese-making process. Thus, detailed information on the composition of the various media is necessary to determine the effect of hydrolysis and the cheese making process on the level of consumer exposure to soy proteins and peptides derived from soy proteins. But the petition does not include such information.
Second, although FALP 001 claims that the use of the IMAC starter media in cheese-making results in hydrolysis of the soy solids, thus rendering the soy proteins non-allergenic, the specific conditions under which these media are used, and thus the degree of hydrolysis of the soy proteins, are determined by the individual cheese manufacturer. These conditions may vary greatly. For example, as stated in the petition, the batch size may vary from 500 to 2000 gallons and the time taken to heat the reconstituted medium may vary from 1.25 to 1.75 hours. The specific starter culture used also varies depending on the type of cheese and the source of the starter. The petition acknowledges that "variations are practiced in the plants according to their requirements." Due to this variation, it is not possible to determine, using the information in the petition, the final amount or condition of the soy solids in the finished cheese as actually manufactured. Given this shortcoming, the petition does not demonstrate that cheese made using starter cultures grown in IMAC starter media does not cause an allergic reaction that poses a risk to human health.
Third, the information in FALP 001 on the measurement of protein levels in media before, and in culture supernatants after, the growth of starter cultures is inconclusive. These studies use a dye binding assay to determine the amount of protein in the starter media as well as in the culture supernatants. However, the petition does not provide information describing the details of the procedures used to obtain these measurements, the methods of sample preparation, the number and sizes of the samples tested, the actual measurements obtained, the specifics of the calculations used to determine percent reduction in total protein, or whether the assays have been validated for measuring proteins in microbial cultures or cheese extracts. Without such information, it is not possible to confirm the calculations done to arrive at the values for the extent of proteolysis as listed in Tables 1, 2 and 3 in Section 16c (pages 88-90) or the level of consumer exposure to soy proteins and peptides in the finished cheese.
Also, FALP 001 does not provide support for the statement that "protein in the supernatant is the soluble protein, which is simpler short chain peptides such as DI and TRI peptides [sic]." In fact, this statement is inconsistent with the chemistry behind the dye binding assay and with other statements in the petition. For example, the petition states (page 86) that the "reagent dye binds with the larger protein complexes (larger than 3 amino acid units)." Thus, the size of the proteins or peptides present in the supernatant that were measurable by the dye binding assay should be at least greater than three amino acid units, and may be substantially larger. The petition does not indicate whether the possible presence of bacteria or bacterial proteins in the culture supernatant was considered in evaluating the results of this assay. The petition also does not provide any information that can be used to determine the size distribution of the soy proteins and peptides present in these samples. Without this size information, it is not possible to evaluate the potential for the supernatant to contain proteins or peptides that are capable of causing an allergic reaction.
The information in FALP 001 addressing assays of finished cheese is not complete. In particular, the petition presents information from the use of a modified ImmunoCap® enzyme immunoassay to detect the presence of soy allergens in cheese made with starter cultures grown in IMAC starter media. However, for several reasons, the petition does not provide sufficient information to evaluate this modified assay.
First, no information is presented as to whether this modified enzyme immunoassay was validated for measuring soy allergens in cheese.
Second, the immunosorbent matrix used is not described nor are any details given describing the process for attaching the sample to this matrix. FALP 001 also fails to provide details regarding the experimental design, such as the amount of liquefied cheese samples immobilized onto the immunosorbent matrix, the amount of human serum used, the amount of washing solution used to elute the unbound IgE from the immunosorbent matrix, whether the washing solution affects the detection of IgE by the ImmunoCap system, and the number of samples or replicates tested. More importantly, the petition lacks information regarding the characteristics of the sera used, including validation that these sera are actually reactive to soy allergens.
Third, the experimental details that are presented in FALP 001 show that the proper experimental controls were not used. Specifically, as stated in the petition, starter medium containing soy protein was used as the positive control in these experiments rather than cheese extracts containing known amounts of soy protein. Therefore, it is not possible to evaluate the accuracy or precision of the assay.
Although FALP 001 contains some exposure information, the information presented is not sufficient to enable FDA to evaluate or confirm its accuracy. For example, the petition presents a calculation of expected consumer exposure to soy protein in cheese based on a chart that attempts to correlate activity units measured in the ImmunoCap assay to actual protein concentrations (Table 1, page 114). However, the conversion factors presented in this chart were not obtained directly by using uniform cheese samples spiked with known amounts of soy protein. Instead, samples of two different materials (starter medium and cheese) were tested in the ImmunoCap assay. Expected soy protein levels in the tested cheese samples were calculated using unverified assumptions about the amount of protein hydrolysis that occurred during cheese-making. Further, the petition does not describe how the conversion factors for these three "set points" were used to calculate the rest of the values that appear in Table 1. Therefore, FDA could not evaluate or confirm the accuracy of the exposure calculations based on the values in Table 1.
Fourth, FALP 001 presents information on a single oral challenge study but fails to establish that this study shows that either the IMAC starter media or cheese produced using the IMAC starter media do not cause an allergic response that poses a risk to human health. The oral challenge study was carried out by feeding two complex foods containing different cheese products. The cheese products included one made using a starter culture grown in a medium containing soy protein and enzyme, one made using a starter culture grown in a medium containing soy protein without enzyme, and one made using a starter culture grown in a medium that did not contain soy protein. However, the petition does not provide the actual levels of exposure to soy protein that occurred during the challenge study. Given the difficulties with the protein measurements and calculations, it is not possible to determine the level of exposure to soy protein obtained during the challenge study. Without information on protein exposure levels, the study results have very limited significance in terms of comparing levels of soy in IMAC starter media to levels of soy shown to cause allergic responses in sensitive individuals.
Also, FALP 001 does not provide details of the protocol used for the food challenge study. However, as described, the design and execution of the challenge study reveal several problems with, and limitations to, the study. Although the petition characterizes this challenge as "double blind placebo controlled," the fact that the challenge was monitored by one of the test subjects indicates that the conditions of the study did not meet the accepted criteria for clinical Double Blind Placebo Controlled Food Challenge (DBPCFC) studies. At this time, only appropriately executed clinical oral food challenge tests such as DBPCFC can be used to establish whether an individual is allergic to a food, such as IMAC starter media or cheese produced using such media.
In addition, individuals in the challenge study may not have been appropriate subjects because they were not established to be soy allergic. Indeed, of 11 subjects tested, the petition states that only three subjects "are allergic to soy products (prior clinical history and also confirmed by skin prick test)" (pp. 119) and "cannot stand soy and do not feel well after eating and proven allergic to soy using skin prick test [sic]" (footnote to table on page 123). Thus, only three subjects might have been expected to react to soy protein. Importantly, none of these three subjects reacted to the positive control (which contained soy), which raises questions about their sensitivity to soy. Also, FALP 001 presents no evidence (such as a description of the type and severity of symptoms related to soy exposure) to establish the level of sensitivity of each of these individuals or to show that the three would respond to ingested soy. Instead, all three subjects were designated as soy allergic based on the results of a "skin prick test." However, the protocol for the skin prick test (including the controls tested, wheal size and criteria, other allergens assessed) and data on the results are not provided in FALP 001. Further, it is recognized that a positive skin prick test does not reliably indicate whether an individual has a food allergy. Accordingly, without a clinically relevant soy allergic population for study, the apparently negative results of this study do not demonstrate that cheese prepared using starter cultures grown in IMAC’s enzyme-containing media does not cause an allergic response that poses a risk to human health.
Fifth, FALP 001 asserts that the lack of known complaints regarding allergic reactions by sensitive individuals despite the production of significant amounts of cheese by several manufacturers over the last five years is evidence that any residual soy protein that may be present in these cheese products is no longer capable of causing allergic responses. However, the mere absence of such consumer complaints does not support this conclusion; the absence of evidence is not evidence of absence. Importantly, these cheese products were not labeled as containing soy, so it is unlikely that soy sensitive consumers or their physicians could have identified soy in these cheese products as the source of any reaction. Further, the petition does not describe how the various cheese producers receive, handle, track, record, or investigate consumer complaints. This precludes an evaluation of whether the absence of reported complaints supports a conclusion that no allergic reactions, and no complaints about allergic reactions, occurred. In addition, it is not clear what proportion of the cheese produced by each manufacturer was made using starter cultures prepared using enzyme treated and non-treated media. For all these reasons, the absence of consumer complaints does not support a conclusion that the finished cheese does not cause an allergic response that poses a risk to human health.
Finally, published clinical evidence generally shows that individuals with a food allergy may experience allergic responses following exposure to minute levels of the causative allergen. FALP 001, however, does not provide any information relating the levels of soy exposure from consumption of cheese made using starter cultures grown in IMAC starter media to the levels of soy protein that cause allergic responses in sensitive individuals that are presented in the scientific literature.
FALP 001 informs FDA of IMAC’s view that the subject of the petition does not cause an allergic response that poses a risk to human health. Although it is unclear whether the subject of FALP 001 is IMAC starter media or cheese produced using IMAC starter media, the petition fails to provide scientific evidence (including the analytical method used) that demonstrates that either the starter media or cheese produced using such media, as derived by the method specified in the petition, do not cause an allergic response that poses a risk to human health. Thus, this petition fails to meet the requirements of section 403(w)(6). FDA therefore denies FALP 001.
Michael M. Landa
Deputy Commissioner for Policy
Deputy Director for Regulatory Affairs
Center for Food Safety and Applied Nutrition
Bock SA, Sampson HA, Atkins FM et al. Double-blind, placebo-controlled food challenge (DBPCFC) as an office procedure: a manual. J Allergy Clin Immunol 1988; 82 (6):986-97.
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Bindslev-Jensen C et al. A consensus protocol for the determination of the threshold doses for allergenic foods: how much is too much? Clin Exp Allergy 2004; 34 (5):689-95.
 The term "enzyme treated soy solids" is here used only for the purpose of responding to this petition and should not be considered an endorsement of a particular common or usual name.