Beam me up Scotty: Health Canada approves radiation to treat fresh and frozen raw ground beef

Rob Mancini writes:

Food irradiation is the treatment of food with a type of radiation energy known as ionizing radiation used to kill microorganisms. In Canada, irradiation has been used on products such as potatoes, onions, wheat and spices.  Health Canada has now authorized the use of ionizing radiation to treat fresh and frozen raw ground beef and permit the sale of these products in Canada.

A number of concerns regarding the use of irradiation were brought forth to the attention of Health Canada including the formation of hydrogen peroxide and alkylcyclobutanones. Health Canada states that hydrogen peroxide is relatively unstable and any residues that may remain on the meat after irradiation are expected to break down to water and oxygen during post-irradiation storage. Alkylcyclobutanones are products referred to as “Unique Radiolytic Products” (URPs) that are derived from fat when irradiated and therefore their presence is directly related to the fat content of the food. These URPs are found in extremely small quantities in irradiated foods, in the order of parts per billion. The overall weight of evidence indicates that the very low levels of these compounds found in irradiated beef do not pose a risk to human health.

I currently live in Winnipeg, Manitoba (Canada) and have been asked a number of times what I’m doing here, cause of the ridiculous cold and short summers. Family is everything to me and they all live in Winnipeg. My parents have kindly suggested that if I take away their grandkids, nothing good will come from that scenario. Winnipeg is also home to food microbiologist guru Dr. Rick Holley whom I have had the pleasure of working with in the past on the CFIA modernization project ranking biological hazards with food commodities. Here is Dr. Holley speaking on food irradiation:

Australia OK’s lychee irradiation centre

I love the produce in sub-tropical Brisbane, but am not a fan of the lychee or the paypaya.

lychees.vietnam.jun.16 The Plant Protection Department under Việt Nam’s Ministry of Agriculture and Rural Development received official recognition from the Australian department yesterday.

The lychees will go through irradiation treatment in Hà Nội instead of being shipped to the south, which helps reduce transport cost and time.

The outcome was attributed to the close co-operation between the Vietnamese Plant Protection Department, Australian competent agencies, and the Australian Embassy in Việt Nam, as well as the active engagement of the Hà Nội Irradiation Centre and businesses.

Any tool to reduce the incidence of foodborne illness or plant disease should be explored.

After decades of consultation, Health Canada to propose allowing irradiated ground beef to be sold

CTV News reports Health Canada will propose regulatory changes to Food and Drug Regulations next month that would allow the sale of irradiated ground beef in Canada.

consult_3A webpage on the department’s website states the proposed amendments would add fresh and frozen raw ground beef to a list of foods that are already permitted to undergo radiation treatment.

It says the purpose would be to would allow, but not require, the beef industry to use irradiation to “improve the safety of their products.”

Health Canada spokeswoman Maryse Durette says the proposed regulations for ground beef will be announced in June in the Canada Gazette and that a public consultation period will follow.

Industry groups in Canada have sought irradiation for over a decade as a way to prevent the spread of E. coli and other dangerous bacteria, but negative public reaction to it has slowed progress.

Health Canada earlier proposed to permit the sale of irradiated ground beef in 2002, but according to the web page it was never finalized “due to mostly negative stakeholder reaction.”

“I think public perception has changed,” says Mark Klassen, director of technical services with the Canadian Cattlemen’s Association, based in Alberta.

The cattlemen’s association first launched an application to use irradiation for ground beef in 1998. Its updated application in 2013 to irradiate all kinds of beef followed a tainted beef recall at what was then the XL Foods plant in southern Alberta.

Bruce Cran of the Consumers Association of Canada, which has been lobbying for irradiation, is pleased with Health Canada’s decision to move forward on ground beef. But he says chicken and salad vegetables should be irradiated, too.

“The science has been in on this one for decades that it does no harm,” says Cran, who adds the risk of foodborne illnesses is high without it.

“They’re going to have a catastrophe if they don’t do something, in my opinion.”

Has that mango been irradiated or you just happy to see me

A trans-Tasman review into the necessity of labelling food treated with ionizing radiation has drawn a mixed response from industry groups, consumers and activists.

Radura.mangoWhile most industry groups and corporations that produced submissions to Food Standards Australia New Zealand were supportive of removing the labelling, all but one of the private citizen submissions were against the idea.

The body will not propose a removal of the current labelling requirements at this stage, but asked respondents whether they thought the countries’ approach to signaling irradiated food was effective or necessary at present.

Irradiation, which is used as both a pest control method and way of extending food’s shelf life, is a rare practice in the two countries, used mainly as a final quarantine measure to prevent the spread of fruit flies.

Some mangoes are treated using irradiation.

Five FSANZ studies over the last 15 years and numerous World Health Organisation reports have found the irradiation process is safe, but food manufacturers are required to add a label informing consumers food has been processed in this way.

The wording of the labelling is not proscribed, though manufacturers can add an optional Radura symbol, the internationally recognised identifier of irradiated food.

Risk reduction: Irradiation of strawberries

Strawberries are vulnerable to harboring microbial pathogens because they are generally not washed due to their perishable nature. The focus of this study was to quantify the reduction in infection risks associated with non-O157 Shiga toxin producing E. coli serotypes contaminated strawberries if the strawberries are exposed to low doses ∼1 kGy (kiloGray) of electron beam (eBeam) irradiation.

strawberry.irradiationA cocktail of six serotypes of non O157 E. coli namely, O26:H11, O45:H2, O103:H2, O111:NM, O121:H19, and O145 was employed. Strawberry puree rather than whole strawberries were used in this study to ensure dose uniformity that is critical for accurate interpretation of microbial reduction.

The results show that when these serotypes are exposed to ≤1 kGy eBeam dose, there is approximately 4-log reduction in their numbers when they are present within a strawberry matrix (puree). Quantitative microbial risk assessments suggest that if a typical strawberry serving (150 g) was heavily contaminated (∼105 CFU/serving size), 2 out of 10 susceptible individuals (20%) would get sick (without eBeam treatment). However, if these contaminated strawberries had been treated with 1 kGy of eBeam dose, the infection risks would have be significantly reduced to approximately 4 out of every 100,000 individuals (0.004%). Similarly, even at low levels of contamination (∼102 CFU/serving), the infection risks would be reduced from 6 out of 10,000 susceptible individuals to approximately 4 out of 100 million susceptible individuals.

Quantifying the reduction in potential infection risks from non-O157 Shiga toxin producing E. coli in strawberries by low dose electron beam processing

Food Control; Available online 7 May 2016; doi:10.1016/j.foodcont.2016.04.057

Shima Shayanfara, Kristina Menab, Suresh D. Pillaia

http://www.sciencedirect.com/science/article/pii/S0956713516302444

Irradiation of almonds to control Salmonella

Two outbreaks of salmonellosis were linked to the consumption of raw almonds from California in 2001 and 2004.

almonds-cssrAs a result, federal regulations were developed, which mandate that all almonds grown in California must be treated with a process that results in a 4-log reduction of Salmonella. Because most of the technologies approved to treat almonds rely on the application of heat to control Salmonella, an evaluation of alternative technologies for inactivating heat-resistant Salmonella Enteritidis PT30 and Salmonella Senftenberg 775W was needed.

In this study, almonds were inoculated with Salmonella Enteritidis PT30 and Salmonella Senftenberg 775W and then treated with an electron beam (e-beam) or by blanching or oil roasting. The irradiation D 10-values for Salmonella Enteritidis PT30 and Salmonella Senftenberg 775W treated with e-beam were 0.90 and 0.72 kGy, respectively. For heat treatments, thermal D 10-values for Salmonella Enteritidis PT30 and Salmonella Senftenberg 775W strains were 15.6 and 12.4 s, respectively, when subjected to blanching at 88°C and 13.2 and 10.9 s, respectively, when roasted in oil at 127 ± 2°C.

No significant differences in irradiation and thermal treatment results were observed between Salmonella Enteritidis PT30 and Salmonella Senftenberg 775W (P > 0.05), indicating that e-beam irradiation may be a feasible technology for reducing Salmonella in almonds. However, the sensory changes resulting from irradiating at the doses used in this study must be evaluated before e-beam irradiation can be used as a nonthermal alternative for decontamination of almonds.

Efficacy of Traditional Almond Decontamination Treatments and Electron Beam Irradiation against Heat-Resistant Salmonella Strains

Journal of Food Protection, Number 3, March 2016, Pages 369-375, DOI: http://dx.doi.org/10.4315/0362-028X.JFP-15-059

P. Cuervo, L. M. Lucia, and A. Castillo

http://www.ingentaconnect.com/content/iafp/jfp/2016/00000079/00000003/art00003

 

Rich Holley says: Food irradiation adds cost but makes sense

Canada was an early adopter of food irradiation, but its status in Canada has remained unchanged for almost 50 years. This article explores reasons for maintenance of the status quo and offers a glimpse of how irradiation can be strategically used to improve the safety of food and the health of Canadians.

Irradiation-beef-Cattlemens-Association-Canada-ionizing-radiation-Ecoli-bacteria-pathogens-EDIWeeklyIf government food safety initiatives and oversight are risk- and science-based in Canada, it is difficult to understand how the current impasse in appraising the application for extended use of food irradiation has occurred. On July 16, 2013, Health Canada granted “expedited status” for the evaluation of a petition from the Canadian Cattleman’s Association (CCA) to use low dose ionizing irradiation to eliminate E. coli O157:H7 from beef.

There has been no meaningful progress to date, and no apparent political will to change that. While the Consumer’s Association of Canada supports adoption of the proposal and is impatient with the lack of progress, Health Canada is reluctant to move forward because of a history of activist opposition to the extended use of food irradiation to other foods1 beyond its permitted use at 0.75 kilogray (kGy) for onions and potatoes, 1.5 kGy for grain and flour, and 10 kGy for spices and dried seasonings. During debates in 1986 and again in 2002 when an initiative for expanded use of food irradiation became a legislative proposal in Canada Gazette Part I, focused opposition led by activists halted its adoption.1 While the CCA petition seems to have been temporarily swept under the rug and although it is hard to determine its status because of regulatory opacity, it appears that there will be little regulatory action until food irradiation is proven harmless to activists. It is uncertain how activists might differ physiologically from the normal consumer; however, it is clear that most are poorly qualified to design, conduct or evaluate scientific work examining the effects of this process on food (Note that issues associated with psychology and psychiatry are beyond the scope of this article).

The scientific basis for the toxicological safety and nutritional adequacy of food irradiated at doses of ≤ 10 kGy has been firmly established as a result of the most extensive body of international research ever accumulated for any food process.2 Doses sufficient for sterilization of food with unaltered sensory characteristics (≤ 60 kGy) were similarly considered acceptable3 and have been used to prepare food for NASA (and Canadian) astronauts for > 40 years. Both Health Canada4 and the CFIA5 have taken positions in support of the use of irradiation to improve the safety of food, but do not permit its use for that purpose in Canada. The safety of irradiated foods has been endorsed by the United States (U.S.) Centers for Disease Control (CDC), the U.S. Department of Agriculture, the U.S. Food and Drug Administration, and is approved for some food use in over 55 countries. Further, the CDC states that “food irradiation is a logical next step to reducing the burden of foodborne disease in the United States”. 6

The greatest potential value from the use of ionizing irradiation to enhance food safety is by treatment of uncooked foods of animal origin, particularly poultry, where “good food” is naturally, unavoidably and consistently contaminated with Campylobacter, Salmonella and toxigenic E. coli (beef), in spite of the best application of good hygienic practices and sanitation in abattoirs and packing plants. With the proliferation of “zero tolerance” rules in North America for pathogens in uncooked foods, the escalating waste and unnecessary cost of recalled animal and plant-based foods because they are not pathogen-free, the use of irradiation becomes an attractive solution. It is ironic that delayed adoption in Canada of expanded animal and plant- based food irradiation and adoption of “zero tolerance” rules have both been driven by “consumer” pressure, which has been fostered by perceived risk to the regulators themselves from the consequences of making either a science-based or politically expedient decision in response to the petition.

The next most strategic target for application of irradiation to improve the safety of food is animal feed. It is folly to ignore the contribution recycling of zoonotic pathogens by feed at both traditional small and large production facilities makes to contamination of human food. It must be remembered that it is within the gastrointestinal tract of healthy domestic animals where pathogens that most frequently cause foodborne illness are resident, multiply and are shed in large numbers from asymptomatic hosts. Irradiation of animal feed would be proactive and complementary to its treatment of food by preventing animal colonization by pathogens, reducing exposure of carcasses to pathogens at slaughter and reducing pathogen contamination of produce by inadequately composted, contaminated manure. Composting can effectively eliminate pathogens from manure but attaining lethal temperatures during the process is unpredictable and almost impossible in most places in Canada during winter. Dependable disinfection of produce cannot currently be achieved by any single treatment (even irradiation) and therefore prevention of contamination is the best, but seldom achieved, option for its safety when used uncooked as human food.

Food irradiation is not a panacea to eliminate foodborne illness but it can reduce its incidence by a substantial proportion and some estimates suggest by 25% if used for poultry, which is the single commodity responsible for most cases of foodborne illness in Canada7 and deaths from foodborne illness in the U.S.8 There are physico-chemical and sensory limits determining which foods can be successfully irradiated to improve safety. At doses effective for controlling bacterial pathogens many dairy products develop “off” flavours and odours caused by lipid oxidation, the whites of treated shell eggs become opaque and less viscous, shellfish (oysters, clams and mussels) die, yielding no advantage, and embryos in treated seeds become non-viable. Except for viruses which are resistant and prions, where the lethal target nuclear material is absent, pathogens can be controlled in most foods at doses ≤ 5 kGy, but if food is frozen or dried higher doses are required. In the U.S., spices and dried herbal seasonings may be irradiated at ≤ 30 kGy for sterilization.6 Although contamination of grains and peanuts by mycotoxigenic fungi can be controlled by irradiation treatment at 5-6 kGy, doses of ≥ 10 kGy are needed to substantially reduce mycotoxin levels in grains.9 Seeds for sprouting may be treated up to 8 kGy6, but in order to maintain the minimum commercial seed germination rate of 95%, lower doses are more practical. In fact, Sikin et al.10 suggested that of all alternatives, including 20,000 ppm chlorine, to ensure the microbial safety of sprouted seeds (a recalcitrant cause of foodborne illness outbreaks), a 50 to 60oC treatment of seeds to be germinated followed by ≤ 2.5 kGy irradiation treatment of the sprouts (mung, radish, broccoli, alfalfa and soy) was the most effective and preserved functional and sensory properties. However, given the small size of individual sprout production operations and their wide geographic distribution, it is unlikely this industry could afford access to irradiation facilities. Fresh produce is increasingly becoming a major contributor to foodborne illness outbreaks, and unlike in Canada where poultry is the leading cause of foodborne illness, leafy green vegetables are the food commodity responsible for causing most illness in the U.S.8 Commercial treatments currently available for disinfecting produce are only marginally effective and irradiation is a viable alternative. Because fresh produce quality is reduced at treatments > 1 kGy, a 220 ppm chlorine wash plus irradiation at 1 kGy11 or a 1 kGy treatment in high oxygen atmospheres12 were the most effective means to assure elimination of both surface and internal pathogen contamination of produce.

Although it is not strictly a food safety application, phytosanitary use of irradiation to control invasive, quarantine insect pests on imported fruits and vegetables has, since 1995, been used on a continuous basis in the U.S. and internationally for mangoes, papaya and a variety of similar products. In Canada, irradiation for insect disinfestation is only permitted for wheat flours and grain at ≤ 1.5 kGy, but for fruits and vegetables lower levels of 0.15 to 0.4 kGy are used commercially with success.13 Because irradiation replaces the use of hot water immersion, heated air and methyl bromide fumigation, which are partly effective or undesirably toxic, the recent growth in phytosanitary use of irradiation can be expected to continue.

A technical problem associated with the more popular use of e-beam irradiation in the U.S. to avoid radioactive waste disposal problems and bad press accompanying use of radioactive isotopes (γ-ray sources) is its low penetrability. Even with double-sided or dual-pass exposures, the thickness of the e-beam target is limited to ≤ 10 cm and this makes it impossible to uniformly treat pallet-sized stacks of packaged food. Although there are also technical and cost issues that need to be overcome, machine generated x-rays are likely to become popular internationally for food irradiation because they have high penetrability, produce no hazardous waste, and the beam generated travels in more controllable parallel lines, rather than dispersed as with γ-rays.13

The claim by activists (Public Citizen) echoed by others (Sierra Club, Food and Water Watch, and the European Civil Society) that irradiation is a “cheap fix” for industry is not borne out by reality. With uncooked foods of animal and plant origin there is no suitable fix available other than irradiation to address “zero tolerance”. In terms of phytosanitary irradiation where alternatives are available for some types of produce to control quarantine insects, they are less expensive than irradiation. Costs of irradiation depend on the dose (type of source) required, proximity to an irradiation facility and throughput. They can range from $0.03 to $1.97/kg ($ U.S.) but can be moderated by efficiencies of scale.13

The formation of compounds (2-alkylcyclobutanones) believed to be uniquely radiolytic in origin and toxic was an objection raised by activists to food irradiation that received attention in earlier discussion. It now appears that they also occur in non-irradiated food14 and may not be acceptable indicators to detect irradiated food, but more importantly this observation minimizes the argument that irradiation does strange things to food. As with any new idea and theory, time is on the side of robust science and eventually will be vindicated.

Objections to the irradiation of food invariably include a call for further whole food (WF) toxicity studies in animals to establish the safety of the process. To date over 30 lifetime WF studies have been conducted involving thousands of animals yielding no measureable effect on safety, yet results were often ambiguous because the studies did not have the sensitivity to identify specific effects of the irradiation treatment. At dietary levels of irradiated components sufficient to test for irradiation effects (chemical changes are so small), an unbalanced diet must be fed, which confounds the outcome.15 With the sophistication and sensitivity of the analytical chemistry technology used today to test for radiolytic products as well as changes in nutrients, unambiguous results are possible and confirm both the nutritional adequacy and toxicological safety of irradiated food, and that further WF toxicity testing is unnecessary.

Summary

While the experimental evidence is very clear that irradiation of food does not produce compositional changes that are of toxicological significance to humans, the controversy continues, fuelled by activists with agenda filled with suspicion of the food industry and regulatory agencies, while “good food” causes 11,000 Canadians to become ill each day16, 2013), and kill an unrecorded number as a result of bacterial pathogens controllable by irradiation. Although I am reluctant to go as far as Farkas and Mohácsi-Farkas2 who suggested that those who provide misinformation about food irradiation are guilty of a form of “terrorism” because they contribute to delayed adoption of a technology that could prevent significant morbidity and mortality, I am disappointed that the evidence to date in Canada shows that the responsible regulatory authority appears reluctant to use available science as the basis for rule making.

References

[1] Gauthier, E. (2010). Social representations of risk in the food irradiation debate in Canada, 1986-2002. Sci. Communication, 32: 295. Available at: http://scx.sagepub.com/content/32/3/295 Accessed Sept. 19, 2014.

[2] Farkas, J. & Mohácsi-Farkas, C. (2011). Trends Food Sci. Technol. 22:121.

[3] WHO (1999). Joint FAO/IAEA/WHO Study Group. High-dose irradiation: wholesomeness of food irradiated with doses above 10 kGy. World Health Organization Technical Report Series 890, Geneva: Available at:

http://apps.who.int/iris/handle/10665/42203#sthash.xI0bA6J5.dpuf Accessed Sept. 23, 2014.

[4] Health Canada (2013). Food irradiation: proposed regulatory changes-archived. Available at: http://www.hc-sc.gc.ca/fn-an/securit/irridation/rlo_pres-eng.php Accessed Sept 23, 2014.

[5] CFIA (2014). Canadian Food Inspection Agency. Food irradiation. Available at: http://www.inspection.gc.ca/food/information-for-consumers/fact-sheets/irradiation/eng/ Accessed Sept 23, 2014.

[6] CDC (2014). Centers for Disease Control, USA. Irradiation of food. Available at: http://www.cdc.gov/nczved/divisions/dfbmd/diseases/irradiation_food/ Accessed Sept 23, 2014.

[7] Ravel, A. et al. (2009). J. Food Protect. 72:1963.

[8] Painter, J.A. et al. (2013). Emerg. Infect. Dis. 19:407.

[9] Calado, T. et al. (2014). Comp. Rev. Food Sci. Food Safety, 13:1049.

[10] Sikin, A. M. et al. (2013). J. Food Protect. 76:2099.

[11] Puerta-Gomez, A.F. et al. (2013). Food Control, 31:410.

[12] Olaimat, A.N. & Holley, R.A. (2012). Food Microbiol. 32: 1-19.

[13] Hallman, G.J. (2011). Comp. Rev. Food Sci. Food Safety, 10:143.

[14] Crews, C. et al. (2012). J. Food Comp. Anal. 26:1.

[15] Bartholomaeus, A. et al. (2013). Crit. Rev. Toxicol. 43:1.

[16] Thomas, M.K. et al. (2013). Food. Path. Dis. 10:639.

Department of Food Science,

University of Manitoba, Winnipeg, Manitoba, R3T 2N2

(*Corresponding author email: rick_holley@umanitoba.ca)

Unlabeled irradiated Australian tomatoes now on NZ shelves

New Zealanders are being urged to once again ask their retailer if their tomatoes have been treated with radiation, as, according to this story, large volumes of unlabelled irradiated Australian tomatoes hit local shelves.

tomato.irradiationThe story says currently there are tonnes of irradiated Australian tomatoes being imported into New Zealand vegetable markets and food retail outlets nationwide, according to Tomatoes New Zealand.

Food retailers and the hospitality sector are legally required to label or indicate where imported irradiated Australian tomatoes are sold or served. However many are unaware that they have a responsibility to their customers to label the produce as irradiated.

Alasdair MacLeod, Chair of Tomatoes New Zealand, said; “We are asking all food and hospitality retailers, including catering companies, to clearly label their irradiated produce at point of sale and on their menus to avoid any public confusion.”

“We are also urging people to register their complaints with the Ministry for Primary Industries via their hotline number and/or email should they believe irradiated Australian tomatoes are being sold without any labeling or signage provided.”

Tomatoes New Zealand is calling on those importing, selling or serving tomatoes to comply with the New Zealand Food Standards Code, which states all food that has been irradiated, or food that contains irradiated ingredients or components, be labeled or have a label displayed on or close to it stating that it has been treated with ionizing radiation.

Unlike Australia, New Zealand does not have mandatory country of origin labeling of fresh produce – so unless retailers clearly label irradiated Australian tomatoes, consumers won’t be able to distinguish irradiated tomatoes from New Zealand tomatoes which are never irradiated.

New Zealand already accepts a number of irradiated tropical fruit from Australia that we don’t grow in New Zealand such as mango, papaya and custard apple. These fruits are required to have mandatory labelling.

Efforts to zap bacteria in food are slow to catch hold

The nuclear energy that Frank Benso uses to kill bacteria in fruit and oysters has won widespread support from public health officials and scientists, who say it could turn the tide against the plague of foodborne illness.

0408_bananafood_mainThe Food and Drug Administration has approved the use of radiation to wipe out pathogens in dozens of food products, and for decades it has been used in other developed countries without reports of human harm.

But it has barely caught on in the United States. The technology — called irradiation — zaps bacteria out of food and is highly effective, but for many consumers it conjures up frightening images of mutant life forms and phosphorescent food.

Benso, who opened Gateway America 18 months ago, also knows his new venture pits him against the nation’s growing buy-local, back-to-nature movement that shuns industrial food processing.

“Those naysayers better throw out their microwaves, because that is irradiation,” Benso said, standing in his 50,000-square-foot irradiation facility.

Dozens of scientific studies have shown that irradiated food is safe for human consumption, and that no radioactive material has leaked outside any U.S. plant, according to the U.S. Nuclear Regulatory Commission. The three forms of energy that can be used — gamma rays, electron beams and X-rays — can virtually eliminate bacteria in minutes. All this has prompted the World Health Organization, the American Medical Association, the U.S. Centers for Disease Control and Prevention, and dozens of other groups to endorse its use.

Michael T. Osterholm, director of the Center for Infectious Disease Research and Policy at the University of Minnesota, blames an “anti-science movement” for the public resistance. He is frustrated with the federal government for endorsing irradiation but then not educating the public as it has with childhood immunizations and water fluoridation.

Beam me up: renewed calls for beef irradiation in Canada

Reynold Bergen, science director of the Beef Cattle Research Council, writes that irradiation has been used to pasteurize astronauts’ food since 1966.

Irradiation is also approved as a food safety treatment in over 50 countries back here on earth. For example, France, Belgium and the Netherlands use irradiation to combat foodborne pathogens in frogs’ legs, seafood, and poultry.  The U.S. has approved irradiation of meat. Canada has approved irradiation for spices, seasonings, flour, onions and seed Irradiation-beef-Cattlemens-Association-Canada-ionizing-radiation-Ecoli-bacteria-pathogens-EDIWeeklypotatoes, but not meat or poultry. Irradiation is safe for human food use at doses more than eight times higher than those approved for meat in the U.S. Irradiation does not cause the meat to become radioactive, and has less of an effect on food nutrients than cooking does, but irradiation can have undesirable effects on flavour or colour under some conditions.

Dr. Rick Holley at the University of Manitoba recently published two papers from research funded under Canada’s Beef Science Cluster.

One paper (Meat Science 96:413-418) examined whether a low dose (one kGy) of non-radioactive, ionizing electron-beam irradiation can eliminate verotoxigenic E. coli (VTEC) and salmonella from beef trim.

VTEC, also known as Shiga toxin-producing E. coli or STEC, are E. coli that can cause illness in humans. E. coli O157:H7 is one of about 200 serotypes of VTEC. More than a third of VTEC-related illnesses in humans are also caused by non-O157 serotypes such as the “top 6” E. coli O26, O45, O103, O113, O111, O121 and O145. Salmonella is relatively uncommon in beef, but is more irradiation resistant than E. coli because salmonella is better at repairing DNA damaged by irradiation.

The second paper (Journal of Food Science 78:920-925) examined whether e-beam irradiation of beef trim affects the colour, aroma, texture, juiciness or flavour of beef patties.

Over 30 different VTEC (including E. coli O157:H7 and the “top 6” non-O157 VTECs), and six different salmonella serovars were screened for resistance to the one-kGy e-beam. Twelve of these bacteria were then pooled in four groups to test for survivors on beef. Fresh muscle pieces (outside flat, inside round, brisket, and sirloin) were separately inoculated Unknownwith either 1,000 bacteria/gram or 10 million/g of each of the four bacterial mixtures. These numbers are up to a million times higher than would normally be found in beef. The inoculated beef was exposed to a one-kGy e-beam. Surviving bacteria were recovered and counted during storage at 4 C for up to five days. Inoculated muscle pieces were also pre-treated with five per cent lactic acid before being frozen and exposed to the e-beam.

For sensory tests, the same types of fresh muscle pieces (but not inoculated with bacteria) were treated with the one-kGy e-beam. Fresh ground beef patties (10, 20 or 30 per cent fat) were separately formulated with zero, 10, 20, 50 or 100 per cent lean beef treated with the one-kGy e-beam, cooked and evaluated by a similar panel for colour, aroma, texture, juiciness and flavour.

In spite of the artificially high level of experimental contamination, treating fresh beef with the one-kGy e-beam eliminated more than 99.99 per cent of the VTEC E. coli and 99 per cent of the salmonella. The e-beam had less effect on salmonella when used on frozen beef, but this could be overcome if the beef was dipped in five per cent lactic acid before freezing.

The trained panel observed no effects of irradiation on the colour, aroma, texture, juiciness or flavour of beef patties, even when they were made entirely with beef that had been e-beam treated.

Irradiation was highly effective even in beef that was experimentally contaminated with up to a million times more bacteria than would be found in retail beef. Under normal processing conditions, a one-kGy e-beam would be expected to eliminate the hazard represented by all types of VTEC E. coli. Low-dose (one-kGy) e-beam treatment can effectively control E. coli O157:H7, non-O157 VTEC E. coli and salmonella in fresh beef trim. The e-beam did not significantly affect any sensory attributes of the beef patties, regardless of how much irradiated beef they contained. Low-dose e-beam treatment of beef trim to formulate ground beef appears to be a viable pathogen mitigation process that does not affect product quality.