Emergence of LED based bacterial destruction technology- Opening up a new avenue for safeguarding foods

Technology for food preservation has evolved over a hundred years in the past and from the early findings that salt, sugar, acids can protect foods from deterioration by pathogenic microorganisms, modern food technology has been able to innovate newer processes with more reliability and assurance. Canning was considered the most trustworthy process and during various wars canned foods formed the backbone of the fighting soldiers. Emergence of technologies like irradiation, High pressure processing, controlled environment storage/packing, HTST etc are now available to the industry for different types of products. Ultimately the effectiveness and acceptability of a technology depend on its ability to preserve the quality of the food processed, achieving cent percent kill of microbes and the cost of using the technology under commercial conditions. Recent claims that blue LED rays can be an effective tool in the hands of technologists to preserve foods, offer a new option that may be acceptable to the industry. Here are more details of the same as reported recently.

"Blue LEDs in conjunction with cold temperature and acidic conditions can kill off foodborne pathogens making chemical-free preservation a possibility for a range of foods. Fresh-cut fruits and ready-to-eat meats are just some of the foods which are mildly acidic (pH 4.5) that could use this preservation technology to avoid the use of chemical preservatives and present the 'clean label' that consumers desire. A team of scientists from the National University of Singapore (NUS) has found that blue light emitting diodes (LEDs) have strong antibacterial effect on major foodborne pathogens and are most effective when in cold temperatures (between 4 and 15°C) and mildly acidic conditions of around pH 4.5. These findings were recently published in the Food Microbiology journal in June 2015. While LEDs are most commonly known as an energy-saving light source, they have also been known to have an antibacterial effect. Bacterial cells contain light-sensitive compounds that adsorb light in the visible region of the electromagnetic spectrum (400-430 nm), which is mainly blue LED light. Exposure to illumination from blue LED light can hence start off a process within the cells that ultimately causes the cells to die. Existing studies on the antibacterial effect of LED illumination mostly evaluated its efficacy by adding photo sensitisers to the food samples, or by using very close distance of less than 2 cm between the bacterial suspension and LED light source. These conditions would not be viable for application on food preservation. The NUS team, led by Assistant Professor Yuk Hyun-Gyun, from the Food Science and Technology Programme at the NUS Faculty of Science, is the first so far to show that factors such as temperature and pH levels, which are typically related to food products, can affect the antibacterial effect of LEDs.
In this study, the team placed three major foodborne pathogens — Listeria monocytogenes, Escherichia coli O157:H7 and Salmonella Typhimurium — under blue LED illumination and varied the pH conditions from acidic to alkaline. The team found that higher bacterial inactivation was achieved at acidic and alkaline pH conditions than when neutral. In particular, acidic conditions were more detrimental than alkaline conditions for L. monocytogenes. For E. coli O157:H7 and S. Typhimurium, alkaline conditions were most detrimental although acidic conditions were also sufficiently effective in deactivating them. A previous study in 2013 by the same team had also looked at the effect of temperature on blue LED's ability to deactivate bacterial cells and found the antibacterial effect to be most enhanced in chilling temperatures. Asst Prof Yuk said, "Taken together, our two studies point to a potential for preserving acidic foods in combination with chilling temperatures without chemical treatments. This could meet the increasing demand for natural or minimally processed foods without relying on chemicals such as acidulants and artificial preservatives to preserve food products."

Though blue light rays are used widely for a variety of applications, its utility to food preservation is some what new deserving further development to bring it to wide scale use commercially. The major constraint has been that photo sensitizers are required to activate the kill effect of the blue rays. Also the efficiency of blue rays depends largely on the distance between the food sample and the source of the light. Though cold temperature and pH conditions can enhance the kill effect, how suitable equipment can be designed for large scale commercial application needs to be addressed. If these problems are overcome, blue ray technology may find wide applications in future in the industry, retail stores and domestic refrigerators, especially to protect cut fruits and vegetables, meat cuts and other perishable foods

V.H.POTTY
http://vhpotty.blogspot.com
http://foodtechupdates.blogspot.com

Mechanical tenderization of meat-Safety apprehensions not addressed on priority

Meat products happened to be one of the most frequently contaminated foods in the US market and in spite of stiff guidelines and regulatory controls food poisoning incidences are becoming a constant source of concern to the safety authorities in that country. The industry is also mired in controversy on account of the frequent use of popular antibiotics in the feeds, contented to be for increasing the body weight of the animals during the growth stage. Obviously the antibiotics residues are bound to be in the meat derived from such animals and consequently incidence of infection can be expected to be less frequent. Still contaminated meat products make news in the US more and more frequently and there is considerable apprehension among the consumers regarding consequences of consuming infected meat products. Added to this worry is the use of newer technologies like mechanized tenderization which theoretically can increase the potential for contamination if proper precautions are not taken. Repeated attempts by consumer activists to force the meat industry to distinguish mechanically tenderized from conventionally processed products are being resisted by the processors and the safety agency seems to be willingly playing into the hands of the meat industry lobby by delaying the mandatory labeling requirement under one pretext or the other. Here is a take on this issue.

"For more than a decade, consumer groups and the U.S. federal government have been discussing the food safety concerns surrounding mechanically tenderized beef — steaks or other whole cuts that have been mechanically punctured with needles or knives to make them more tender for consumers. In the U.S., roughly one-quarter of whole beef cuts are mechanically tenderized. Mechanical tenderization of beef poses health risks because it transfers potential pathogens from the surface of the meat down into the center If the cuts are cooked rare or not thoroughly enough, the pathogens in the center may go on to sicken the consumer. A number of foodborne illness outbreaks have been connected to mechanically tenderized beef in recent years, including the 2012 outbreak of E. coli O157:H7 in Canada from XL Foods, which resulted in the largest beef recall in Canadian history. According to USA Today, at least five outbreaks in the U.S. have recently been attributed to mechanically tenderized beef, resulting in 174 confirmed illnesses and four deaths. The problem with tenderized beef is that without a label, it's impossible to tell whether or not a cut of meat has been tenderized, said Patricia Buck, executive director of the Center for Foodborne Illness Research & Prevention (CFI). Anyone who might want to take extra precautions to avoid E. coli or other pathogens in their steak has no way to identify the additional risk without a label. That's especially concerning for children, the elderly, or any other consumers with weaker immune systems, Buck said. In a federal register notice from June 2013, the USDA's Food Safety and Inspection Service (FSIS) estimated that E. coli illnesses from mechanically tenderized beef ranged between 587 and 4,657 each year. Labeling that beef could prevent an estimated 133 to 1,497 of those illnesses, the agency said, which would translate into roughly $1.5 million in economic benefits from avoided illnesses each year. "When we're trying to reduce the prevalence of foodborne illness, labeling mechanically tenderized beef is one quick fix that has an actual impact," Buck said.'

It is not understandable as to why the industry is so fiercely opposing such consumer friendly labeling system forgetting that the very foundation of its business is built upon confidence and trust between them. Same trend is seen in the case of GM foods also where repeated attempts by the consumer organizations to label them are being rebuffed by the industry through means which cannot be considered fair. industry may claim that their products are perfectly safe but it is the inalienable right of the consumer to know what he is buying and therefore if he wants to know if the meat is mechanically tenderized he must know about it to take a decision to buy or not. If the law says irradiated foods, considered absolutely safe, need labeling why not mechanically tenderized meat products also? Further prevarication by the safety agencies cannot be condoned at all. 

V.H.POTTY

http://vhpotty.blogspot.com/
http://foodtechupdates.blogspot.com