Food-borne bacteria of importance to human health, must be controlled along the modern food production line. This requires an understanding of their physiology facilitating the subsequent targeting of those features that can be included as processing intervention measures. These steps are designed, based on scientific knowledge to reduce numbers or eliminate the hazard.
For this self-directed exercise, select four food-borne bacteria that you consider to be important and necessary to control.
Table of food-borne bacteria showing the associated features relevant to food safety.
Processing Options to Inactivate the Identified Bacteria
Preventing food contamination with C. perfringens involves the thorough cooking of food, especially meat and poultry. The cooked food ought to be sustained at a temperature of 60 oC (Silva 2016). The reheating of foods should be done at 74 oC for at least 15 seconds (Talukdar et al. 2017). However, if the food is to be preserved, refrigeration needs to be at temperatures of 5 oC or lower. Frozen food must attain the recommended temperature within 4 hours.
Conversely, food stored in the refrigerator should be divided into small portions that are 3 inches thick or thinner to facilitate faster cooling. Effective cooling inactivates spores and prevents them from germinating. Talukdar et al. (2017) report that C. perfringens spores are highly resistant to temperature treatment compared to vegetative cells. Therefore, higher temperatures together with other treatments may be needed to kill bacterial spores. Examples of such treatments include the concurrent application of temperature (approximately 100°C) and ultrasound treatment for half an hour or pretreatment of food with gamma radiations followed by temperature treatment.
C. jejuni is highly sensitive to heat treatment as well as other sterilisation methods such as chlorination. The deactivation of C. jejuni in food involves the thorough cooking of meat, fish and poultry. When cooking poultry, chefs need to ensure that the thickest parts cook to between 70 and 80 oC (Lahti et al. 2017). On the other hand, when preparing stuffed poultry, the stuffing should not be cooked inside the bird.
Prepared foods ought to be refrigerated within two hours. A study conducted by Garcia et al. (2018) showed that thawing meat at room temperature promotes the growth of C. jejuni. Therefore, meat and poultry are supposed to be defrosted in the refrigerator or microwave while taking care not to spill the juices that are released. In addition, recipes ought to use pasteurised milk. Proper hygiene practices are also important, for example, the thorough washing of hands, especially when handling raw meat. Food processing surfaces should be cleaned methodically with lukewarm water and detergent prior to and following their use in the preparation of raw meat.
Food safety practices in the preparation of food to avoid Salmonella poisoning include cooking eggs and meat fully until they reach internal temperatures of 71 oC (McMinn et al. 2018). Proper cooking methods need to be used to ensure that food reaches the required temperatures. For example, microwaves should not replace conventional cooking methods because the recommended internal temperatures may not be reached. Chefs ought to avoid serving foods containing raw milk or eggs. Therefore, recipes that include milk nee to use only pasteurised milk. One needs to always adhere to proper handwashing practices.
Uncooked meats should not be allowed to touch foods that will be eaten raw, for example, salads and fruits. Separate storage compartments and food preparation equipment can be used to prevent cross-contamination. Guffey et al. (2016) also recommend irradiation of potentially contaminated food with blue light at a wavelength of 464 nm and a maximum dosage of 18 J/cm2. This method leads to the destruction of 80 to 100% of contaminating Salmonella on food.
Food processing options that might be suitable for the inactivation of E. coli in food include cooking ground beef products completely at temperatures of approximately 71 oC for 15 minutes (Rauf, Silverstein & Silverstein 2016). On the other hand, already cooked foods need to be reheated to 73 oC for 15 seconds to inactivate the pathogen (Gill et al. 2016). Foods need to be refrigerated at temperatures of 5 oC or lower to prevent the growth of the bacteria during storage.
Apart from observing the described temperatures during the preparation and storage of food, it is important for food handlers to observe high standards of hygiene to avoid introducing the bacteria to cooked or raw food. Proper hand washing methods should be used when handling raw ground beef. Additionally, food surface contacts, as well as utensils, are supposed to be sanitised properly using hot, soapy water before and after they make contact with raw meat. Raw foods need to be kept and handled separately. For example, cutting boards used for meats should not be used to cut raw vegetables and fruits.
Reference List
Garcia, MB, Kinman, LA, Speshock, J & Harp, R 2018, ‘Survival of possible pathogens in ground beef during basic food-handling practices’, Meat and Muscle Biology, vol. 1, no. 2, pp. 120-120.
Gill, CO, Devos, J, Badoni, M & Yang, X, 2016, ‘Inactivation of Escherichia coli O157: H7 in beef roasts cooked in conventional or convection ovens or in a slow cooker under selected conditions’, Journal of Food Protection, vol. 79, no. 2, pp. 205-212.
Guffey, JS, Payne, WC, Motts, SD, Towery, P, Hobson, T, Harrell, G, Meurer, L & Lancaster, K 2016, ‘Inactivation of Salmonella on tainted foods: using blue light to disinfect cucumbers and processed meat products’, Food Science & Nutrition, vol. 4, no. 6, pp. 878-887.
Lahti, E, Löfdahl, M, Ågren, J, Hansson, I & Olsson Engvall, E 2017, ‘Confirmation of a campylobacteriosis outbreak associated with chicken liver pâté using PFGE and WGS’, Zoonoses and Public Health, vol. 64, no. 1, pp. 14-20.
McMinn, RP, King, AM, Milkowski, AL, Hanson, R, Glass, KA & Sindelar, JJ 2018, ‘Processed meat thermal processing food safety-generating D-values for Salmonella, Listeria monocytogenes, and Escherichia coli’, Meat and Muscle Biology, vol. 1, no. 2, pp. 168-179.
Rauf, D, Silverstein, A & Silverstein, V 2016, What you can do about food poisoning, Enslow Publishing, LLC, New York, NY.
Silva, FV 2016, ‘High pressure thermal processing for the inactivation of Clostridium perfringens spores in beef slurry’, Innovative Food Science & Emerging Technologies, vol. 33, pp. 26-31.
Talukdar, PK, Udompijitkul, P, Hossain, A & Sarker, MR 2017, ‘Inactivation strategies for Clostridium perfringens spores and vegetative cells, Applied and Environmental Microbiology, vol. 83, no. 1, pp. e02731-16.