Occurrence, heat and antibiotic resistance profile of Bacillus cereus isolated from raw cow and processed milk in Mezam Division, Cameroon

Abstract

Bacillus cereus is the aetiologic agent of two distinct forms of food poisoning: the diarrhoeal and emetic syndromes. Little data exist on the prevalence of B. cereus in raw milk and milk products sold in Cameroonian towns. This study was aimed at investigating the occurrence, heat and antibiotic resistance of B. cereus isolated from raw milk and selected milk products in Mezam division, Cameroon. Bacillus cereus was isolated by inoculating samples onto mannitol‐egg yolk‐polymyxin B agar. Isolates were characterised morphologically and biochemically. The occurrence of B. cereus in raw milk (8.22%) was less than that in milk powder (13.33%). Bacillus cereus was not isolated from fermented milk. There was no significant difference (P < 0.05) between the B. cereus load in raw milk (2.6 × 103 cfu/mL) and milk powder (3.0 × 102 cfu/mL). All the isolates showed haemolysin activity and were sensitive to tetracycline, gentamicin, chloramphenicol and nalidixic acid, but resistant to penicillin, ampicillin and trimethoprim/sulphamethoxazole. The detection of drug‐resistant, haemolysin‐positive isolates should serve as a warning for an impending health hazard following consumption of untreated milk. Heat resistance of isolates was assessed by determining the decimal reduction time; D‐value (time to inactivate 90% of the B. cereus spores); and the heat sensitivity, z (temperature increase leads to a tenfold reduction in the D‐value). The values for D100 ranged from 0.5 to 3.5 min, and z‐values ranged from 10.0 to 32.6 °C. These results could be used in the dairy industry to evaluate the importance of heat treatment on B. cereus inactivation and calculation of process efficiency.

Control ofBacillus cereusspore germination and outgrowth in cooked rice during chilling by nonorganic and organic apple, orange, and potato peel powders

“…To minimize the broader risk to consumers and to enhance microbial food safety, the described approach merits extending to brown rice and the rice products mentioned earlier, as well as to other food categories, including meat and dairy products, pasta, soups, dehydrated potatoes, and infant foods (King, Whyte, & Hudson, ; Rønning, Asp, & Granum, ; Soni et al, ). Moreover, future studies should also determine if these peels, and possibly others such as those derived from olives, pomegranates, and tomatoes, could control spore germination of both nonresistant and antibiotic‐resistant B. cereus (Friedman, ; Tatsinkou Fossi, Tatah Kihla Akoachere, Nchanji, & Wanji, ). It would also be of interest to determine if other virulent sporulating pathogenic foodborne and medical bacteria that include Clostridium botulinum , Clostridium difficile , and Clostridium perfringens would also be susceptible to the highly bioactive organic and nonorganic apple and orange peel powders that effectively controlled germination and outgrowth of B. cereus spores.…”

Lactic acid bacteria from traditionally processed corn beer and palm wine against selected food-borne pathogens isolated in south west region of Cameroon

“…However, the prolonged use of antibiotics in these regions has been indexed as the main cause of the occurrence of bacterial strains resistant to antibiotics. The emergence of antibiotic resistant strains is a major public health problem (Tatsinkou et al, 2016). The exploitation of the inhibitory activity of the lactic bacteria appeared in recent years as an alternative treatment and even prevention of some foodborne toxiinfection (Mezaini et al, 2009;Obi et al, 2015;Khalid, 2011).…”

Presence of Bacillus species in pasteurised milk and their phenotypic and genotypic antimicrobial resistance profile

“…The high sensitivity to chloramphenicol, ciprofloxacin, co‐trimoxazole, gentamicin, meropenem, streptomycin, tetracycline and vancomycin (Table 2) in this study was similar to the available literature (Tatsinkou Fossi et al . 2017; Alanber et al . 2020; Radmehr et al .…”

“…A high prevalence of resistant Bacillus species from dairy samples has been reported, including resistance to ampicillin, cephalothin, ceftriaxone, oxacillin, penicillin and trimethoprim/sulfamethoxazole (Tatsinkou Fossi et al . 2017; Radmehr et al . 2020; Zhao et al .…”